They claim a 3-4 year payback on these electric water heater heat pump systems. I am thinking of going this route instead of solar hot water because it’s a much longer payback time and a much higher installation cost with solar hot water.

Rheem Hybrid Heater

What do you guys think?

The payback is def better than Solar Thermal, and a properly installed HPWH will use less kWh than a badly installed solar system.

Third party tests liked the Rheem less than the GE, and liked the AOSmith best of all. On the basis of COP.

Their report is too big to post....Google "HPWH_Lab_Evaluation_Final_Report_20111109.pdf"

My only problem with HPWHs is that they basically use the same systems as a fridge and they don't last as long as they used to. They are still new (at least GE is) on the market, just a few years so I wonder what the lifespan really is, considering how long a fridge will last these days.

That said, what is your definition of green? A solar water heater is a green product and a HPWH is, hopefully, an energy efficient product( which could be green if powered by PV). Different thing from my perspective. Payback muddies the waters.

I would also look at the Steibel Eltron if it is available in your area.

I see that the GE ones are $1000 now. They are taking heat from the interior, so the numbers get better in hot climates (with AC) and worse in cold climates. Now if they would just combine it with the refrigerator.....

With a nod to jonr's idea about combining the water heater and the refrigerator, I did think about putting one in a walk-in cooler, but unless you have the proper airflows, you can end up taking heat from the interior just the same. I had a hard time figuring out how to use one here in Washington state, but in a hot climate they would be pretty interesting.

Posted By jonr on 20 Aug 2012 09:19 AM
I see that the GE ones are $1000 now. They are taking heat from the interior, so the numbers get better in hot climates (with AC) and worse in cold climates. Now if they would just combine it with the refrigerator.....

The AirGenerate AirTap has ducted outdoor air as one possible installation configuration, which would work OK in temperate-cool climates. It's ability to make hot water with the heat pump falls off a cliff below ~20F source-air, so it's usefulness in climates cooler US climate zones 1-4 is pretty limited.

[edited to add]

In a more careful read of the installation manual, the ducted air is exhaust-only (and 400cfm!), which means it sucking in that much outdoor air somewhere else in the house. That's only more efficient than some other heat pump unit if the exhaust air is cooler on average than the outdoor air it's sucking in, which might work for climate zone 4, but maybe only the warmer edge.

Just have a thought about these types of water heaters in mixed northern climates.

There's probably at least 6 months of the year where running one of these heat pump water heaters have beneficial cooling/dehumidifying aspects. The GE model and I presume all of the others have the ability to switch entirely to the electric resistance heat mode. Why not just switch to the all electric mode during the months where the cooling/dehumidifying benefits aren't there? I bet that the unit's operating cost is still better than heating water with propane.

Now, if you have natural gas service, it's probably significantly cheaper just to go that route.

Sure in the winter, switch it to electric mode if electricity is lower cost than propane. But if that's the case, you should heat your whole house with electricity.

Here again the USA lags FAR behind the rest of the world. There are literally hundreds of "split" DHW heaters made in China these use an outdoor section that usually looks like that of a "minisplit" and an indoor section with refrigerant lines between. Typically the indoor section is basically the DHW tank. Some advertise operation down to -20c, (-4f) before they drop to a COP of 1 and revert to resistance heating. Above 40 f the COP typically exceeds 3. What that means is they use less electricity than an ordinary electric DHW heater whenever it's warmer than -4f and over a year less than half as much in any US climate.

I thought the mini-split type water heater was a Japanese invention (but yes, they're not new.)  The Japanese also have combo refrigerator/HW-heaters sized about right for typical Japanese-kitchen hot water use.  Both make more total net efficiency sense than the tank-top versions in cooler US climate zones.

I keep getting hints that the mini-split water heaters will be coming to our shores "soon", but keep hearing the same rumors about CO2-refrigerant air source heat pumps too- I'll believe it when I see it.  As I understand it most of the mini-split type water heaters are CO2 refrigerant (to be able to deliver the higher output temps of DHW efficiently) not R410A like most mini-splits sold in the US. 

The Nippondenso "Eco Cute" water heater is a CO2 type, and has more than a decade of real-world use behind it now.   I'm not sure of the relationship between Sanyo & Nippondenso (aka Denso), but they're selling what appears to be same line of water heaters under the same "Eco Cute" name. It was apparently a consortium that came up with the first versions.  (I'm sure there are many imitators in Asia using a variety of refrigerant & compressor types.)  It could be that whatever regulatory hurdles slowing the import to the US of hydronic output CO2 heat pumps for the space heating market are the same for the Eco Cute.   Both  Sanyo and Denso space-heating hydronic heat pumps are well suited to many homes with radiant heat in US zones 5 & 6, but there is no telling when they will arrive.

The Daikin Altherma air-to-hydronic heat pump (R410A) has DHW heating capabilities though, and is available in the US, but it's bigger deal than the DHW-only heat pumps.

Before you by an air-source heat pump water heater, call a few hundred plumbers and see if any will come out to service the one you are interested in.

It never pays to get too far ahead of the curve, particularly when the return on investment is 10 -20 dollars a month.

I'd be more interested in (and more likely to become an early adopter) if the heat-pump was a CO2 refrigerant unit with a 9kw+ output rating (big enough to more than handle my average mid-winter heat load, and natural gas was $2/therm, eh? ;-)

The tank-top units might make financial sense in 25cent/kwh cooling dominated places like HI (where the ROI would be over $50/month) but approximately never in 7cent/kwh parts of the heating dominated upper midwest.

For some hard-to-fathom reason they're heavily subsidized in MA- enough to cover the cost of the unit (the costs are essentially just the installation after rebate, for the smaller GEs at box store pricing.) The only rationale I can think of for the subsidy here is that by combining HW heating and the air conditioning benefit reduces peak-power loads/costs to the utility during the cooling season enough to for them to kick in something, but for the fixed-rate residential customer there's very little advantage if any. The wholesale price of peak-power to the utilities during the air conditioning peaks are several times the fixed-rate residential rate that they can charge.

The way the utilities are regulated in MA they make more money by reducing load than by building new generating capacity, so there's probably some analysis to show that 500,000 GeoSprings = 1 gas fired peaker that they don't have to build, or something like that. Beats me.

Our rural coop (Minneapolis Metro) offers a "interruptable" power plan, and shuts off power to A.C., DHW and space heating during peak hours. All the same game. Gov't. getting in the way of building new crucial power plants and regular folks getting by. In Japan, where all power is imported, extraordinary machinery makes sense. It might even help N. Americans when we run out of buck-a-therm natural gas in another couple of generations.

Posted By BadgerBoilerMN on 23 Aug 2012 05:40 PM
Before you by an air-source heat pump water heater, call a few hundred plumbers and see if any will come out to service the one you are interested in.

It never pays to get too far ahead of the curve, particularly when the return on investment is 10 -20 dollars a month.

Supposedly it comes with a 10 year warranty and Rheem assists in finding a qualified company.

Posted By Liebler on 23 Aug 2012 02:53 PM
Here again the USA lags FAR behind the rest of the world. There are literally hundreds of "split" DHW heaters made in China these use an outdoor section that usually looks like that of a "minisplit" and an indoor section with refrigerant lines between. Typically the indoor section is basically the DHW tank. Some advertise operation down to -20c, (-4f) before they drop to a COP of 1 and revert to resistance heating. Above 40 f the COP typically exceeds 3. What that means is they use less electricity than an ordinary electric DHW heater whenever it's warmer than -4f and over a year less than half as much in any US climate.

You can say that again. The main thought and practice of builders here is that homes must "breathe" and they build them leaky because it helps the home to breathe.

Have any of you cold climate guys considered the gas absorption heat pump? Natural Gas COPs are 1.4 to 1.7, some electricity is required.

Posted By BadgerBoilerMN on 23 Aug 2012 06:24 PM
Our rural coop (Minneapolis Metro) offers a "interruptable" power plan, and shuts off power to A.C., DHW and space heating during peak hours. All the same game. Gov't. getting in the way of building new crucial power plants and regular folks getting by. In Japan, where all power is imported, extraordinary machinery makes sense. It might even help N. Americans when we run out of buck-a-therm natural gas in another couple of generations.

