Pros: Very low heating and cooling costs
Cons: High cost of installation
I purchased a ClimateMaster TT-038 in late 2008 which I installed myself and had it up a running in early 2009. ( I don't recommend this as a do it yourself project unless you have a pretty good mechanical back ground). I purchased the unit new online for $4500 plus $300+ S&H. By buying it this way I didn't get the manufactures warranty, which isn't smart! My unit is a closed loop system that recirculates water (25% antifreeze and 75% water) through 1500 ft. of 1 1/4 inch 160 psi rated hard polyethylene pipe. I heat fused the (3 rolls of 500 ft.) together and buried it from 5-6 feet deep. I didn't have the electric heat package installed as I have base board heaters as backup if needed. As a equal payment costumer with my electricity provider, my power consumtion has dropped by $82 a month. To date the only problem that I have had has been a run capacitor on the compressor which I installed myself. While the initial investment is much higher, the water loop part of the system (whether open or closed) should never have to be replaced, making the cost of a new heat pump, once its useful life is up, in line with a covientional unit. Plus, the Feds and several states offer tax credits that will help pay a large part of the cost. I would highly recommend this unit to anyone interested in a geothermal heat pump.
P.S. My cost for the complete installation was about $12,700 plus or minus a few dollars. With the tax credit from the IRS and N. Carolina I have about $9,000 invested.