We've been gathering quotes for the HVAC portion of our build and trying to decide which way to go.
It is so hard to figure out who's is right. If an HVAC contractor does not do Geo, they try to talk us out of it, saying that for our house it does not make sense to spend all that money and that an air source heat pump will be better.
If they do Geo they try to talk us into it, saying we'd be sorry if we don't go with Geo. I'm hoping to get some unbiased opinions here.

Here's our situation - building 3800 sq ft. new house, heat loads from three different companies are in the 42K to 50K range for the whole house heat and 36k cooling load (and that's with R40 in the attic, though we'd like to go R60+) Our fuel is electricity at $0.048 for heating and $0.065 for cooling (our other option is propane, but right now electricity is cheaper than propane)

We do have radiant in the basement, and ideally I wanted radiant in the whole house, but it is about $27K to do radiant heat in the whole house if we put the labor ourselves
with hiring the forced air A/C conventional system. (Hi-velocity would be an additional $8K)

We can do just the basement with radiant (labor ourselves) and forced air upstairs for heat/cool for $18K with a heat pump, and we have three quotes that are all in the same price range.

We got a quote to do geothermal with Hydron Module 5 ton system for $34K forced air upstairs with a 1 zone radiant in the basement (or he could add zones for an arm and a leg) and he does not need to do heat loads.
Another quote for 45K to do forced air upstairs and add $5K for radiant in the basement with a 4 ton Trane unit
And another for $28K for a waterfurnace 3 ton just forced air for the upstairs (we'd do the radiant in the basement ourselves for $6K with a boiler but with zones and it is being designed by NRT).


I'm talking to the waterfurnace guy about using the Synergy 3D and hook up the basement radiant to it, but don't have numbers on that yet. The waterfurnace comes "closer" to the heat pump quotes when you take the 30% tax credit. So which way should we go? Does spending the extra $6K to put in a geothermal make sense for us?
I'd like your input, discussions, and advice. Thanks.

Where are you located?

Have all bidders give you operating cost projections to help in your decision.
5 ton geo is awfully large for the load mentioned.
Good Luck,
Joe

I like the idea of a Synergy right-sized for the cooling load, and feeding the radiant, buttressed by an additional source of heat for the coldest days. If you are building your dream house (planning to stay in it a long time) anywhere north of I-40, go for the maximum radiant option.

If it is your forever dream house consider that Propane may also support goodies such as a quiet and reliable whole house standby generator, gas grill, fireplace log lighter, etc. I sprung for all those things and am glad of it.

HeimDm - I'm in Iowa

Joe.ami - only the Waterfurnace guy did. Yes, I thought the 5 ton was oversized, and he said he was actually sizing it for 0 deg. outside temperature (though he doesn't do actual heat loads), and the rest with aux. heat because otherwise we'd need an extra loop.

Engineer - when you say geo sized for the cooling load and feeding the radiant, you mean feed the whole house radiant or just the basement radiant and forced air upstairs? Additional source of heat, you mean like resistant strips for aux.? We will have propane ($1.50/gal) for a gas fireplace and my range (I like to cook on gas better than electric) and I am dreaming of the goodies like gas grill, generator, etc. We'll also have a wood fireplace in the basement that is our emergency heat during power outages in the winter.

As mentioned the cost of operation will help lots for your decision.
I love the geo concept ,but if your house is all icf or sip, I doubt the return on investment is there.
I am in the finishing stages of my own build (icf to roofline) and putting money in the envelope was by far the best choiceI've made so far.
I had to check on the furnace from time to time when it was first installed just to make sure it was still running.
Couldn't belive it and still. Doesn't run very long either. Just my 2 cents.

By all means use the maximum potential of the sized-for-cooling system to feed whatever radiant you have.

$1.50 propane is enviable - I paid $3+ 2 years ago to fill my 1000 gal UG tank.

Sounds like you have plenty of backup sources.

If I lived north of I-40 and I was building my dream home it would have radiant floors wherever feasible heated by the cheapest means available - $1.50 propane would figure into the mix

Joe.ami - only the Waterfurnace guy did. Yes, I thought the 5 ton was oversized, and he said he was actually sizing it for 0 deg. outside temperature (though he doesn't do actual heat loads), and the rest with aux. heat because otherwise we'd need an extra loop. ....

I would run away from anyone who does not do a load calculation. What's more any operating cost projections are garbage without a real heat loss calculation. Certain things ratify someone as the real deal in the HVAC world. Manual J calcs are among them.

