B.O.'s Federal incentives for alternative energy system look pretty good so far. For Geothermal off your federal taxes you can deduct 30% of your cost for the entire system, installation and any additional work required to install it.
Each state has their own incentives, some our pretty good, others are useless. You can look here for your states incentives:
http://www.dsireusa.org/
Cost of the Geothermal system was about 10% more than a new high efficiency boiler for our current hot water baseboard heat.
Cost of the Geothermal system was about 20% more than a new high efficiency gas forced air system.
That cost includes over 100 ft of trenching and line to dump the water return into the lake behind us. I did my own electrical work for the system which was $175 in supplies.
We went with an open loop system so we needed a new well with a larger pump. Our 1960's/1970's vintage 1/3hp pump with a 1-1/2" well pipe was not going to cut it. Plus it no longer meets new code for new well's. So we had a new 4" well with a constant pressure pump installed. New well was $3500 and was not included in the above cost. You don't need the constant pressure pump and you can go with a smaller pump, so our well options where $2400, $2800 or $3500. On the good side the constant pressure pump only needs a little 3 gallon pressure tank, so we no longer have the big 55 gallon one. Also we can adjust the pressure through the electronic control unit any place between 45 and 110 psi, default is 70 psi.
We are in the middle of an addition and remodeling and are adding 720sq ft to the house, so we needed a new furnace. We already had forced air for the AC, so we had the duct work and could go multiple ways.
We are not using the Geo system yet as there are clauses in the contracts that wallboard dust creates havoc and voids the warranty. So till the construction is done it's just sitting here.
Our electric company offers a $50 a month rebate for 5 months.
You can also have an open loop system that dumps into a dry well or even just out into a field. Our Geo system will use up to 4 gallon per minute for max heating or cooling. Should be good to zero degrees, if the temperature goes lower, it has electrical heat coils for auxiliary heat.
If you go with a closed loop system you need between 250-1000 ft of tubing per ton of heating/air conditioning. Depends if you go horizontal or vertical and the type of soil you have. Cost for us to put in 3000 feet of horizontal closed loop would have another $4K.
I looked at having solar panels for the hot water heat. But I really did not want the panels on the roof plus the one or two large hot water storage tanks in our tiny basement. It was very costly too.
