We unfortunately did not choose it after careful consideration because we would have to dig vertically and it was much more expensive than we had first thought. We just couldn't fit it into our budget. So we settled for an energy efficient heat pump. But I love the idea of geothermal!

If you take just 1/3rd of the cost of geo and put it into your home's shell to increase the tightness and insulation levels, it will make a much cheaper air to air HP match the energy use of an expensive geo unit. A short (5 years is short) payoff for geo means your house is extremely inefficient. You are relying on a 300-400% efficient hvac system to make up for a leaky house. Spending only a few more thousand on the shell will give you energy useage numbers similar to the geo, but at a much lower up front cost and no hassle of messing with rebate, tax return, etc.

Lzerarc - I don't think our house (future house, whatever) is inefficient. The builder says that if we got a formal quote they would say 9 years but he thinks about 5 because the quotes assume you keep things 68 in the winter and 78 in the summer, which most people don't do.

Obviously, we're just at a prelim stage so still even deciding if it's a viable option worth looking into.

Everyone's situation will be different based on the size, construction and location of their home. I can tell you our experience. We are currently finishing a new build in central Iowa. We are in the country on ten acres and we get a great deal of wind and extreme weather conditions.

We chose air to air heat pumps, with back up propane furnaces. We have two units (a 3 ton for the living areas and a 2 ton for the bedrooms). Our home is 3700 square feet on the main and second floor, with an additional 2400 square feet in an unfinished basement. The house is constructed with double stud walls, for a total wall thickness of 9 1/2 inches. We then paid extra attention to air sealing and insulated the exterior walls with sprayed "spider" fiberglass.

The additional cost for the double stud construction was much less than we would have paid for upgrading from the air to air heat pump to a geothermal system, or for upgrading to spray foam insulation. We had an unusual situation where my husband's friend is a former HVAC contractor who assisted us with installing the system. We only had to pay the wholesale cost of the equipment and supplies. If we had done geothermal, we would have needed to hire a contractor to do everything, so the cost would have been substantially greater. I also have heard that the maintenance costs are normally higher over a ten year period on a geothermal system, than a more conventional one.

In the end, I am glad we spent the extra money on the shell, instead of the mechanicals. Our rural electric cooperative allowed us to install a second meter on the property and we are charged half price on all electricity for heating and cooling. Our bill last month for heating was $12. We keep the house at a very comfortable 70 degrees and while it was cool in Iowa last month, it didn't get below 15 degrees outside, at which point the back up propane furnaces kick on.

Again, everyone's individual building situations will be different. You need to evaluate if the extra money spent is better off used on the shell (windows, insulation, ect.) or on the mechanical systems. Good luck!

I'm certainly not an expert in this area, I only know our experience. Our Geothermal unit was expensive, not denying that. But so far we love it. We did go the extra mile for an energy efficient home. I remember the insulation guys telling us "Your builder goes above and beyond what other builders do!" We have a 2600' ranch with finished basement and infloor hydronic heating. We also have dual meters, and are on reduced rate. We are all electric except for our fireplace and the kitchen cooktop. Our electric bill that we just received was $150. I don't know what part of that is heating. We are in Wisconsin.

We have not moved in yet, but chose geothermal because it seems like the most reasonable and environmentally friendly way to heat/cool our house at minimum cost. We anticipate that future energy costs will most likely increase, maybe substantially, so this provides a hedge against that. Contrary to above, most of what we read from a variety of sources suggests the maintenance costs are less than conventional systems.

Obviously, if you have a BIL deal that lowers your traditional costs and can get half-priced electricity in perpetuity without the capital cost of geothermal, then that makes more financial sense.

Be sure to find a contractor who has experience in designing and installing geothermal and get several quotes.

Cotton-
If you have the info, post up the square footage, exterior shell design and r values, design temp values, cost of electric in your area, and climate zone (I am assuming 5) and I can give you a better idea.

spf5209: We also took into consideration the rising cost of energy, and I feel good about the environmental aspect as well.

Our last home was a 1916, 6500 sq ft Arts and Crafts home, and our utilities averaged $600/mo. So a $450 a month difference (yes a smaller home, 6500 sq ft versus 5200), our payback will be about 5 years compared to the other house. We can't know what our utility bill would be if we didn't have the geo, so the payback may be more or less. I'm not understanding the rationale that our house isn't energy efficient because we have geo. Educate me, please.

Geo is a win-win for us. Our backup furnace has not kicked in yet. We keep our daytime temp in the house about the same temp all year 'round...about 68. Cooler at night for sleeping.

