Looking for some advice.  I am hoping to install either a traditional geothermal pump 'n dump or a high efficiency Acadia air to air heat pump this fall.  I don't know too much about either system, but I know that heating my 2500 sq ft home in Michigan on our propane furnace is going to hurt the pocket book.  I'm not a DIY, so I'll be paying the entire bill.  Anybody have experience with the Hallowell International Acadia heat pump?

Not familiar with that particular model. All heat pumps are limited by having to move air outside. In MI (where I and Joe AMI are) it gets to cold for at least 2 weeks in general for the heat pump to operate. You'll still need propane for the 2 coldest weeks, and if you're buying less, the company will give you a worse rate per gallon.
Joe and I looked at the payback for it. In my particular case, it was a 5 ton heat pump was $4000 and saved 1,000 a year. ~20,000 a year for a geo system paid back ~5,000 a year, so the payback period was pretty much the same, but afterwards, the geo system continued saving a lot more.

Acadia is a multi stage air source heat pump and the problem as always is when it gets really cold out how do you want to make up the difference?
I don't have a problem with ASHP's, I just don't think they belong in a conversation about geo. There's really no comparison.
Joe

I used to heat my 2,600 sf home with propane. I live in central PA and my propane bills were about $3,000.00 last year. That was enough for me so we made the switch to geo. I have a Climate Master Tranquility 27 with a closed loop (3-200' wells). My installed cost was around $20K which included, the wells, the unit and installation, rezoning my basement and hooking up the desuperheater. It also included hooking up my gas grill to my 500 gallon buried propane tank. I will never run out of flame in the middle of a steak!

I consistently burn 950-1000 gallons of propane each year. With propane costs going up all the time my payback period was under 5 years. I'm sure you can't go wrong with a good quality top of the line geo unit in the long run.

I mildly disagree with you. My contractor has just installed, but not yet fired up, a 3 ton Daikin heat pump in my under construction ICF house. The reason I chose this heat pump is because it will extract heat from outdoor air down to 10F with a COP of 3 with the capacity I need. The Manual J design temp for my location is 9F. The max heat load for my house calculated out at about 36,000 Btuh. In my case the Daikin heat pump accomplishes the same thing as a geo source heat pump, i.e., heat production with a great COP throughout the entire heating season with an output level quite adequate. The installed cost is thousands less. It won't be quite as efficient as a GSHP, but it's good enough for thousands less, and it avoids having me depend on electric strip heat, the usual killer of overall efficiency of an ASHP.

Another heating contractor nearby installed about a half dozen Daikin systems in this area last year. One of their representatives told me not a single one had to switch to auxillary or back up heat this past winter.

So, in an appropriate climate the Daikin will deliver efficiently produced heat for the entire season, just like a GSHP. So there is a place for some ASHP systems in a conversation about geo if they are a viable alternative to a GSHP.

Will you have a way to measure actual COP?

dmaceld, I hope your system works well for you. Our experience in MI, is that systems installed for thousands less, save you thousands less. And as the savings is geometric.... By the way your 36k BTU unit will deliver <30K on a 10 degree day. If that's enough, you must have serious insulation, which is great.
Every system has it's place. Daikin has some exciting possibilities and Senecarr can tell you that we looked at one of their products at his house, but only where there was no existing duct work. In every instance, operational cost calculators favored geo. No matter how you slice it a massive (albeit expensive) underground geo heat exchanger, will always prevail over small air source heat exchanger's if all other things are equal. Don't confuse savings on duct installation as savings on equipment.
I maintain the two are not an apple to apple comparison, but appreciate your efforts to disagree with respect vs antagonism and hope I've accomplished the same.
Regards,
Joe

I agree with both comments. As you know the Manual J design temp is the lowest expected temperature 96%+ of the the time. The heat load for my house at that temp is about 36K Btuh. Here in SW Idaho the 30 year historical temp data shows we have hourly temp readings below 20F only about 10% of the heating season. At 10F I may have to go to supplemental heat, which for me will be a pellet stove! But then on the other hand the ICF construction may very well "fly wheel" me past those low temp hours. 80 to 90% of the heating season the heat pump will have capacity above the heat load. If I remember my calcs correctly the heat load is only about 24K at 30F. In designing a heating system I believe one should look at the economics of under sizing the system with appropriate back up and peaking for the low percentage of time the weather is actually near the the design temp.

