We're getting bids to replace our AC-only with a geo-thermal AC/Heat pump.
Kaching.
I'd be interested to know how the heat functions for you. We have a 1.5 ton heat pump system on our first floor (2 ton for the upstairs), and the 5kw heat strip in the 1.5 ton ahu is not enough to handle single degree temps like we had this past winter without the first floor temp falling 7-8 degrees. Need to rewire from the panel in order to handle a 10kw strip...but I plan to do that.
As far as costs...our winter electrical (all-electric 3 story house) was lowered well more than 50% just by installing modern vinyl windows. The 25 year old double hung wood windows leaked like a sieve. Our average monthly summer cost is less than $200.00 and winter is less than $300.00,,,and I like it cold in the summer, and warm in the winter.
Now, water bills...man...when I have the irrigation running - 4 days per week and 1 hour per day - it's in the neighborhood of $200.00 month itself. Truly crazy...