Hi,

I have been lurking and reading as much as I can on this forum for the past month while waiting for my geothermal estimates to come in. Some background:

We (family of 5) live in central PA in a 4000 sq/ft home from 1873; currently we have an oil furnace for 1st floor heat and all hot water, 2nd floor is electric baseboard. Our oil and electric bills in the winter are horrendous. We got an energy audit December 2010 which confirmed the fact that we are woefully underinsulated. We have plans to seal/insulate the attic; blow insulation into the walls; and seal the basement which would potentially take us from 143.2 kbtu/hr to 61.4 kbtu/hr and reduce air infiltration by 40%. We hit a roadblock on our insulation quest when every contractor recommended installing our HVAC system before insulating the attic so their work would not be disturbed. So we got estimates from three geothermal companies (sorry if some of this info is useless, I am just copying from the estimates):

#1 has been in business since 1974 but only doing geothermal for 8 years. They have installed 9 in the last 2 years. They recommend a  4 ton Carrier Geothermal System Model 50YDV for the downstairs and a 3 ton split system for the upstairs, including programmable thermostats, 15 KW heater for downstairs, 10 KW for upstairs, hot water generator, fiberglass ducting, 80 gallon tanked electric water heater. Vertical closed loop, I believe he said 3 wells? Total cost: $47, 500  Extras: Steam Humidification for $1075, Dual Bulb UV Germicidal Lamps $925, and Electronic Air Cleaner for $995. (Do I need any of these? I already have UV lights on my water softener if that matters.) Estimated Tax Credit/rebates $14250 (does not include if we opt for extras) Net price $33250

#2 has also been in business since 1974 but has only done a handful of geothermal (including his own home). They recommend a 4 ton 2 stage ClimateMaster TTV049 with 20KW backup heat for the 1st floor, and a 3 ton 2 stage ClimateMaster TTS038 with 15KW backup heat for the second floor. He uses metal ducting and would include a 50 gallon preheat tank as well as connecting our already installed hydronic floor heat in the kitchen. Vertical closed loop, 2 wells 400' each. Total cost: $49, 252  Estimated tax credit: $14775 Net price $34477

#3 has been in business since 1986 and geothermal is all they have ever done. They have installed upwards of 300 systems. They recommend a 5 ton WaterFurnace NDV064T dual capacity w/410A refrigerant, ECM blower motor, desuperheater, Aux Heat EAL20, electrostatic air filter, insulated duct board and flex duct, 50 gallon water heater for preheat tank. Vertical loop, heat fused polyethylene pipe joints, total pipe 1500 feet plus header. I believe they also said 3 wells? They have also offered as extras that we will probably take, a 2 zone control system and the Senergy unit to include the in floor heat. Total cost with these extras: $28, 941  Estimated tax credit $8682  Net price: $20,259
 

Cost-wise and experience-wise option #3 seems the best, but there is that pesky question of why they recommend one 5 ton unit and the others recommend two units totalling 7 tons. #1 and #2 said they would NEVER use one unit in our house, that they would be concerned about it being stressed too much, running all the time,  and not doing a good job heating or cooling on the 2nd floor.

I appreciate any advice you can offer! :-)

I'd take option #3.

Reasons:

Looks like they have good experience and the system is pretty modest.

You'll be motivated to do those energy upgrades and insulation projects because the capacity of the single unit is less than what you need right now, before insulating. Aux heat can probably get you there temporarily.

It would be nice to just have one unit to maintain/worry about instead of two.

#3 is also $13,000 less than the other two. If your upgrades don't turn out quite as well as expected, $13,000 in savings upfront buys an awful lot of auxiliary heat for a long time.

If it turns out that the single unit is really unsatisfactory, you could always add a ductless minisplit for the upstairs at about $8,000 and still have spent less than either of the other two plans.

Thank you for the reply. I wondered if the other two estimates were planning for the house we have now rather than the one we will have; I gave them all the same info, told them exactly what we are planning to do and gave them the projected numbers, but two came up with 7 tons and the one with 5.