Not that my opinion matters, but I see ASHP's as the step between a traditional furnace / AC and full geo system. For 95% of the time they are more efficient then a traditional furnace and I doubt the 5% of the time adds up to make it less efficient over the year. My sister in law has a 10 year old home, they don't have space for a field (living in a city lot and aren’t allowed to do vertical) and their furnace is going to cost more to repair then its worth. So I suggest they look at ASHP's, it sure seems like a better deal then another furnace.

Looked at the Daikin with Joe. It's low operation and ability to use variable refrigerant so you can add to the system is interesting.
I'd still much rather in my climate see them apply the variable refrigerant technology to a geo system, doubly so with tax credits they are enacting for geo systems.
Of course all of the installers on here are perfectly understanding of proper sizing (not undersizing). Almost every system is designed to meet 90 to 95% of maximum need and boost with electric coil for the rare times. Unlike an ASHP, it would be possible to have geo operate for 100% of the lowest requirement, but the additional tonnage would always be uneconomical.

I am about to have this system installed in my Victorian home in downtown Toronto.  Our weather is similar to Michigan's, and I will not require a back up system with the Acadia.  This unit qualifies for energy efficiency rebates in Canada and the energy auditor I used said they've had no problems with the unit, and it does work.  She said the company is very reputable.  The big deal here is the price difference.  $18,000 for the Acadia 2 ton system (2000 sq. ft.) vs. $40,000 for a 2 ton geothermal system.  (GT would require vertical loops in a small space = big $$ for install).  The Acadia is not quite as efficient as geothermal.  I have the option of intstalling a secondary heat exchanger off my tankless hot water heater if I find I need back up heat later.  Also, at this point, the Acadia doesn not provide domestic hot water as a benefit during cooling season, but there is an air to water system that does ("the cube", same company).  I imagine there will be a way to provide hot water off the Acadia at some point, but don't quote me.  According to the company they have installs in Alaska, and the unit functions at 200% efficiency at -30 celcius. (about -25 F).

If you're worried about back up heat (say your temperature dips well below -15), I would have a secondary heat exchanger installed on a loop off your hot water.   This would be cheaper than doing electric resistance as back up.

A caveat:  adjust the temperature by one or two degrees at a time.  Reason is, if the load called for is high, the units (geothermal included!) will activate the back up system to suppliment.  I know this for a fact as my sister heats her 6000 square foot home with 2 geothermal units.  Very cheap as long as the supplimental source is avoided.

I hope this helps.  Good luck!

We are currently in process of finishing a home that the owner had a Air to air installed.  The installer is shady to say the least and was not recommended by any of the subs.(different story)  The utility co that they are on gives them a break if installed on a separate meter. ( .058 per kw! ) It is running on average 175kw per 24hr period!  This it with the house set at 60°. New construction, 1" spray urethane on the walls, upgraded ceiling. 4000sqf heated in Central WI.  I can heat my home (72°) the same size for half that on NG and my system was 1/4 the cost.  YMMV it's very possible that it's a bad install!

everything I have read about these cold climate heat pumps ( basicly 3 stage , 1 two stage compressor and 1 booster compressor )
Is that they use a noteable amount of power above what is advirtised
While they are not rated by ari
there are somebody that ran the ari tests on them and found
lower air temps then advertised
more power then advirtised
lower cop
and some dependability issues ( could be isolated )

I think the VRV technology mini-split systems are awesome! And so is the technology. But, I don't think they can compare to eff. delivered by GEO. It's actually a very difficult comparison. Complete engineering data is tough to come by on these systems (I haven't seen data for all outside air temps). Plus, if there are say 4 indoor ductless units running off the same condensor, is the amp draw on these indoor units included in the COP (albeit very small)? Is the defrost time that's required in 20 degree weather calculated into the COP measurement? I saw one piece of data that said 8-9 minute defrost time. That could be required every hour? They're still running compressors and back-up during defrost.

I'm not bashing the air-source mini-splits, I'm just saying the performance comparison is VERY difficult, and somewhat subjective. Many systems probably operate more eff than GEO in cases where the ductwork systems leaks 400CFM. Zero ductwork is a huge plus...

One thing nobody has brought up is the life of the compressor. Typically, air source heat pump compressors don't last as long as geo. 10-15 years expectancy on air to air, and 20-30 yrs. expectancy on geo. Not that this is always the case, but it's something to consider, too.