Now that we're straying off topic...

The interuptible power is often referred to in the power industry as "demand response" capacity, putting some control of the grid-load in the hands of the grid operator to avoid the steep capitalization & operating costs of peak power generation.  The capital costs of peakers are very expensive, far in excess of the fuel costs since their capacity factor (the average output over a year divided by the max output capability) is typically in very low double-digits- under 20% and in some places it's in single-digits. (Compare this to the "unreliable" power of large scale wind, that comes in with capacity factors of about 30%.)  Building and maintaining a powerplant that's use at 10-20% capacity is expensive no matter what the fuel costs are, and they HAVE to charge a premium for their power to have a business. Buying the same grid capacity in "nega-watts" with demand-response control is much cheaper to the grid operator and ultimately the ratepayer, while grid reliability goes up:  Brown-outs (or worse) become less likely.

As grids get smarter more demand response can be built in, which is just one method of "grid hardening" variable output renewable sources such as wind & solar.  It's unlikely that signing up for demand-response on bigger loads would be required of residential customers, but by giving customers who sign up for the variable rates with some demand-response on heavy loads like central air conditioners, electric clothes dryers, and water-heater, then giving them acces t real-time grid pricing information via smart meters it residential customers can (voluntarily or automatically, or a combination thereof) make a huge dent in their power bills.  It's not for everyone, but where these schemes have been tried out almost nobody who signs up for demand response opts out later.

Demand response is under intense development in Japan- critically necessary due to both their bizarre split-grid and the shut down of a large fraction of their baseload capacity after the tsunami/Fukushima disaster.  Half the country if 50Hz 220V, Euro-style, half is 60Hz, 110V, N-American style, with only limited capacity to share power between the two.  It's simply not possible to build new generation capacity (of any type) quickly, but implementing demand response to put upper bounds on the grid load is both (relatively) cheap and quick.  But it's far more than a band-aid- it's putting Japan in the forefront of the technology to implement & manage smart-grids.  Japan WILL build more generating capacity going forward, but a smarter grid allows them to minimize capitalization costs by maximizing capacity factors on all of their grid sources.

Taking it even further off-topic...

As much as the detractors of wind-power make an issue out of it's variable output & comparatively low capacity factor, the levelized cost of energy for wind at at the current ~30% capacity factor (including all capitalization & maintenance costs) isn't dramatically higher than cheap-gas burned in state of the art combined-cycle gas plants, and is CHEAPER than power burned in simpler gas-thermal plants (at any capacity factor, not just low CF peakers).  That cost has also been coming down at a rapid rate as wind technology matures and manufacturing rates increase. Even without subsidy there is an economic argument for grid operators to continue wind development even in the face of cheap gas.  With wind the vast majority of the cost is in the capitalization, and once the it is built the marginal cost per kwh is near zero, and the levelized cost per kwh is a fixed, very stable number that can be counted on.  In parts of the US where wind has been more heavily developed (notably TX & IA) the low marginal cost/kwh of wind has had the effect of depressing the price of power to both the grid operator and the ratepayer, since in the day-ahead market (how most wholesale power is bought & sold in the US) wind, like (hydro & nukes) is a $0 bidder- they accept whatever the rest of the market will charge, and when the wind blow hard it displaces powerplants with fuel costs, and the excess wind is purchased at whatever the next-cheapest generators bid was, even when it's below the overall levelized cost for wind. This puts the operators of marginal thermal plants with real fuel costs that cannot be discounted at a disadvantage, eating into THEIR capacity factor.  But it puts a damper on the overall average cost & prices from which ratepayer rates are derived.

Even with cheap gas there is cost-volatility related to the non-stable price of the fuel, and while they are at historical lows now, there's no room for them to fall further- at ~$2/MMBTU gas operaters start capping off shale-gas wells that don't have sufficient liquids that can be sold a higher price- they're too unprofitable to even pump.   At $4/MMBTU gas the levelized cost off wind power is cheaper even at 2010 wind costs, and the cost of large scale wind has come down since then.  It is in grid operators' longer term interest to continue to build up a wind portfolio even in the face of cheap gas as a hedge against fuel price volatility and against potential future carbon taxes.  With the development of smarter grids and greater demand response capacity cheap-wind may come to dominate some local markets LONG before the cheap gas runs out.  Given that on a levelized cost basis it's below grid-parity in some markets RIGHT NOW now, wind has a future.  Whether wind continues to get the benefit of a Federal subsidy only affects the rate of implementation, but not the eventual grid-share.  A rapid shut down of Federal support (as may very well happen) will be disruptive to the industry and may scale back or halt some recently developed or planned manufacturing capacity, but it's not necessarily a death knell, as some wind advocates have suggested.

> gas absorption heat pump

Are there readily available systems out there for residential use? They aren't very efficient for cooling, but for heating, 1.4 is better than .95. http://www.ornl.gov/adm/partnerships/factsheets/10-G01078_ID2389.pdf

No offense, but the heat stealing on these units is a widely misunderstood topic. A number of frankly incorrect screeds on the intertubes are dedicated to the topic.  Folks think they are paying twice for a given BTU, once with a furnace to put the BTU in the space, and then a second time to pump it, so it has to be more expensive than just paying once (like a conventional tank).

Looking more carefully, if the unit runs at a given COP, then it only pumps (COP-1)/COP, about 50% from the space, and the remainder (also about 50%) comes from the compressor work running the pump (that, like most work, ends up as heat BTUs).  So, by this math, a HPWH still saves you money, per DHW BTU, relative to a conventional tank in a cold climate during winter, provided your space heat BTUs are cheaper than electric resistance BTUs (which is almost always the case).  It just saves you less than it does in the summer.

In summary, half the heat comes from your grid, at a cost/BTU the same as a conventional tank.  The remaining BTUs from your space have to be made up, but only at the cost/BTU of your central furnace (and then only during the heating season).

In summary, half the heat comes from your grid, at a cost/BTU the same as a conventional tank.

You are adding to the confusion. For example, the above is not true when comparing a HPWH to a conventional nat gas water heater (a common case).

Back when, I kicked around the idea of using a HP hot water heater to temper passive solar in a lower-mass, well insulated house. You mount it in a chimney chase or similar ducted location and put it on a thermostat so it runs at temps above 75. A heat dump loop connecting a water/glycol heat exchanger in the tank with an air/glycol HX outside would keep it running. You'd oversize HP and tank. You could add 55-gal drum-type tanks in series until you got storage right. The same dump loop could provide heat overnight with a second glycol/air HX in your chimney chase. In the summer the heat dump would allow the HP to operate as on-demand air conditioning.

On the minus side, it's hard to find residential stand-alone HPs of decent size. E-Tech still had these 1-ton units a couple years back. http://www.etechbyaosmith.com/res_waterheating.html AO Smith apparently wanted E-Tech for commercial stand alones, so larger units should be available.

Posted By jonr on 25 Aug 2012 09:01 AM

In summary, half the heat comes from your grid, at a cost/BTU the same as a conventional tank.

You are adding to the confusion. For example, the above is not true when comparing a HPWH to a conventional nat gas water heater (a common case).

Not trying to confuse.  Ok, you can read my note as 'conventional **electric** tank'.  The point is that compared to a conventional electric tank, a HPWH will be cheaper to run in all 12 months, in a heating climate or a cooling climate (unless your space heating BTUs cost more than electric resistance BTUs, in which case you have other problems.).  When I was researching my purchase of one, I read a ton of stuff that suggested otherwise....not unlike some comments in this thread.

I'm pretty sure we're on the same page- it will NOT be cheaper to run in the winter in a heating dominated climate in a resistance-electric heated home. But it'll be cheaper to run when there's a cooling load.

But whether it has a financial rationale within the lifecycle of the equipment in locations with 8-9 months of heating-load and only very modest cooling loads and short cooling seasons is a dubious proposition, requiring more in-situ data from carefully & separately metered the cooling, heating, and HW heating loads than has been published to date. If the heating season is 8 months out of the year it's going to be a hard financial argument to make with resistance-electric as the space heating source.