I forgot to mention the other reason two units were recommended--if, say, the upstairs unit breaks down, we would still have heat/cooling on the 1st floor for comfort. With one unit, if there is a problem, we are out of luck.

I will be calling #3 today to discuss the other estimates and find out why they are the only ones to recommend one unit.

Even the 5 ton is heavy for your load, but defensible. 7 tons shows a lack of product knowledge and confidence.
1 unit is prdeferred over 2 in every instance.
If you are worried about heat if unit breaks down, leave existing unit and electric baseboards in.
Good luck,
Joe

With one unit, if there is a problem, we are out of luck.

The great majority of homes have only one unit. With a new Water Furnace you should have a very reliable heat source. If something goes wrong, you can get it fixed.

Keeping the oil heater might be feasible, but before you count on keeping the baseboard heaters you might want to confirm that your electrical service can support the new equipment AND the old baseboards. It's pretty gratifying to throw out old baseboard heating.

Disclosure - You can see from my signature that I am a homeowner with a geothermal system (2 in fact). You should know that ICFHybrid has no geothermal experience since he gives geothermal advise and opinions without disclosing this fact. Enough said.

I agree that one system is best and the experience of #3 seems very good. You want to do this once, and have it done right the first time. I would ask #3 what type of performance, comfort, or other guarantee he can offer you. I would ask for many references including ones that have systems with zoning and the in-floor heat if you choose these options. References who own older homes may also be valuable to your research. Call all references and ask lots of questions. :-)

Best wishes.

Yes, I realize most people only have one--I think living in San Antonio previously, where it seemed like most newer 2 story homes had two (for cooling purposes, obviously), I got that stuck in my head.

if I am correct, 12 kbtu translates to 1 ton--so 5 tons is slightly low for our projected 61.4? But 7 tons seems like overkill--maybe they are projecting we won't get that low?

We are planning to rip out all the baseboards (for the upstairs electric and for the oil/hot water)--we want to be off oil completely!

I have read good things here about WaterFurnace, so that also inspires confidence.

Posted By ICFHybrid on 04 Feb 2011 08:26 AM
Keeping the oil heater might be feasible, but before you count on keeping the baseboard heaters you might want to confirm that your electrical service can support the new equipment AND the old baseboards.

Of course....If you intend to run the electric baseboards at the same time as your 4 times the efficiency heat pump.....

I will certainly check references--I already have one from #3 but will get more.

The other thing I have some concerns about is the size of the water tank--we are a family of 5 with one teen boy and two who will be there soon--everyone loves hot showers, some of them quite long...should I ask to upgrade to an 80 gallon tank or should the 50 be sufficient?

Geome, I see you have two systems though you indicate one is best. Are there some situations where you just can't get around it or where two are preferred?

With a family of 5 I think the 80 might be a sensible upgrade.

There are situations where you can't get around 2 systems. IMO it is never preferred.
J

Good question. Our house was designed for 2 systems, and there was no good way to run a main duct line from the basement to the attic in this house. One system would have been less expensive to install and there would only be one system to maintain instead of two. For these reasons, one system would have been my first choice.

Of course, we do have the ability to independently run each system (which is nice), but I wouldn't pay a premium for this benefit if a single system could have been installed and worked well. Working well is the key - this is why I stressed references. With as many installs as company #3 has, they may be able to give you references for installs that were similar to yours (old house, single system, etc.)

Like Joe just said, sometimes you can't get around two systems.

Get details of loop design in proposal. Share those numbers here. Also zoning and controls seem important for your project. Long term performance and satisfaction with the system will be influenced be the details of these.

50 gallon water heater for preheat tank

This shouldn't be replacing your current hot water tank, it only serves as a preheat tank to capture the (inexpensive) geo heat. Preheated water then goes into your current hot water tank which has to work less to meet your hot water needs. They aren't designed to be the only hot water source, particularly when you have some greater demand like family members.

I forgot to mention the other reason two units were recommended--if,
say, the upstairs unit breaks down, we would still have heat/cooling

Extremely weak story. Sounds like lack of competence, at best,
or at worst, a flim-flam. In all three bids, the aux heat strips
have more heating capacity than the heat pump(s) themselves,
so, even with one unit you're covered "in case of a breakdown."

