ITD your calculations are a little off, electric baseboard heat produces 3,413 btu per kilowatt hour of electricity. This is the baseline of how efficiency on a Geothermal system is measured, electric heat is considered to be 100% efficient, because no heat escapes outside the home. Since Geothermal uses only electricity, its efficiency as based on this. The average quality Geothermal system is a minimum 350% efficient, and this is being very conservative, the units I work with are 400% or better. at 350% the average Geothermal system will produce roughly 12,000 btu per kilowatt. Divide your 100,000,000 btu season by this, and you get 8,333 kwh. The average rate per KWH in NH is $.12 so your rough annual cost would be about $1000 so your are close enough on this number, but keep in mind this is the efficiency of a forced hot water system, not forced hot air, air systems run higher efficiency and also give you the benefit of cooling. Where your payback is a little skewed, is you didn't factor in the state and federal incentives. If you have PSNH you can get $4500-$7500 back once the system is up and running, if you have NH Co-Op you get $800 back per ton (average house is a 4 ton system) and you get a 30% tax credit, not deduction, that you can take over 2 years. The incentives pay for roughly half of the system, the average retrofit is about $25,000-$30,000 so we will use the high number, after incentives we are left with $15,000 and with a savings of roughly $2500-$3500 per year on average, that's a 4-6 year payback period, better than any other form of alternative energy.
Yes, obviously you have to spend a little more up front, and it takes up to the first 2 years to get the incentives back, but there are options that can also help with that. There is a loan called "Energy Efficient Mortgage" that will allow you to refinance your home, giving you a lower than normal interest rate to keep your payment roughly the same as it is now, but allowing you to get the alternative energy. This is a program set up by the FHA to make alternative energy affordable to anyone that owns a home, and the overall reduction in the interest rate will more than pay for the entire system.
More on this can be found here:
http://www.dsireusa.org/incentives/i...S36F&re=1&ee=1
You will also find the info on the local and state incentives on this site.
Chris Milner, Owner
Milhouse Enterprises
603-300-2943
Serving NH since 1992 with Geothermal, Solar and Wind solutions.