Adding a gas HW heater and gas heating to the mix confuses the situation, but rare is the cool-climate market where the HPWH would be cheaper to run than a gas HW heater in a house with decent-efficiency natural gas heating + central AC. In climates/markets where the annual AC costs equal or exceed the gas heating costs it might be close, but the better first-hour gallons of a gas-fired tank might still tip the balance from a "What should I buy, a gas WH or a HPWH?" perspective.

In some markets resistance electric BTUs are now cheaper than propane or oil BTUs at recent fossil-fuel prices (which is indeed a problem!) But in those situations you's get more bang per buck plowing the HPWH + electric baseboard money into ductless air source heat pumps to substantially offset propane/oil use.

Without a flame, it should be possible to make these heaters with plastic (eg, PEX or PERT) lined tanks. If the heat pump is also well made, then these could last as long as tankless heaters.

Posted By Dana1 on 27 Aug 2012 03:51 PM
In some markets resistance electric BTUs are now cheaper than propane or oil BTUs at recent fossil-fuel prices (which is indeed a problem!) But in those situations you's get more bang per buck plowing the HPWH + electric baseboard money into ductless air source heat pumps to substantially offset propane/oil use.

How about when the climate is mixed, with both cooling and heating loads. So for the Chino Valley, AZ area, do you think a Hybrid Tank like this is worth it in the long run?

Ok, Dana.

We def agree that a house with NG should burn gas both for space heat, and then either a standalone or indirect fired gas DHW tank would be the way to go. That is indeed a very common situation in the US.

However, we often find places that don't have NG, and it seems that an emerging theme is that well-designed modern ASHPs or mini-splits are a pretty ideal solution for many of those homes. Specifically, in many places they look better economically than geos.

So, I am thinking about that case...if you are using a HP for heating (ASHP or geo) does it make economic sense to buy a HPWH?? Even if you live in a heating dominated climate?? Let's go.

Hypothetically, say I get an SCOP = 2.5 on my space heating, and run a HPWH with a nominal EF=2.2 in my conditioned space. The latter includes tank losses, so its average COP (esp running in a warm conditioned space) is probably also ~2.5.

During cooling season, my elec costs 1/2.5 or 40% of an electric tank (my other goto option without NG). That is, my DHW BTUs cost 0.40 of the other option. Whether I get useful cooling or not is hard to say....I probably don't circulate the air, and their big fans limits temperature drop and dehumidifcation. And my central system has a higher COP in cooling (>4).

Now, during heating season, the unit is making 40% of its BTUs from grid power and stealing 60% from the space heat. The stolen BTUs are made by my ASHP at COP=2.5 (averaged over the season). So, a DHW BTU costs me:

0.40*1 + 0.60*0.4 = 0.64 relative to a electric tank BTU.

So, in a summer month, the HPWH costs 60% less than an electric tank.
in a winter month, the HPWH costs 1-0.64=36% less.

If we heat for 6 mos/year, then our seasonal average savings are still 1 - (0.52) = 48% cheaper than an electric tank, vs 60% cheaper than in a place with no heating (Key West?). Simple payback is only 25% longer than in a no-heating climate.

We could argue that the cooling effect is economically relevant, but on the other side, stealing heat from an unfinished basement might not boost the space heating demand on a 1:1 basis, etc.

My argument is that in a HP heated home in a climate that gets real winter, the HPWH still saves ~50% on a seasonal-average basis, NOT counting the cooling benefit at all, but scoring the heat stealing at 100%. For a family of 4 with typical electric costs, an electric tank might cost $500/yr, and the HPWH would save $250/yr. IN a cooling dominated climate they would save $300/yr under the same (conservative) assumptions. If the incremental cost of the HPWH is ~$1000, this is a simple payback of 3-4 years on units that have a (limited) 10 yr warranty (or faster payback if you get rebates or score the cooling benefit).

IOW, I see the logic of the rebate program in MA. Their customers will reduce their demand significantly, esp during the summer peaks (reheating the tanks midday after morning showers).  By my reckoning, those oil-burners in MA are still getting their BTUs for ~60% of the cost of electric resistance heat....and the HPWH will still save those customers money in January (just about 25% relative to an electric tank).

In those parts of the US where readers might see HPs as an optimal space heating solution, HPWHs are an excellent, money saving and energy efficient addition to those homes.  Suggestions that heat stealing destroys the economics or energy savings in most US climates are not correct.

I agree with that. Personally, the choice between a HPWH and a tankless nat gas water heater would come down to issues other than operational cost. As the stickers say, it's close. I would not choose propane or electric.

Nobody has made the argument that houses heated & cooled with heat pumps wouldn't see a net benefit with a HPWH, quite the contrary (though for GSHP with desuperheater HW capacity the numbers would work differently.)

The net benefit to MA customers during the summer still don't add up to the retail price of the unit over it's expected lifecycle, which is why it NEEDS to be subsidised. The primary financial benefit is to the utility and to the entire rate-payer base benefitting from the lowered peak power, not to the owner of the HPWH. What's surprising to me isn't that it's subsidized, but the AMOUNT to which it is subisdized (which is nearly the full purchase price of the unit in some areas, making the installed cost cheaper than a standard tank), and a larger cash rebate than for installing a high-efficiency mini-split heat pump.

The reckoning on oil-boiler heating hot water vs. a standard electric tank needs adjustments to reflect typical efficiencies & heating oil/electric rate prices. The HW heating efficiency of an oil boiler is pretty abyssmal when there is no space heating load, unless the boiler is outfitted with an indirect tank (rather than an embedded tankless coil) and heat-purging boiler controls (recommended), and is a "cold start" type that can be regularly fired up cold without damage to it's heat exchangers.

A "typical" system in MA runs at between 35-40% efficiency in HW-only mode, even with an indirect. See Table 2:

http://www.nora-oilheat.org/site20/uploads/FullReportBrookhavenEfficiencyTest.pdf

During the heating season at the typical 3x oversizing it's more like 70-75% (see table 3 in that document.) If you assumed an annualized HW heating efficiency average of only 60% (which would be on the high side), at $4/gallon you're looking at ~$48/MMBTU delivered to the water.

If you're looking at the cost of the space heat extracted by a HPWH use 75% rather than 60%, that's still $38/MMBTU- in, but you still have to account for the tank's standby loss. At typical insulation levels for a 0.90 EF tank or HPWH that would make it ($38/0.9=) $43/MMBTU net.

One MMBTU=293kwh, but in straight-ahead 0.90 EF electric tank it takes (293/.9=) 325kwh. At 15 cent big-utility rates from say (about the combined residential power + delivery cost through National Grid) that's about $49/MMBTU, for the electric portion of the heat going into the water.

So yes, at $4 oil the heat extracted from the heating system from an HPWH comes at a slight discount, at $4.50 (like many I know were paying this past season), not so much.

Predicting oil pricing over the lifecycle of a hot water heater is something of a fool's errand, but the 20 year or decade-trend hasn't been encouraging, more than quadrupling since the mid-'90s low:

http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=W_EPD2F_PRS_SMA_DPG&f=W

If you're on one of the local municipal-systems with ~12 cent electricity (rather than NStar or Nat'l Grid) you're better off NOT stealing the heat from an oil-fired heating system- it would be cheaper to heat that water with resistance electricity in winter. With an HPWH you'd get maybe a 50% discount for 3-4 months, but it would cost more during the other 8 months.

If you rely on AFUE efficiency numbers for making the per-BTU cost analyis for oil it would be a mistake. Unless the boiler is a latest-technology smallest-in-class versions, the Brookhaven Nat'l Labs test data indicate true efficiency numbers well below any AFUE-test, and that's for boilers tuned up in a test lab, not the typical residential system that hasn't seen a burner-tech since it was installed (or since the last time it backfired or wouldn't fire up.) Even the smallest oil boilers out there have output 1.5x or more output than the design condition heat loads of the houses they are heating (which would be small enough to hit their AFUE numbers- AFUE testing assumes 1.6x) but energy-audit surveys in central MA indicate 3x oversizing is more typical, and that's consistent with my (albeit limited) direct experience.