Also a good idea to check out the installers on the IGSHPA
web site. While IGSHPA certification/training isn't a guarantee
of competence, it does indicate that the contractor is serious
about geo.

http://www.igshpa.okstate.edu/directory/directory.asp

None of these companies are on that website--it was hard enough to find these three to come out to where I live, even companies 30-40 miles away have such limited service areas that we are too far for them.

Our current water tank is hooked up to the oil furnace, and we have no electric water heater. Can the existing tank be reused for geo, or do I have to have the 50 gallon pre heat PLUS a new electric water heater as well? I think only #1 included this (the 80 gallon water heater)--the other two proposals just have the 50 gallon pre heat tank.

FWIW: It's my understanding that Water Furnace requires its dealers to go through training on their systems. No guarantee... as Looby stated.

A pre-heat tank can be an un-powered (or powered temporarily if you need extra capacity - ex. when you have guests in shoulder months) electric water heater. The finishing tank (a water heater) can be whatever you want (but you want to ditch the oil, right?) With your high hot water use, I would suggest you get a preheat tank and a buffer tank.

They are not necessary, but Marathon tanks are nice. Expensive, but low heat loss and a lifetime tank warranty. If we ever add a buffer tank (not sure that we will) to our current Marathon, it will be another Marathon.

Our current water tank is hooked up to the oil furnace, and we have no electric water heater.

If your oil furnace is going away, then it sounds like you will lose your hot water heater, too. You really should ask company #3 if they knew that. You don't have to have more than the single tank quoted with the system, but you will want it at least as big as the volume of your current water heater (assuming you have no issues with the amount of hot water you get) Typically, 50 gal would be a bit small for a family of five out in the country.

With just the one tank, you will lose quite a bit of the efficiency in using "excess" heat to pre-heat the hot water, but it will be less upfront cost. The system that takes maximum advantage of your heat pump's efficiency will use two tanks.

One unit, if there is room for required ductwork to make it work will be cheaper and work just fine.

I laughed out loud at the idea that a single unit would be "stressed" by running all the time. These systems are designed for continuous operation. It is perfectly OK for one to run all night during a cold snap or all day during a heat wave.

Tanks are cheap. I recommend sizing the preheat tank for as close to a full day's hot water use as is feasible. DOE figures 16 gallons per person per day, but I need to take my preteen stepson and his 25 minute showers in to see the DOE folks.

DO NOT buy the DSH option without giving it its own, unenergized or fired buffer or preheat tank to work with. It'll never pay for itself otherwise.

Marathons are primo - I went with 12 year GE 80 gallon water heaters because the local HoDepot was discontinuing them and I got the pair for a good price. To be honest, the incremental performance vs cost of the Marathons would never pay for itself, but I wish i had them anyway.

I agree with most of the others recommending #3 with one caveat; flex duct is an acceptable alternative to steel duct as long as it is properly DESIGNED and INSTALLED. Due to flex's spiral helical core, if the duct is not designed and installed properly, airflow will be compromised and the unit will not have the advertised performance. Here's a short example of how critical proper airflow is for the proper operation of an HVAC system. There can be a lot more variables but this basic equation is a simplistic example. The sensible (the temperature we can feel) formula is as follows: cfm x The system temperature change (Delta T) x 1.08 = Sensible Btu Plug in a couple of numbers per system DESIGN: 1600 cfm x 20F x 1.08 = 34,560 sBtu This number is what the system designer had in mind for this particular system. Now lets assume that due to poor installation practices, the system will only produce 1210 cfm of airflow and the temperature difference is now only 15F. 1210 cfm x 15F x 1.08 = 19,602 sBtu Simple math will now let you know at a glance that the system is only producing 57% of it's design which is why air flow is so critical with a system that depends upon proper airflow to achieve high COP.

I guess I am surprised, 35 btu sq ft for somewhere pretty cold sounds low for a building with that little insulation.

15 btu with insulation sounds like a lot of work, windows, doors as well as walls and roof?