Just a quick report on a new system we had installed last Oct. It's a 3 ton Climatemaster Tranquility 27 with a horizontal ground loop, and desuperheater plumbed to an aux. tank that feeds our existing elect. water heater. It replaced a 20 yr. old forced air oil furnace in our 1400 sq ft older house (1840's vintage). Most years we heated with wood rather than oil (wood stove) and circumstances this year made it impossible for me to get my wood out of the woods (I usually went through about 6 full cords), and unlikely that I'd be doing much wood heating in the future. Rather than throw money away on oil to the tune of close to 3k per year, we decided to have a geo system installed, after taking advantage of a free energy audit, and doing some needed air sealing myself. So far the geo system is working better than expected. Having a constant temperature in the house is something that is totally foreign to us after many years with wood. Air quality in the house is so much better than ever, especially compared to the oil furnace which we had to use through the end of Oct. The geo system works as a whole house air filter compared to the old ducts and furnace which worked more like a whole house dust allergy creator. Humidity levels in the house are much improved as well. We did opt for a whole house humidifier added to the system, but didn't even need it til recently. The system kept us toasty in recent 0 degree weather, though I'd like to go through at least a week or 2 more of that cold stuff, just to prove to me that it's up to the job (after that, spring can come anytime). So, we haven't been through all of Jan and Feb yet, but so far, Nov, cost me about $35 worth of electricity for heating and Dec. around $65 ($ .11 / kwh current rate around here including delivery and taxes). This is with geo only...no wood burned. It has been warmer than usual here this year but electrical use has been less than I would have expected considering this. So, yea, it cost a bit up front, but looks like it will easily pay it's cost off over oil in the 7 years we estimated the payback to be.