The picture for $/MMBTU for propane (even at 95% condensing efficiency in a right-sized mod-con) isn't as rosy as oil, at recent prices.

I've said my peace about the merits of the these units in a HP-heated house w/o NG. I'm glad we all agree.

On the oil thing, I was reckoning from $3.50/gal (averaged over the last few years), 18 kWh elec, 80% space heating eff and not counting the tank losses from the boiler as losses (during the heating season).

Until I had it torn out, I had a 1990s vintage 1.2 gph oil boiler, and it was burning through ~0.9-1.0 gallon/day during the summer just to fire a tankless coil, at least 70% of which was standby losses or other inefficiencies. Thus, during a 150 day summer season, I could easily burn through 140 gallons, and make a bunch of heat to pump out with my AC. At $4/gal, that $560 for oil plus another ~$100 for the additional AC, for a summer DHW cost of $660 ! Installing a conventional electric tank (for summer use only) would make my DHW for ~$200, saving me $460/yr. OF course, shutting down the boiler for the summer is a bit dicey, but not as rough as trying to run it cold start on a recurring basis. (And a lot of folks shut down their boilers for extended periods). A HPWH running during the summer should have a COP ~2.5, so it could run all summer for $80, and maybe save a little AC on top of that, so I would save say $540-560 per year just running it in the summer relative to oil.

So, in the age of $4 oil, it makes sense to have some sort of summer backup and to shut down the boiler. An electric tank has a pretty nice ROI ($460/yr), and a HPWH will save an additional $1200-1500 over its 10 year warrantied life (and might last longer only running in the summer), relative to straight electric. This number doesn't seem too bad relative to the incremental cost relative to a 10 yr conventional tank.

And if the home owner elects to insall some minisplits to heat the house during the shoulder seasons (in a future period of even more expensive oil), then I can save even more with my HPWH by running it more months.

In the age of $4 oil all SORTS of things become economic if it cuts down on oil use! (And tankless coils just plain SUCK, both on flow/output and efficiency.)

A 1.2gph oil burner is about 165KBTU/hr-in/140KBTU/hr-out. Most pre-1980 mid-sized homes in MA that have had ANY sort of air-sealing or insulation upgrades since they were built still come in at under 50KBTU/hr, and often under 40KBTU/hr. With that type of oversizing, even if the AFUE or DOE efficiency of a freshly tuned burner might be in the mid-80s, the as-used AFUE at the fractional load is in the low to mid 70s, not more.

Check out the regression curves in the appendices of that Brookhaven Labs document- without heat purge and cold-start it's real part-load CLIFF. With 40K of space heating load at design condition and 140K of burner output it's never operating at more than the 30% point, and averaging near the 10% point on the curve! With an indirect HW heater and a heat-purging economizer (eg. Intellicon 3250 HW+) you can move the knee of the efficiency curve a bit higher and to the left, but it won't move too far unless the boiler is cold-start tolerant. http://www.nora-oilheat.org/site20/uploads/FullReportBrookhavenEfficiencyTest.pdf

In a house in MA with a 40K design condition heat load a 2.5-ton mini-split/multi-split is capable of reducing oil use by about 70% or more. Even though the oil-burner maybe necessary to support the design-condition load, the mean January load is only ~65% of that load, and the rest of the time it's lower still. At $4 oil and 15 cent electricity and an annual COP of about 2.7 (some do a bit better, some will do a bit worse), simple payback on the ~$6-7K upfront cost of the ductless is usually under 5 years.

Subsidies for HPWH are usually only extended to those already heating hot water with electricity, even though the financial argument even just for summertime-use is compelling for those heating water with embedded coils in oversized oil boilers. (To the grid as a whole it's still an additional load, albeit a lower load than a standard electric tank.) But applying the money toward a ductless & air sealing is still going to be a better bang/buck in most (but not all) of those houses.

The Brookhaven numbers were interesting....there is so much effort put into rejiggering controls and indirect tanks for these old-tech oil hydronic systems, and frankly, I think its all lipstick on a pig. The basic tech of a segmented, cast-iron, non-condensing oil-fired boiler....blech. Grew up with one + tankless, owned one myself (w/tankless) recently for several years.

I bought a v poorly airsealed 2300 sq ft house near Philly in 2005, with oil hydronic/tankless, and burned ~1400 gallons/yr to be uncomfortable in the winter, and to take showers that 'never runs out of hot water', but which feature wildly swinging temps and you better pray no one runs a faucet (let alone a second shower) at the same time.

After a lot of airsealing, I now have the typical January demand down to ~24 kBTU/h, maybe 40k max, and space heat with a 4 ton conventional split system HP. DHW from a AO Smith HPWH in an attached, semi-conditioned garage. Heating and DHW are currently ~9000 kWh/yr, with further room for some improvement.

And the oil boiler has gone to the scrap yard.

We couldn't agree more- even the latest condensing lowest-mass triple pass oil boilers aren't worth owning if you live in a climate where you can take advantage of heat pump technology (which includes vast majority of the lower 48 of the US now that mini-splits can run at -25C/-13F.) There's no prospect for the decade-average price of heating oil to fall much going forward (barring a worldwide economic depression that would make the 1930s look like a picnic), and there will continue to be jarring price volatilty no matter how fast the poke holes and pump.

The worldwide oil production rates will not keep up with the increased demand from developing-country transportation fuel needs, which will continue to drive the price, even as developed countries cut back. A sustained price of $100/bbl has not increased pumping by more than a few percent over the past 4 years. It went from ~84mbbl/day in 2008 to maybe 88bbl/day now mostly from increased Saudi production, as much as people like to cheer about North Dakota & Brazil coming on line.

I fully expect to see $3 heating oil again, (if only briefly) but it would take $2 oil (or cheaper) to be competitive with heat pumps in all US markets except diesel-fired generation on isolated island-grids. The scrap yard is exactly where most of those boilers belong.

Our current oil policies are like a guy in the desert with only one bottle of water - drink it fast, it will be gone soon. The result will be a hastened, abrupt and traumatic withdrawal.

... or a major bloody fight over the last 3 swigs.

Agreed - the fighting has already started.

I've looked around quite a bit but can't seem to find any split HPWH, other than the Daikin Altherma solutions. I do not want to install the WH outside, so a split unit make sense but all that I can find are self contained.

And all seem to be for water only, not space heating. I'd like to see if there are less expensive alternatives than the Daikin solutions, although I may just acquiesce and budget for the Daikin.

Daikin has several split water heaters for the Asian market (including the EcoCute consortium in Japan, using CO2-refrigerant in split hot water heaters.) There's some discussion of releasing an R410A refrigerant split system in Australia this year, but if there is plans for the US market it's in stealth mode.

Since the topic came up again- Does anyone make a reasonable, reliable heat pump water heater? I almost bought a GE unit which was half price at Home Depot ($650) until I did some research on the reliability. It is dismal on all of the lower priced units i could find. People wound up having the unit repaired or replaced repeatedly until giving up and going back to resistance heating. My ICF basement is ideal, ranging from, 55 to 75 degrees year-round. I'll probably go old-school for the time being, as I don't want the aggravation of a failing WH.

Not speaking from personal experience, but A.O. Smith apparently makes a good one. Perhaps others can post their personal experiences or anecdotes on the AO Smith units? The GE units have a massive amount of bad reviews out there (Amazon alone)

I wonder when the Fujitsu Waterstage air to water heat pumps will be available in the US. I suppose if you really want one, you just order from the UK. Or a Panasonic Aquarea T-CAP.

Posted By jonr on 17 May 2013 11:20 AM
I wonder when the Fujitsu Waterstage air to water heat pumps will be available in the US. I suppose if you really want one, you just order from the UK.

I'd be really wary about trying to hook up a high-power device designed for 230VAC/50Hz into a US power grid without prior sign off from the manufacturer.

I'm not surprised that the other Japanese mini-split builders are getting into the European hydronic-output ASHP market though.