Everyone has to make their own determination on this. Because geo works so well in our climate, and our lot was perfect for it (high ground water) it was a no-brainer.

I don't want to speak for lzerarc, but I believe the comment about a house not being energy efficient if the payback on the geothermal is a short time refers to the fact that if you have a very efficient shell, the need for any type of heating/cooling system you have to run at all is greatly reduced.

With our double stud walls, we have approximately R40 in the walls and we have another R60 in the attic. Because our heat loss is so low due to our shell tightness and insulation properties, our heat pumps do not have to run often to keep the temperature consistent. If we had put in a geothermal system versus our air to air hybrid system, the payback time would have been closer to 30 years because the difference in our bills would not have been that great due to the little amount of energy required to heat or cool our very efficient shell. We just are not using much energy to keep the house at a comfortable temperature, so having a system that uses less energy does not have a quick payback for us.

However, my parents live in a 100 year old farm house only several miles away from mine. When their furnace is ready to be replaced, they will definitely be looking at geothermal, because the payback time for them would be much shorter. They have a home that can never be insulated to the extent ours is and the difference in their monthly bills will be much more dramatic.

Often times, when dealing with new construction, the cost of increasing the insulation and energy efficiency of the shell/windows/doors is much less than upgrading the mechanicals. We would have spent approximately $15,000 to upgrade to geothermal. Our cost to upgrade to double stud construction with the additional insulation and air sealing was $4,000. Our builder/framer had not built a double stud house since the 1970s and told us he underbid that portion of the contract. We offered to pay him more, but he stated that he was not going to deviate from the price he originally gave us, so someone else's cost for the difference might be less.

Here is what the builder wrote in the specs about insulation. It is 2x6 construction and all brick exterior, ~3400 sq ft, full two story with basement. Windows are Windsor aluminum clad. There is an extra layer of foam he says he can wrap the house in for an extra $1k to make it R40 (I think?), which we would do regardless.

WALL - 6" BATTS (R21); CEILING - BATTS OR BLOWN FIBERGLASS (R30 / SLOPED R40 FLAT); GARAGE CEILING (R30)

We decided against it: We just heard that there could be "inconvenient" maintenance costs and that some people weren't sure if it was worth it years afterward. I guess more efficient homes and increased R values can help these days vs. 15 years ago...?

Also: We really didn't want to finance it on 30 years! Think of the extra interest paid and then weigh it vs. the monthly savings.

We went with geothermal because we had a 600+ foot dry well. Since the hole in the ground had to be paid for, we decided to put it to use.

You definitely want to opt for the extra foam outside your sheathing, although it would have to be very thick to bump you up to R40. Beware of claims that say 'equivalent to'. A 2X6 wall is nowhere near R21 NET value. Because of the studs conducting heat through the wall, it is actually much lower than the insulation rating. A sloppy installation of insulation lowers the net value also. Throw in the windows, which will never be anywhere near the insulation value of the walls, and it's easy to drop down to a net R of 10-12.

Current technology for frame construction includes external foam, impervious sheathing such as ZIP, carefully taped to prevent air intrusion, caulking between studs or 'flash and batt', where a thin layer of foam is applied to seal things up before batts or blown-in insulation, and a lot of attention to other leaks, such as electrical outlets and switches, ceiling fixtures, wiring, plumbing, and any other penetrations. They even make gasketed door hardware to prevent drafts. The house should then be blower door tested, where the air in the house is pressurized to measure the rate of air leakage. All of this costs money, but also increases the pay-back time on a geo system. You'll have to weigh the costs, and try to guesstimate whether it actually pays off in a reasonable time frame or not.

We choose geothermal for several reasons. Money saved is a big one. When we built we basically deoubled our square footage. Our energy bills are basically the same for the last six months as our old house. Our old house was a tract home, We did not just do geothermal. We had our envelope done properly. We used blown-in cellulose throughout. Low-e windows. The cost difference between a furnace and geothermal was the same as running a natural gas line to our house. Our payback time was zero due to that before tax rebate. Another consideration is the lack of an outside unit. At our old house the air conditioner was next to the porch. Any time it turned on you could not have a conversation. If I am not standing next to a vent or the unit, I do not know the geothermal is on. The unit is actually quieter than our furnace was. With the hot water superdeheater you get free hot water in the summer and cheap hot water in the winter. I was told by various people who have geothermal that their house felt warmer in the winter before we built. Now that we are having colder weather I agree with them. We set the house at 69 initially but it felt too warm so we turned it down to 68. We keep our house at 72 during the summer.

