So I took the plunge and signed a contract for a 5 well ground source loop and the 3 ton and 2 ton heat zone pumps to work with it. The incentives amount to about 50% of what it will cost, which is pretty nice and we are estimating $1800/yr savings plus $300/yr in RECs. I'm struggling a bit with an option to do water heating with it as well. Adding a second water tank is necessary but takes up space, and benefit only accrues when the house is calling for heat or cooling; the water cannot apparently be warmed independently of that. Any insights you may have here would be much appreciated.
Excellent! My Waterfurnace closed loop well system is now about 14 years old. I think it's a fantastic unit, even with the early technology of 14 years ago. My preference in any heating system is 'forced air', to keep things moving, rather than radiant systems. I leave the fan on low 24/7 to keep the air fresh and maintain temperature uniformity throughout the house. No doubt this costs some electricity, but I do it anyway.
If you have several floors in the house (I have three, with the furnace at the bottom), make sure you have enough CFM ability in the blower to push the heavy cold air to the top floor. That has been my only nit to pick - the upstairs gets hot in the summer because I just can't push enough air up there.
I have the hot water pre-heat on my system, but with only the single electric water tank. Not enough space for the better configuration of a pre-heat tank, however, even a small one would probably provide more benefit than what I see. My understanding is that the water only gets whatever heat might be left over from the refrigeration cycle - my system at least.
If I was building it from scratch, I'd probably go with a small pre-heat tank if I had space. Otherwise... well... I'm not sure how much benefit you really get. If the plumbing isn't overly costly and the unit supports it anyway, I'd put it in.
I'd also consider a Heat Recovery Ventilator if I was able to fit it in. However, if you're retrofitting this might not be as practical.
FWIW, my average daily power consumption over a typical year is about 50 kWh per day. Seems like a lot, but the only natural gas used is for the stove and BBQ. Family of 5, 3300 sq. ft. of house in a climate that's cold in the winter and hot in the summer. And believe me, plenty of hot water goes down the drain...