230 VAC nominal is no issue (voltages in the UK can exceed 250V). 60Hz vs 50Hz is unlikely to be a problem given that the compressor is driven by an inverter; but I agree, check before buying.

Check out the Stiebel Eltron model. It is made in Germany and I suspect it is better than the GE.

Posted By jonr on 17 May 2013 10:14 PM
230 VAC nominal is no issue (voltages in the UK can exceed 250V). 60Hz vs 50Hz is unlikely to be a problem given that the compressor is driven by an inverter; but I agree, check before buying.

Given the bizzare standards for frequencies and voltages on the Japanese grid I'd be surprised if they didn't design it work over a wide range, but having been bitten more than once on power supplies with differing European power standards, getting manufacturer sign off on it is still important.

I have one of these in my home, and after two years, no problems. We use the "Energy Saver" mode, with a high temperature setting.

Posted By JimGagnepain on 24 Jun 2013 10:22 AM
I have one of these in my home, and after two years, no problems. We use the "Energy Saver" mode, with a high temperature setting.

You have a Stiebel Eltron?  Heat pump hybrid? (or conventional tankless? they offer many products)


The only issue I have with an all in one heatpump DWH is, I do not want to install my water tank outside, and it's not a good idea to install an "all in one heat pump DWH" inside a conditioned space, where it will cool the interior temp (starts working against itself).  And there are limitations on how far you can duct (length) the cool air by-product outside

It looks like the original poster's link is no longer valid. Here is the latest Rheem Hybrid hot water tank, which is probably close to mine:

http://www.rheem.com/product/water-heating-heat-pump-hybrid-heat-pump

Mine is a model number Rheem JPYA A050. I no longer see it on their site. Probably replaced with the above unit. It is installed inside. Mine is in a "hot" area of the house, in front of a passive solar window, where it often gets in the 90 deg F range (during the cold months).

There is an idea - use a timer to turn the water heater off during non solar hours and only let it run when the room may have an excess of solar heat gain.

Posted By jonr on 24 Jun 2013 11:19 AM
There is an idea - use a timer to turn the water heater off during non solar hours and only let it run when the room may have an excess of solar heat gain.

I could do this, but it may be overkill.  This area of our house is open to the rest of the house, so although warmer during the day, the air and temperature gradient circulates quickly.

Stirring this pot again.

I've decided to specify a hybrid heat pump DWH. Well, it wasn't my first choice but it is the most cost effective solutiong that well let me get my Title 24 compliance sheet, so I can obtain my building permit. I can always eventually look at more efficient alternatives (split unit, passive solar water heater, etc) later on down the road.

I plan on putting the Water Heater out in the garage so the heat pump will not affect conditioned air. It's not a bad plan, as my first floor mechanical room is less than 15' away from the area in the garage where the HP/DWH will be located in the garage. The garage will eventually be insulated.

My Title 24 consultant suggested the GE GeoSpring, and I told her to put that into my plan, and if I don't end up using that one, I'll use one with similar or better specs. As long as I the specs are comparable or better on the one I eventually install, I'm in compliance.

After reading all the horrible reviews on the GE, one would have to have balls of steel to go forward and install it.

The Rheem doesn't have the sample size of reviews, some are good, others are not so good. I will continue to seek out Rheem reviews.

Other brands to consider are? I think AO Smith makes a hybrid unit? Any other comments? It's shocking how little selection and review/feedback there is out there for hybrid heat pump DWH solutions.

I don't want to consider a split unit...and the split solutions out there are either very esoteric, very expensive (long term ROI) or all of the above. And considerable more installation time/costs. I can install a hybrid HP DWH myself.

Personally... I feel a rooftop Passive Solar tank, augmented by a reliable HP DMW 80 gal is a cost effective easy to install solution. Heating the water up passively before it enters the HP DWH means the inlet to the DWH is already pretty warm and the energy needed to heat it further or keep it hot is minimal. And I just may eventually augment the HP DWH with some sort of passive solution...but for now I'd like to just find a stand alone hybrid unit that is reliable and doesn't cost more than $2500 (hopefully even less).

With the GE, it looks like you'd need to have another unit installed beside the primary unit, for when it unit fails. Kinda like the old joke of needing 2 Jaguars, one to drive and one for in the shop.

The Aergenerate AirTap series is pretty good. It's 2x the cost of a GeoSpring, but should last 2x as long (longer than most of the others too) due to it's all-stainless construction.

http://www.airgenerate.com/

http://nwwaterheaters.com/products/integrated-units/

http://www.gpconservation.com/airgenerate/airgenerate-66-gallon-heat-pump-water-heater-ati66?gclid=CImFt42psLwCFelZ7AodiGEAkQ

Since you can duct the cool-air output of the AirTaps, directing it to another location you can put the water heater where you want it (even in a closet, if that's more convenient) with out concern for over-cooling the room where you place it.

Google "ecotope HPWH" for a set of white papers comparing the specs of different units. IIRC, the rheem had poor efficiency, and the AO Smith was louder and had a wider operating temp range. The GE was in the middle. There were some bad units in the first generation of GEs. They are now in their second generation....check the date on the reviews.

FWIW: I have an 80 gal AO Smith in a coldish garage location where noise is not an issue...and I am happy with my choice.

Posted By woodgeek68 on 03 Feb 2014 07:41 PM
Google "ecotope HPWH" for a set of white papers comparing the specs of different units. IIRC, the rheem had poor efficiency, and the AO Smith was louder and had a wider operating temp range. The GE was in the middle. There were some bad units in the first generation of GEs. They are now in their second generation....check the date on the reviews.

FWIW: I have an 80 gal AO Smith in a coldish garage location where noise is not an issue...and I am happy with my choice.

Thank you for that!

This one has a very good sample set showing how the AirGenerate AirTap ATI-50 and ATI-66 perform in-situ, with enough binned temperature performance numbers to predict how they would perform in the slightly warmer north coastal CA climate.

Thanks both of you for that.

I could install the HPWH in my mechanical room and duct it out, but I have concerns about the noise. Mechanical room is in the middle of the house (first floor) and I would have to go to extraordinary efforts to insulate that room from noise, if I install it there. Outside wall is only appx 12' away from where I could install it, so an exhaust duct is possible.

1. I wonder if I could get away with sharing the stale air exhaust duct with my HRV/ERV system?
2. I am concerned about the negative pressure it would add to a tight house.

The garage is not a bad option, although it will be colder out there in the winter time and therefor the unit would not operate as efficiently at that time of the year. The noise in the garage would never be an issue though. Draining condensate on the garage would be easy too. And it would be appx 15' from my pex manifold in the mechanical room

Many of the bad reviews of the GE units are within the last 12-18 months, but its hard to get a feel if they were installing Gen 1 units or Gen 2 units. I have a year before I have to decide on a unit to purchase, but I need to decide this summer, where it will be installed. Actually I need to decide now, as it needs to be indicated on the plans I submit for my building permit in early March.

Posted By JohnRLee on 06 Feb 2014 09:16 AM
Thanks both of you for that.

I could install the HPWH in my mechanical room and duct it out, but I have concerns about the noise. Mechanical room is in the middle of the house (first floor) and I would have to go to extraordinary efforts to insulate that room from noise, if I install it there. Outside wall is only appx 12' away from where I could install it, so an exhaust duct is possible.

1. I wonder if I could get away with sharing the stale air exhaust duct with my HRV/ERV system?
2. I am concerned about the negative pressure it would add to a tight house.

The garage is not a bad option, although it will be colder out there in the winter time and therefor the unit would not operate as efficiently at that time of the year. The noise in the garage would never be an issue though. Draining condensate on the garage would be easy too. And it would be appx 15' from my pex manifold in the mechanical room

Many of the bad reviews of the GE units are within the last 12-18 months, but its hard to get a feel if they were installing Gen 1 units or Gen 2 units. I have a year before I have to decide on a unit to purchase, but I need to decide this summer, where it will be installed. Actually I need to decide now, as it needs to be indicated on the plans I submit for my building permit in early March.