Cotton-
Flag and Westi are exactly right. Modifications to your shell will be much cheaper then going geo, and will have a faster payback since the upfront investment is much smaller. It also reduces your overall heating requirements for the life of your house no matter what type of heating system you go with. Say you go with both options (geo and shell)...you can increase your shell and that would also decrease your geo requirements. When you can change from say 4 tons to 2, that saves anywhere from $4000-8000 on wells and equipment depending on costs in your area.
Also, as Flag mentioned, r21 is by no means efficient, infact is barely (current code) minimum, and will not hit new 2012 energy code. Batt insulation is drafty, never installed correctly, and promotes air convection within your wall bays. I would at least recommend blown insulation in the walls. This will help some and come at a low upcharge.
Also, I am curious on this layer of foam that can boost from r20 to r40 for only $1k. To get r20 in foam, that is 4" of XPS foam which would cost several thousand upgrade just for material, require strapping and long screws to secure it to the house. Also, your climate zone is critical when dealing with exterior foam. You need to make sure you have enough r value on the exterior of your wall to prevent condensation within your wall at the sheathing plane. Thin foam can actually be more dangerous on your house than no foam at all. Assuming you are in zone 5, you would need 2" of foam to keep the dew point within the foam layer.
To be completely honest, your wall type was exactly what I was assuming, which would explain a faster payback....

I am working on a double stud wall project that is costing only about 1% more than a standard code min 2x6 house. However to heat the 3000 sqft, the load requirement is only 18,000 btu total in Zone 6. Most small 2 ton furnaces are even too much for this. THe construction type is very simple, easier then 2x6 with exterior foam in fact.
For this project we are using the Mitsubishi hyper heat mini split heat pumps, 1 on each floor. They cost about $2400 each, installed. $7000 is the total cost for the hvac system for the entire home, and that includes an HRV too.
Im not trying to talk you out of geo as it is a very good system, very efficient, and very quiet. It can also be used to help offset some of your hot water heating as well. All I am suggesting is put more money into your shell. Best case, you go both, geo and more in the shell, and your money out of pocket should be a wash since the money you spend on the shell can be saved on the geo wells/equipment since you will require a smaller system. And the result is even lower monthly bills.

Regarding the load requirements being lessened with the increase in wall R value, I can definitely agree with that. On our double stud build, we had a difficult time getting an accurate Manual J calculation done. We are oversized with our 3 and 2 ton units and are having to make some adjustments as a result. None of the HVAC contractors in our area had ever seen a wall assembly with as high of R values as we have and couldn't believe that our load requirements should have been substantially less.

We also went with the double stud construction because as lzerarc said, the construction type is very simple. Few contractors in our area have ever done either ICF or SIPs construction. With our double stud plan, we were able to go with a small builder who was willing and easily able to adapt to our unique requests. To build the highly insulated structure, the only change made to their normal techniques was basically framing the exterior walls twice and using much wider stock to box out the window and door openings.

For all you folks that had geo installed, can you post what you paid for it? What tonnage? State? What s/f?

We are in northern WI, and the home is approx 5200 sq ft finished. Our geothermal cost included 5 ton vertical loop system (five- 200 foot shafts), heat pump, back up furnace, programmable thermostats, radiant floor heating (I think 6 zones), humidifier, hot water heater, air filter, all ducting, labor etc, etc. Without looking at the bid, I can't remember all it included. It's been awhile, but if memory serves me correctly I think our net cost after ALL rebates was in the neighborhood of $22,000 -$25,000. I could be way off on these figures. Without looking at the bid, it's hard to remember everything. Our builder got 2 or 3 bids, and we did not choose the least expensive. In fact, we chose the most expensive because he was the most experienced.

No geo here. Estimated cost was $10k + over conventional net of rebates and estimated annual savings was $300.

Geo is ideal with no NG, cold climate and average or below average shell. As has been said, much cheaper just to improve shell in the North and really minimal savings in the South (and the envelope argument still applies). The problem in the South, is that the envelope improvements don't help the a/c load as much so you need a big system.

Rant on: When geo does make sense, it is usually because of rebates. Well rebates cost the government money. While obviously I would take one if it was coming to me, if I had the choice between spending $5k on envelope and $5k on geo that cost the government $10k for equal results - I'd go with the envelope. So if the payback numbers look close, go with the envelope and help the federal deficit...

