Goodmorning. I am contemplating having a geothermal heat pump added to my existing propane furnace, to be used for primary heating and cooling. Being new to geothermal, I am trying to resolve some issues. First, our home was built last year, 2x6 stick, blown insulation, 1700 sq ft, 10' ceilings throughout except they living room has 16' cathederal. Radient in-floor heat in the basemen, hot water is propane. We live in central Wisconsin and -20 F is common in winter. The contractor installs GeoComfort systems and recommended an open loop system, tappinig well water before it enters our filter system (high nitrates) and discharging via our sump pump discharge pipe. He quoted a 3 ton unit, which will provide primary heat and hot water, and cooling in the summer.

I have to admit this system sounds good, however, I am concerned about the discharge in winter. Our soil type does not drain well (loam soil) and I don't ice skate, so I don't need a skating rink. Also had concerns on the impact on the water table in the well. Our well is 167 ft, and the water column is excellent. I am assuming the impact would be no worse than a 4-5 zone sprinkler system running all spring, summer & fall. Closed loop is out of the question, we are perched on top of a glacial morane and it took 7 attempts just to sink a mailbox post.

Should I be concerned about the discharge issue? Also, does a 3 ton unit sound appropriate? Would appeciate any additional comments or feedback. Thanks in advance. 

I am also new to geo, over here in Green Bay, we had Alt Energy's do ours and we are happy with them. I am not real familiar with an open loop, ours is closed loop in a field. Our last house was on a 870 foot well with the water at 160 feet. If you run out of water you would have to sink a deeper well and that isn't cheap.

I think if you have a back up 3 tons should be fine for 1700 sq. feet but I think some will say that’s small. But if you made it through this last winter with your current system it will only get better with a 3-ton unit.

I would think 3 tons for your house would be sufficient. Just make sure they've done an accurate manual J 8th edition load calculation.