I put my unit very near my passive solar windows (angled windows with intense wintertime solar entry). It works quite well there. The temps are often above 80F, and sometimes into the 90s. The house is an open design, and it does makes some noise, but not too bad. Plus it generally only kicks the fan on during waking hours, because nobody is using hot water at night. Something to consider. We did build out a small pony wall, with some insulation against the sound. As mentioned earlier, I have a Rheem unit. This installation is about as close as you can get an active solar hot water system with an array, without the considerable expense.

Also, why do you need an exhaust vent. Are you looking at a gas unit? Mine is electric.

Heat Pumps take the heat out of the air, so it usually is inadvisable to install one in a conditioned space unless you can duct the cold air outside, especially in the winter. Since I'm in a climate zone that does not require AC and does require heating for several months a year, my heater would be bucking the heat pump. And my Title 24 compliance report will not allow me to install it in a conditioned space without ducting the cold air out...or I would not be in compliance.

I have spent some hours researching electric heat pump water heaters and seems as though they all have problems when compared to a normal hot water heater. All we can do as consumers is to continually complain to the manufactures about the numerous design flaws. Some of these manufactures are selling crap that should have never been allowed on the market.

Pertaining to there design flaws and their are many, I think they where designed into the product on propose, you will never be able to make warranty claims against these defects unless you enjoy spending thousands of dollars taking corporations to court!

It will most likely take a class action law suit to force them to build the units like they should have been designed to begin with.

What really should set consumers on fire is when a manufacture claims there product is state of the art than discontinues the model only to replace it with another so called newer state of art over priced piece of crap that performs even worst than there previous model. You call them and complain about the unit not performing as well as the previous unit, and they tell you "Well its newer Technology, its going to have bugs in it" Makes you wonder if they even tested the product before mass production.

This is a game manufactures have been playing for decades to keep sales and parts flowing. They call it business/product cycles, I call it getting the old royal shaft.

Posted By JohnRLee on 06 Feb 2014 01:31 PM
Heat Pumps take the heat out of the air, so it usually is inadvisable to install one in a conditioned space unless you can duct the cold air outside, especially in the winter. Since I'm in a climate zone that does not require AC and does require heating for several months a year, my heater would be bucking the heat pump. And my Title 24 compliance report will not allow me to install it in a conditioned space without ducting the cold air out...or I would not be in compliance.

You need some effective passive solar to pick up some heat gain.

Posted By ricky_005 on 06 Feb 2014 09:33 PM
I have spent some hours researching electric heat pump water heaters and seems as though they all have problems when compared to a normal hot water heater. All we can do as consumers is to continually complain to the manufactures about the numerous design flaws. Some of these manufactures are selling crap that should have never been allowed on the market.

Pertaining to there design flaws and their are many, I think they where designed into the product on propose, you will never be able to make warranty claims against the defect unless you want to spend thousands of dollars taking them to court!

It will most likely take a class action law suit to force them to build the units like they should have been designed to begin with.

What really should set consumers on fire is when a manufacture claims there product is state of the art than discontinues the model only to replace it with another so called newer state of art over priced piece of crap that performs even worst than there previous model. You call them and complain about the unit not performing as well as the previous unit, and they tell you "Well its newer Technology, its going to have bugs in it" Makes you wonder if they even tested the product before mass production.

This is a game manufactures have been playing for decades to keep sales and parts flowing. They call it business/product cycles, I call it getting the old royal shaft.

Well you should have researched my way.  I'm 100% happy with my Rheem.

One obvious positive comment I can say about the Rheem line, is if your not satisfied with the hot water delivery system by using just the heat pump they did at less include 2 electric heating elements (Top and bottom of Tank) just like a standard $400 off the shelf hot water heater.  As for their firmware running the whole system, I have no knowledge or experience to say if Reem programmed it correctly or if they have enough sensors to do the job correctly.
Some of these Crooked so called High-End manufacturers (I want mention there names here, (link http://www.youtube.com/watch?v=OSyt-kzGlrA ) only designed in one electric heating element at top of tank. If your not satisfied with heat pump performance Your Luck will run out on this one!

What would be nice is if some of these manufactures started to offer a exotic kits where you have options for higher CMF condenser fans maybe even the option for a stand along fan so ducts can be run further, more complex so you can draw hot air from attic or outdoors during summer months to boost the heat pumps performance. Of course you would need computer controlled dampers and thermostats to know where the best area is to obtain the warmest air and where to exhaust the air based on its air temperature. (inside or outside of home)

Will it take another 20 years for there business/product cycle to catches up?


The Nyle hot water heat pump looks nice .....but there BTU output 6,275 Btu/h needs to be upped, the Reem is at 8700 Btu/h which is quite a bit higher .  The COP efficiency is one of the numbers you have to watch for in all these heat pumps its very a very important spec.

Main question I would like to know is what the true life expectancy of there GEYSER is. I would suspect no longer than a standard high quality hot water heater. Of course water quality has a lot to do with how long your hot water heater last. If you don't replace the anodizing rods when needed, expect your high dollar hot water heater and possibly even the Geyser killing over prematurely.

The idea behind an external heat pump is, if your hot water heater dies prematurely, you only replace the hot water heater. The heat pump water heater manufactures don't like this idea for obvious reasons.
http://water.nyle.com/residential/

Regarding the idea of putting a HPWH in conditioned space and then exhausting the air to the outside - this is generally not going to be a good idea. For example, in my climate (central VA), the average heating season temperature (Nov.-Mar.) is around 44F, but the average discharge air temperature during a typical water heating cycle will be somewhere in the 50's. Sending out 50-ish air and replacing it with 44F air is an energy waste, not an energy saver.

I second the above. The idea of ducting the cool air outside to save energy makes no sense. The air exiting the unit is warmer than the outside air in winter, and exhausting it would cause even colder air to get drawn into the structure.

The EF of these units is ~2-2.3. This implies that the COP of the compressor is probably 2+ on a seasonal average. IOW, they use <50% as much energy as a conventional electric tank WH.

In a heating climate HPWHs do steal some heat from the conditioned space...but in most homes space heating BTUs are cheaper than electric resistance BTUs, so the HPWH is still cheaper to operate than a conventional tank in the winter, just not as cheap as in the summer.

Posted By woodgeek68 on 08 Feb 2014 05:41 PM
I second the above. The idea of ducting the cool air outside to save energy makes no sense. The air exiting the unit is warmer than the outside air in winter, and exhausting it would cause even colder air to get drawn into the structure.

The EF of these units is ~2-2.3. This implies that the COP of the compressor is probably 2+ on a seasonal average. IOW, they use <50% as much energy as a conventional electric tank WH.

In a heating climate HPWHs do steal some heat from the conditioned space...but in most homes space heating BTUs are cheaper than electric resistance BTUs, so the HPWH is still cheaper to operate than a conventional tank in the winter, just not as cheap as in the summer.

If your HPWH is located in your conditioned space and it is summer and 95° outside.

Where would you want to intake air from? ( Inside OR Outside )

Its summer and your HPWH intakes 95° and exhaust 84° and your conditioned space is 72°. Where would you want to exhaust? ( Inside OR Outside )


If your HPWH is located in your conditioned space and it is summer and 95° outside.

Where would you want to intake air from? ( Inside OR Outside )

Its summer and your HPWH intakes conditioned 72° and exhaust 68° and your conditioned space is 72°. Where would you want to exhaust? ( Inside OR Outside )


If your HPWH is located in your conditioned space and it is winter and 25° outside.

Where would you want to intake air from? ( Inside OR Outside )

Its winter and your HPWH intakes 72° and exhaust 65° and your conditioned space is 72°. Where would you want to exhaust? ( Inside OR Outside )



What are the temps differnce of intake and Exhaust air?

I agree. It seems kind of ridiculous to vent an electric water heater. It adds cooling to the air space in the summer. In the winter, it's such a small amount of cool air being dispelled, that it's hardly worth it. In my case, with the intense passive solar, we actually open windows on most winter days, so it's a moot point.

@JimGagnepain

How about some inlet and exhaust temperatures?