But what hasn't been mentioned is that geo should last longer. It is also more complicated and more things to go wrong - but that should be cheaper than replacing the actual unit. As far as noise, usually the placement of the condensors makes that a non-issue.

I chose geothermal for a home in suburban Philadelphia. The cost of an 8 ton system next of tax credit was $22k. System is comprised of a 5 ton and 3 ton Tranquility 27 units. We have 4 300 foot bore loops.

The home has 6500 sq feet of conditioned space. Our electric bill is less than $300 a month average over the full year.

The home is less than two years old with a high quality building envelope.

I figure payback is less than 6 years after the tax credit.

Here's what our costs were. We are also near Philadelphia (a little over an hour outside Philly) and we have a little over 5000 square feet upstairs, plus 3200 square foot basement:
Geo thermal system, Climatemaster TTV 5 ton First floor, 2 Ton Second Floor , with Humidifier. 4 wells at 270
Geo Cost $30,500 includes drilling allowance for four wells
Radiant floor $13,400
Total Heat/ac $43,930

We have a gas backup system and radiant heat in some rooms w/ a separate boiler for the radiant heat.

The estimated savings was $1800 a year for us. I'm not sure what that is based on and I don't know what our bills will be because we aren't moved in yet. I do know we are on propane gas and I run the heat and A/C almost all the time pretty much (we keep it at 68 in winter and 70/71 in summer)

I am pretty astounded at your numbers, beagles. We called two people and have a slightly smaller house (smaller basement). One quote, from the experts who do it all the time all over north georgia, was 100,000. The other quote was more like 70k, from someone who really rarely put them in. 15 SEER heatpumps (4 of them) were 21,000. Given our mild climate, the payback was so long it didn't make financial sense. However, I would have loved to have gotten rid of those 4 a/c units outside!

To be clear, in case I was confusing, that is JUST the geothermal cost. We have a gas system as well which I believe cost another $29,000. But that was included in the price of our house so I don't know exactly what the cost of that was since it was just included (we paid cash for the geothermal separately and had a separate line item charge for the radiant heat). So, I don't know if we're comparing apples to apples here or not.

I believe the original plan was for us to have only 2 A/C units, not 4, which is odd to me now that you say you have 4 and your house is smaller. Do you have 4 zones (we have 2 or 3, I'm not sure if the basement is on a separate zone or not).

A Gas system costing $29k? That can't be right.

Geo cost is extremely regional. If you think of the actual mechanics, a geo system is just a well and a heat pump. The heat pump just uses water instead of air. So $100k is absolutely ridiculous but a good reputation without a lot of competition allows such things. But at the same time, a lot of people would love to pay only $21k for 4 HPs installed in new construction.

BTW - why 4 heat pumps? Especially if you don't like the look. We have 2 serving 5300 sqft. I don't know if they are in yet but just think of double the maintenance.

No idea david - that is just the way it worked out. The square footage I stated is wrong though. We have a large guest suite with bath and good sized closet in the basement which we are not completely finishing but we did heat and cool it (brought it to sheetrock). We probably have around 8000 square feet including that - maybe more. I don't really count it in square footage because it doesn't feel finished. We also have probably 350 feet of mechanical/storage down there. Upstairs is around 5500 square feet. Our basement is big (same size as the first floor) which is around 2800 square feet, so when you take out the mechanical we are close to 8000 square feet.

We have one for the upstairs, one for the master bedroom and part of the basement, one for the downstairs and one for the rest of the basement.

Can I ask a stupid question...I'm a bit ignorant on this. We don't have a separate A/C unit. We have hot humid summers here in the midwest, and the geo keeps our house comfortable at 68 during the day, and cooler at night. Why would you have a separate A/C? Or am I misunderstanding the terminology?

wow, some of these geo prices are insane. In our area a 5 or 6 ton system would run about $35,000-40,000 including duct work and ERV. My 2 ton system I got a price on for my 3200 sqft new house was $19,800 including wells, ductwork and ERV (this was for a high end Waterfurnace COP-5 with desuperheater too). All numbers before rebates/tax incentives.

I agree lzearc and have seen similar quotes if not a tad cheaper. I have seen less difference in price between tonnage than you as well. Going from 2-4 tons was closer to 2-3k which is mostly in the well pricing, the equipment tonnage difference was amazingly small. This was for the new Bosch line (formerly Florida Heat Pump)which Ferguson is selling now, it looks like amazing equipment and with Ferguson backing it, Iam really excited about using it.

My extra costs in more tonage was related to larger homes requiring more ductwork, tpyically zoning, etc which all play into the total amount.