But the payback time would easily exceed the life of the equipment.
Here electricity is 6 cents per KWH, Natural gas is 51 cents per therm. Even when compared to a basic 80% furnace, geo doesn't make sense.
2500 square foot farm house located in Allegany, NY, built in 1860 with all new energy star windows and doors. About 60% of the house has been gutted, sealed and insulated with either R15 or R21. The house is plank so I have to stud up the walls with 2x4's or 2x6's to install insulation. The attic has about R90 and the rim joists in the basement are filled with R21.
I had a few people quote my house for a geothermal install. One guy came out in 2011 and he suggested I get a 5 ton system and he did no measurements. He took my spreadsheet for my fuel/propane and electric usage and calculated the size of the unit. About that time I started reading on this site on a regular basis. I also studied some of the WEL servers online and from that I was able to make a bunch of decisions as well. Last year when I called to get a fill up of fuel oil they quoted me over $1,000 for 250 gallons. At that point I decided it was time to make the leap. I contacted a local installer from Salamanca, NY (Jim Snyder, Domestic Energy Services) he worked with me and the trench installer. He had an energy audit performed on my home. He did a few minor changes and selected a 4 ton unit with all new duct work. I liked that he didn't give me any of the BS that the others installers did and he is 20 minutes away, and he actually used to build heat pumps and air conditioners for a very large manufacturer.
They put in a vertical loop of 2250 feet an average of 9 feet deep. They commissioned the system on 2/17/2012 so I have had it for just over a year and the savings is crazy. I have lived in this home for exactly 6 years. For comparison I averaged the total utility bills, electric, fuel oil, propane and pellets for the first 5 years. Then I compared that to the total utility bills for the last 12 months. The average for the first 5 years was about $5100 per year, the total utility bills for the last 12 months is $2500 of that about $800 is for heating. (And that includes the pellets for the stove in my man cave).
So that is my story in a nutshell, this system works really well the installer comes once a year to inspect the unit and replace the air filter. The temp is set at 70 or 71 and the system just runs. The installer was great to work with and I would suggest him to anyone who might be thinking about doing a geothermal heating system. The geothermal heating was the best investment I have ever made.