I didn't get the impression that @JimGagnepain has a HPWH...but I have one. Here are the numbers mid-cycle this evening...inlet temperature was 67F, discharge was 51F...outside temperature was 36F.

Assuming roughly 300cfm of airflow for the HPWH and the 15F delta-T between HPWH discharge air and outside air, this would be almost a 5,000Btu/hr heat loss. Granted, there would be a small amount (10%?) of heat recovery by the 300cfm of "make-up" air moving through the building enclosure, but at 300cfm the recovery percentage is going to be pretty low.

In JohnRLee's north-CA coastal area (Arcata area) the mean winter outdoor temp is ~47F, the mean summer temp is 57F. There's effectively zero cooling benefit from keeping the cool air indoors in his case, but also no summertime gain benefit to keeping it outdoors, or in an unconditioned space, but it'll still work in an unconditioneds, and deliver good average performance.

COP is much more sensitive to tank temperature than room temperature, but there's a roughly linear COP derating with room-ambient that occurs with falling temperature. The hit in COP from the cooler operating at temps below 60F in winter is pretty small. A tank maintained at 120F that averages a COP of 2.5 @ 75F room falls to about 2.0 @ 60F, but would still be delivering over ~1.7 @ 45F. See the derating curves with temperature of three different units of page 11 of this document:

http://www.bpa.gov/energy/n/emerging_technology/pdf/HPWH_Lab_Results_Advisory_Team_7-14-11.pdf

(The GE unit in the top graph will still deliver a COP of about 2.0 @ 45F ambient temperature with a 120F storage temp.)

Ducting it outdoors would be more of a room-comfort issue than an energy-use issue in Arcata.

* I don't feel that there is much or any advantage to putting it in my home (in the mechanical room). I don't need the negligible cool air in the summer and I would rather not have to listen to the noise it puts out.

* I cannot put it in my mech room (unless I want to vent the cold air outside which might cost more in materials than simply putting the HPWH in the garage) or it will skew my Title 24 report adn I woud have to find other ways to get into compliance (or I will not be granted a building permit).

so it is a moot point.

However, as much as you guys like to bang around and split hairs on this, I'd rather steer the conversation back to reliable brands of HPWH. So many of the self contained units get some troubling reviews. Some of the bad reviews, you can read between the lines. But there are some serious reliability issues for many brands, specifically some homeowners experiencing multiple failures for the same unit. That is a real concern. Given that if it actually fails, you're SOL for hot water until it gets fixed (unless you have a back up unit)

Posted By JohnRLee on 10 Feb 2014 04:23 PM


However, as much as you guys like to bang around and split hairs on this, I'd rather steer the conversation back to reliable brands of HPWH. So many of the self contained units get some troubling reviews. Some of the bad reviews, you can read between the lines. But there are some serious reliability issues for many brands, specifically some homeowners experiencing multiple failures for the same unit. That is a real concern. Given that if it actually fails, you're SOL for hot water until it gets fixed (unless you have a back up unit)

My daughter and her husband went with a GE Geosprings this past summer and have been very happy with their greatly reduced electric bill. They purchased the unit at Lowes when there was a $200 discount as they are running right now and also went for the 9 year extended protection plan for $99.97. I normally don't believe in these plans but in this case with a relatively new product felt it was well worth the $11 per year for peace of mind. Their power company also has a $200 instant rebate so that makes the purchase even more attractive.

The more recent reviews of these units seem to be much more positive than earlier reviews.

YMMV,

Hugh

I suppose in a hot and humid climate it would be best to install HPWH in the conditioned space. One place which might benefit year round is your pantry, by dumping the cool dehumidified exhaust air in the pantry might would help extend shelf life of stored food and if you have a freezer located in the pantry it would help it out also.

Posted By JohnRLee on 10 Feb 2014 04:23 PM
* I don't feel that there is much or any advantage to putting it in my home (in the mechanical room). I don't need the negligible cool air in the summer and I would rather not have to listen to the noise it puts out.

* I cannot put it in my mech room (unless I want to vent the cold air outside which might cost more in materials than simply putting the HPWH in the garage) or it will skew my Title 24 report adn I woud have to find other ways to get into compliance (or I will not be granted a building permit).

so it is a moot point.

However, as much as you guys like to bang around and split hairs on this, I'd rather steer the conversation back to reliable brands of HPWH. So many of the self contained units get some troubling reviews. Some of the bad reviews, you can read between the lines. But there are some serious reliability issues for many brands, specifically some homeowners experiencing multiple failures for the same unit. That is a real concern. Given that if it actually fails, you're SOL for hot water until it gets fixed (unless you have a back up unit)

Consumer reviews in the blogosphere are all over the place (and not always real.) Data is something else. 

The sample set of 30 AirTap units in this study had three (sites 8, 12, and 15) that were mechanically defective and replaced (probably improper or leaked refrigerant charge, or possible damaged during installation), a ~10%  early defect rate,  and one (site 21) failed during the test period (symptoms unclear) and was removed, not replaced, call it 13% early failure.

Of the participants that answered the surveys, 87% were either "satisfied" or "extremely satisfied" with them  nine months into the data-logging period, and 0% reported being dissatisfied.

How that fares relative to their competitors remains to be seen. There isn't a lot of web-whining about this manufacturer, but they probably have yet to ship even 2% of the total quantities that GE has, over several manufacturing years and multiple manufacturing locations (now concentrated in Kentucky.)

I haven't thoroughly searched the NEEA for other field data on other HPWH units. The NEEA has developed a set of requirements for performance in norther climates, and so far only the AirTap and Electrolux units have cleared their Tier-2 bar, so they may be waiting to do similar testing on other units once they're up to snuff on meeting the spec.  The NEEA page with the most relevant links to HPWH characterization can be found here. 

Given the similarity of the N.CA coastal climate to the Pacific Northwest, the NEEA modeling and test data are more relevant than other more generic test data (such as D.O.E. EF tests.)

I've had a first-generation GE "Geospring" since the end of 2010. I've been happy with the efficiency, and generally satisfied with the recovery time (that is, we rarely run out of hot water). It's quite noisy, though. The 2nd-gen GE units are significantly less noisy....certainly not quiet, though.

I've also heard rumors of problems with the first-gen GE units, but I don't have any data.

Over the past 2 years, I've been involved with ~500 units of multi-family housing across ~9-10 locations and ~50 single family houses that have used the 2nd gen. GE unit that is currently on the market. I haven't heard of any major problems. It certainly seems to be the "go-to" model for most folks I work with...mainly due to the reasonable price. Unfortunately, in the apartments they are almost always installed in a small closet with a louvered door or transfer grille. These installs will certainly see lower efficiencies and longer recovery times.

I have also been involved with four single family houses that used the AirTap units...(both 50 gallon and 66 gallon models). No issues at the moment, though Dana's reference of 13% failure rate in a very important demonstration project for the mfr. has me worried.

I agree that a 13% early mortality is a flag that the Atis might not have been fully ready for release to production at that time- that's more like a beta-test kind of defect level. But it's important to bear in mind that those were all from 2011 production(the first year for the fully-integrated units- the had only been selling retrofit heat pumps for standard electric water heaters prior to that) and the sample size was small. The company is still in business , but probably wouldn't be if 13% early mortality were the ongoing failure rate.

The web-whining about GE units is also overblown- design & manufacturing issues tend to get worked out over time- even if the model name doesn't change the issues under the name-plate get resolved, since the cost of warranty replacement & repair is so devastating to both the gross margin & bottom line. It's arguable that GE probably went too aggressively at cost reducing production early-on, and lost some of the engineering-to-production-to-engineering feedback loop on real problems by sub-contracting production in China, but that's clearly not the case today.

I'm sure tiny Texas based (2008 startup) AirGenerate's feedback loop is MUCH tighter, and even though it's company size relative to GE is a spec on the paint of the battleship, it's a more focused company too, without the layers of bureaucracy found in a giga-corporation that can often slow down the resolution of design & production problems. Their problem last year was in ramping up production to meet surging demand, so unless they really screw it up they'll be in it for the long haul (or sell the product line to a much larger company.) They had over 10,000 of the retrofit heat pump units out there by the end of 2010- it's not clear how many of the fully integrated Ati-xx units have sold to date, or how many engineering revisions have been made since the initial production runs. I doubt they're doing their own manufacturing- they're more like an design/engineering & marketing company than a vertically integrated manufacturing company, but they're almost certain to be built locally, near their Houston location.