"I love the geo concept ,but if your house is all icf or sip, I doubt the return on investment is there.".....
Curiously the opposite could be said; "If you have geo I doubt the ROI is there for SIPs"
As there is more than one way to skin a cat, all are worth researching. A hypertight envelope requires less maintenence than any heat plant but is often more expensive to purchase. ROI is often longer term so time in the home matters as well. My geo may have a payback of <5 years against fuel oil for instance that won't be true of SIPs.
Folks should educate themselves on both.

"$1.50 propane is enviable - I paid $3+ 2 years ago to fill my 1000 gal UG tank."
That's the whole point isn't it? Propane hit $3.00/gal two springs ago and $1.10/gal last summer. It is very volitile as it comes from foreign sources. Given that our country is borrowing money like a drunken sailor, it is unlikely the dollar will stay strong enough to keep propane at $1.50/gallon.
Electricity coming from domestic sources........
I know everyone here knows this, but OP may not have been in the propane market 2 years ago.
j

If they didn't do a load calculation, I would tell them you require one be done (and give you the results - doesn't hurt to ask). If they won't do one, then I wouldn't consider them.

Our installer correctly "estimated" (no manual J) our system sizing. I asked him to do one, and he did it without question. His results were similar to most of the other quotes we received (except for the 1 incorrect manual J from a different installer.) He had lots of experience in this area (region). I'm not suggesting that a manual J isn't needed - in fact I insisted that every installer that quoted us do one. Just wouldn't want someone to discount an installer unless they refuse to do one. If I discounted our installer for not initially doing one (I know, he should have), we would have had to go with someone else, and not with the installer we really liked (after checking references, etc.)

thagreen - yes the comparison probably will help, but if they don't do them then what? Do it myself? And the one from WF that gave me one compared it to propane. That would work if we were even thinking of propane in the new house for heating. I'd like to compare geothermal for our house against an air source heat pump with aux resistant strips or even an all electric furnace.

Engineer - I talked to the WF guy and in his analysis it is a 38K BTU Envision unit with a 5 kW element based on 46KBTU/hr heat load, and it says that the WF unit would handle 96.7% of the load and the resistant strips would do the rest. I tried to talk to him about switching to a synergy and hooking up the radiant to it, and he said he prefers that the radiant be handled by a boiler, and said that I do not need to go with radiant upstairs. That with geothermal the comfort comparison between radiant and geo forced air is the same. He also said that if we went with whole house radiant, we'd need the 4 ton unit and add an additional loop because to do hydronic he needs to size the unit for the whole 46K load. He also said that we need to keep air moving in the winter, so might as well just go with forced air. To me this doesn't make sense, so maybe someone here can explain it to me, why he can quote me a 38K model with 5Kw Aux to do forced air upstairs and handle the radiant in the basement, but to switch to whole house radiant, we have to upsize.

joe.ami - yes, the guy without heat loads is no longer in the running. I did ask if he would do them, and he answered he just doesn't do them, he's installed so many systems and no one has complained, blah blah. I think at that point I didn't hear another word of his presentation.

We have ICF basement, and framed main floor, so the SIP issue does not apply to me. But we are paying $$ to use spray foam because we want to minimize the infiltration and we're shooting for R30 in the walls and R60+ in the attic. So I'm back to the same question, how can I compare geo vs an air source heat pump for our situation to see if that additional $6K investment is worth it?

And yes, I've been in the propane market, and the way they do contracts here you lock into your rate in April for the next year. We were in that boat of stuck with $2.50/gal of propane that we contracted in the spring, while the winter cost went down to $1.80 that winter. Hence why we're staying away from propane as a fuel source. If electricity goes up, I can add solar panels or a wind turbine to my farm (which I'd like to be off the grid anyway if I could).

Geome - yes, I ask and most seem to do it.

One guy refused to give us geothermal quotes because he is convinced the investment is not worth it for our house. It is frustrating when you want a contractor to work with you on options, and some get testy if you try to get them to look into doing things a bit different, so they give us an outrageous quote just to let us know they are not interested.

I thought the installer's software will allow comparisons of various equipment including air source heat pumps. Pros, is this correct?

The warm air geo is designed to meet 100% of your load, but it uses electric resistance to meet the maximum requirements. The same can be done with water source but it is not done with an electric duct heater for a few bucks. There are lots of ways to do this, but sounds like WF guy may not have hydronic experience.
Where are you located? A pro in central OH who specializes in geo hydronics and assissting DIY travels quite a ways.
J

I don't understand why radiant couldn't just as easily be supplemented with a few kw of resistance as can air source.