First off, Daikin doesn't publish COP. Their data tables list power in and MBtu output at various temp combinations for the condenser. The power in number includes compressor and fan. The data for the indoor units gives only one power input value, which I believe is at max fan speed. I took the data for the 3 ton condenser and 3 ton indoor ceiling duct mount unit, which is what I have, and produced three charts showing power in, heat out, and calculated COP for 72° indoor temp plotted against outdoor temp from 5 to 60°F. It's attached. The third chart is the same as the first with the 497 watts indoor unit power added in. Interesting how that changes the COP number. I also have a 9000 Btu wall unit in the garage which isn't included in the charts.

Defrost is a different animal with Daikin. First, it defrosts only when needed as determined by system temps and pressures. Rate of frost buildup is dependent on temp and humidity. The only time I've seen any real frost buildup on my condenser was when it was foggy, raining, or snowing, and below about 25°. There is no backup in the Daikin system, so during defrost there is no heat output. I've observed my unit putting out heat from the garage wall unit with the outdoor temp below 20 on a foggy day and the frost buildup so heavy you couldn't see the coils! Not surprisingly, it went into defrost not long after.

You're right, it is difficult to get an accurate COP number for the Daikin because there are so many variables at play. My COP charts don't account for defrost time because it's so variable. The defrost time is, as you say, about 8 - 10 minutes, but it certainly is not every hour! Not with my system anyway!

I did make one mistake though and that is an application error. I should have used a 12 or 18 KBtuh unit in the garage, even though the heat load calc came out at only 6 to 8 KBtuh. That's because I plan to keep the garage around 55 to 60°, or cooler, and warm it up when I want to work out there. After I sized the system, working with my HVAC nephew, I added an AirTap heat pump unit to my hot water heater. That adds a fair amount to the garage heat load. It turns out the garage unit is running many more hours than does the house unit, and it only puts a max demand of about 25% on the condenser. The house heat is supplemented by human activity and solar through the windows and the garage isn't. But the condenser power in bottoms out at about 6000 Btu anywhere below 50% load. If my garage unit is idling just keeping up with heat loss, which is about 6000 Btuh I have an effective COP around 1. Not what I planned on! I have a pellet stove sitting in the garage now for supplemental heat so I can keep the Daikin running at a minimum but I haven't decided for sure if I'm going to install and use it. Had I used an 18 KBtu unit in the garage then I would have good efficiency when it is running by itself and in conjunction with the house unit. But, on really cold days I would have 150% load connected to the condenser and the house unit wouldn't be getting 100% of the condenser output, just when the house needs it most.

This is the first Daikin system my nephew has installed, and the distributor in Boise has been selling them for only about a year and half now. This is the first time anyone around here has installed a system with my configuration. We're all learning how to best utilize the Daikin system!

I'll be the first to admit that even the Daikin air-to-air won't compete head on with geo for efficiency, but from what I can see it is a viable option for the cases, like mine, where the heating/cooling load for a house is 50,000 Btuh or less. But one has to really think hard how to best handle two disparate heat load requirements with one system. They supposedly are working on an air-to-water system but UL certification is a hang up. That would a sweet system IMO. Run the heat pump at its most efficient point to heat water in a storage tank, and then portion that stored heat to the house as needed.

One good thing about the Acadia is it is assembled in Maine.  I wish I knew where their compressors are made because I have absolutely no faith in Chinese compressors.  Remember when refrigerators used to last 40 years or more?  The company (I know, they have a bias!) is projecting a 20 year life expectancy, similar to high efficiency gas furnaces.

Again with the higher costs than expected, gentle changes in set temperature will not activate stage 3 heating or back up heat.  Therefore adjusting 1 or 2 degrees at a time will result in savings over having the thermostat go from 65 to 72 all at once.  Like driving your car, you'll burn less gas if you don't floor it at every stop light, and you'll still get there.  For most applications, stage 3 heat is not required most of the time.

My system is being installed the first week of March.  I'll let y'all know what my experience is after that.

Rcg, your point about small lots making ASHP's is valid. But depending on gas or electric rates pay back for your 18K could be long term as well. Curiously that kind of money could get some one into GSHP in larger lots that permit horizontal installation.
I hope the initiator of this thread didn't try a tight sized ASHP in MI this winter he'd be disappointed. More so i hope no one in MI or anywhere governed by the International mechanical code puts a pellet stove in their garage, they might be in for a surprise if they try to sell or worse yet try an insurance claim if there's a fire.
Right now in the U.S. there's going to be little reason to pick ASHP's over GSHP's with tax credits available.
I mentioned recently that we're looking at ASHP's for some situations, but they've a little ways to go before I don't feel like we're settling for the 2nd best.
I guess that's what disturbs me about the new ASHP marketing strategies is the pretense that they are "as good as" GSHP's.
J