Dana,

I'm 99% sure the AirTap units are made in China. I'll ask my clients who have one to 2x check.

Posted By JohnSemmelhack on 12 Feb 2014 12:21 PM
Dana,

I'm 99% sure the AirTap units are made in China. I'll ask my clients who have one to 2x check.

That would be interesting to verify if true. 

Given that the founders all have Hindustani names I would have figured India as the most likely off-shore manufacturing location.

Supposedly, this is the manufacturer in China that makes the AirTap units - http://www.theodoorchina.com/1-3-integrated-water-heater.html

Side note - I was recently surprised to see that some Fujitsu mini-splits I spec'd were also made in the PRC. 

Almost anything can be made and made well in the PRC, but whether it's worth the management overhead isn't always clear. GE obviously had issues controlling the supply chain when they went there on this product. I'm surprised that AirGenerate has the kind of volumes to justify that overhead at this point, but they've been growing pretty fast!

I picked one up from Lowes in the summer to install in my house. However, It is too big for the closet the old one is is and I will have to wait and put it in the closet I am building in the additon. So I need to have the thing heated or at least that closet insulate and drywalled. So in the next month or some, whenever it stops snowing / raining long enough to barrow a truck and go to lowes to do the last interior wall.

My $1600 GE Geospring Hybrid HW Heater failed two weeks ago after only 3.5 years of service. This is an early model (Gen 1?) of this unit, as we bought it when it first became available at Lowes. It has run in heat pump mode all this time, so it saved us some $$, but the evaporator coil developed a leak, causing the filter alarm to come on daily. When I called GE they indicated it was a common problem, and sent a new replacement evap coil, dryer and valve. I had to pay a plumber $150 to add extender connectors to the Hot and Cold water lines to obtain enough clearance (5.5") so that the heat pump shell style case could be removed. Luckily, I paid extra for an extended warranty, as it took 2 weeks and cost $250 to replace the coil and recharge the unit. The HVAC tech had nothing good to say about the quality of the GE parts either. But, if it lasts another 3 years, it will have paid for itself. The troubling thing, in my opinion, is that NO ONE in their right mind would pay $1600 for a 3 year rated hot water heater, but that is what I got. And, that is what others are reporting as well... the same failure scenario with a cheaply made evap coil where all the R-134a refrigerant leaks out (and in my case into my home interior). A class action suit seems in order here, as GE has not done the right thing and issued a recall of these early models that are prone to failure. I am posting this so that those who might be considering buying this unit, as we did, to save money and be more green, are aware that at the Ge GEOSPRING hybrid water heaters are made of inferior components; GE knows it but there is only a 1 year labor warranty on this EXPENSIVE unit. I could have bought 5 regular water heaters for the same $. Sigh. Meanwhile, I have posted to the GE Appliances Facebook page and emailed them and gotten no reply. They just want to sweep this under the rug. I will report this to the US Consumer Products Safety Commission, and like others have posted about it on Lowes website and on Amazon.com. As the tech said, before you buy any major appliances, GOOGLE it first... I did not have that opportunity as an early adopter, but you do.

Hi John: My Gen 1 GeoSpring failed two weeks ago. If you get filter alarms that don't clear, be sure to put your unit into STANDARD MODE, so the compressor does not also fail, as the frequent filter alarm indicates that there is a leak in the evaporator coil and it is freezing up on low refrigerant. GE covers parts only under its 10 year warranty. Just a heads up, because this problem can come along suddenly.

Well, it's getting close to crunch time to pick one, as I will be installing it the first week of August. Dana, I know you feel reviews may be skewed, but the GE hybrids continue to get terrible reliability reviews, even on purchases in the last 6 months (or even within the last 2 months), so it's highly possible that GE is has still not worked out all the kinks. Given my remote location, and me not living at the home for several years, I simply can't afford to have issues that I will have to deal with (being so logistically disadvantaged). When I go there to work on the house, I want hot water, and not to have my limited time monopolized dealing with water heater issues.

So I'm considering an A.O. Smith (or Reliance, they are the same units). A lot more money, but their reviews are quite a bit better, and I'm willing to spend a little more money for the potential increase in reliability...even though it is a much smaller sample size of reviews. I am also looking into Steibel Eltron, as they are similar money to the Reliance/A.O. Smith. I have not yet had time to parse through the reviews of the S.E.

Alternatively, I could purchase 2 of the GeoSpring, one for a back up. While that sounds like sarcasm, I actually considered that. But that plan has flaws too. In the event of a failure, it would take me 2 days minimum to switch out the bad unit and have hot water (they take a while to heat the water). When I go out there to work on the house, I plan on asking a local friend to switch on the unit 3 days ahead of time so that I have hot water waiting for me. It might often be 3-5 months in between visits, so not much sense in heating the water during that lag time.

Another thing that impacts my decision, is that I will need to have it shipped to the location. Amazon sells the Reliance and I can ship it for <$200. The units are too tall to fit in my trailer and I''m not keen on strapping it in the bed of my pick up. They cannot be transported laying down on their side. Must be kept upright. I'm not sure if that is because of the coolant or compressor oil (or both). My trailer is only 60" tall inside but the opening is 59".

Obviously, whichever brand I decide on, local repair will also be a factor. So I need to check on warranty repair ofr all 4 brands (GE GeoSpring, Reliance, A.O. Smith & Stiebel Eltron)

I purchased one last year with full intent to install it in a month or two. My addition turned into a big project and it has been sitting in the box. I will get to it. I am looking forward to installing it into a large closet with home network / server equipment so it can draw the heat off the PCs and heat the water. It will also dehumidify at the same time. Seems like win win. Should last longer than one of those little tiny ACs. Considering the closet I have the stuff in now is smaller and does not have AC it should be fine and not overheat.

Well just got back into KS from No Cal. I was there for 3 weeks, working on the house. I installed a Manabloc plumbing manifold, 2 breaker boxes (sub panels from the main meter panel) a toilet and some rudimentary power and plumbing. We (my college age son and I) were basically camping in the house, while we worked.

Since I didn't want o haul the water heater upright in the bed of my pickup from Kansas (you shouldn't lay a heat pump water heater down for long periods of time and it would not fit in the trailer standing up), I opted to purchase the GE locally in NoCal and install it.

It was the first thing I did, so we could have hot water (and showers). I must say, they thing performed beautifully in the 3 weeks we were there...so far, so good! It never flinched once. Time will tell but since I won't be moving in the house anytime soon, it may be a while (out of warranty) before it gets a long term acid test. But for now, I give it a thumbs up. I shut down power to it (and turned off the main water supply to the house) before I left. I will have a local friend that lives a mile away, turn it back on for me a few days prior to my next trip there, so I'll have hot water when I arrive. Eventually I will be able to remotely turn it on with my automation system, but I am still waiting on the local internet provider to pull service to the house.

What about the RHEEM unit?  I realize that is what the first post was, but that was also 2 years ago and I'm pretty sure it has been updated.

http://www.rheem.com/product/water-heating-heat-pump-professional-prestige-series-hybrid-heat-pump

One of my concerns with the Rheem is it is 50 gallon, not 80 gallon which both Stiebel Eltron Accelera and AO Smith Voltex are available in 80 gal. 

One more thought... The AirTap ATI's cold air can be ducted.

Not sure if this would work but could we vent the cold air outside during the winter and open a vent to bring it inside during the summer? Might help save a few bucks on cooling the basement and then trying to keep it heated...?

ould we vent the cold air outside during the winter

Where would the replacement air come from?

Good question,  it'd probably get sucked through cracks... but wouldn't it be similar to running your clothes dryer?

Venting cold air to the outside and having this cause infiltration of cold replacement air is, under many weather conditions, not a win. Agreed, most cloth dryers aren't an energy win either (although some type of lint proof HRV could fix this).