Posted By engineer on 26 Feb 2010 10:27 PM
I don't understand why radiant couldn't just as easily be supplemented with a few kw of resistance as can air source.

Of course if the requirement is a few K that will be true of water or air. My point was if you wish too supplement the hot water production, it will not be as easy as installing a $200 duct heater. If you wish to supplement the radiant system with warm air, then it is as easy as installing the duct heater.
J

Would be worth it to buy an energy analysis program and run different scenarios with better insulation, triple glazed windows etc. You input the size of your windows, home dimensions etc & they will give you an estimated btu load. You may find that even more insulation will be worth it. I was working with an energy engineer on house plans for a 3500 SF ranch with finished basement; he calculated we'd need two minisplit air conditining units as the load was about 25mbtu. REM design is one I use - it was under $300. Then you have some idea what you need; it wouldn't take the place of a professional design, but it will help you shop for the best value.

yes. One option is HVAC-Calc. It costs $50 for a 60 day temporary license intended for DIYers

Because of the Fed and State Tax Credits (until 2016) right now, the energy rater I have for my project (W-NC) said I'd be foolish NOT to go Geothermal.  I had my wells dug this summer (lot is small, I had to go vertical).  Though a GEo system upfront is much more than a heat pump, after Fed and State (65% combined) tax credits, it will cost $2-3K less!  My home is a whole (wall and roof) SIP  6.15" design (R-40), 3,500 ft in the mountains, can be cold and frequent power outages.  Will probably have propane generator as backup, as it's shrouded in clouds so much in the winter solar panels might not be right mix.

Posted By martyrh on 02 Mar 2010 04:35 AM
Because of the Fed and State Tax Credits (until 2016) right now, the energy rater I have for my project (W-NC) said I'd be foolish NOT to go Geothermal.  I had my wells dug this summer (lot is small, I had to go vertical).  Though a GEo system upfront is much more than a heat pump, after Fed and State (65% combined) tax credits, it will cost $2-3K less!  My home is a whole (wall and roof) SIP  6.15" design (R-40), 3,500 ft in the mountains, can be cold and frequent power outages.  Will probably have propane generator as backup, as it's shrouded in clouds so much in the winter solar panels might not be right mix.

You get a 65% deduction/rebate? That's amazing! I've done a number of analysis in my (Eastern PA), and in a modestly sized, tight, well insulated house, a properly sized two-stage air-air heat pump makes a lot more sense than a ground source heat pump. Yearly operational cost differences for a 2000 SF home were typically only $200, with GSHP about $450 and conventional about $650. The devil's in the details with these things. The most important thing a person can do is get an energy audit and attack the duct leaks, infiltration problems and insulation problems to make their home more energy efficient. Spending a few thousand there can cut utility use by 20%-50% to start with. Once you do that, the cost savings of geo vs. other technologies diminishes accordingly. The other thing I have to emphasize is for people to really check their duct systems. Most homes I evaluate have ducts that leak like crazy, and installing a high efficiency forced air system that is battling 30-50% energy loss through duct leaks is just plain stupid.

" Most homes I evaluate have ducts that leak like crazy, and installing a high efficiency forced air system that is battling 30-50% energy loss through duct leaks is just plain stupid."

That depends entirely on where the ducts are.......
In my area unfinished basements are common and while people don't want them at 70* they don't want them frozen either. Duct loss was commonly employed to temper these spaces as the load is modest. To seal up every last joint and then cut a hole in the duct and add a register to heat the basement is a 0 net gain.
Duct sealing makes much more sense to me in attics, crawls or basements in cooling dominated climates.
Code now requires the sealing of joints.
j

What about a 3 ton geothermal heating the radiant floor downstairs, (plus perhaps a kitchen/bath floor upstairs?)and the same 3 ton also cooling the upstairs via a water coil in a cheap electric furnace which supplies the little additional heat you will need for upstairs. If you run the furnace fan in the winter, and keep the floor downstairs toasty, you can get good efficiency, cheap ground based cooling, etc.
Of course you will have to price this out, etc. You might want to consider whether to put the ducts in the ceiling or floors. Heat rises. Cool air sinks.
You need a woodstove if power outages are common. Or a very expensive generator so it does not burn out your compressor, as you need a lot of power to start a compressor. Also 5 ton compressors are at the limit of single phase power. Your power could very well be lower quality - a 3 ton unit might be more robust.