This conversation, just came up, with one of my chemical dealers, his house is newer. He says he is all electric, in his house and he is geothermal.

He dug the pit, himself,  roughly 50 x 110 ft, and 9 to 9.5 feet deep. Had either 4 - 700 ft loop or 4 - 1000 ft loops( he didn't quite remember). He thought they estimated at least a 4 ton unit. He has two water heaters and geothermal preheats, the water, too. 

He said his bills are 80 -135/140 dollar range, for electrical, monthly = he is super happy, but he said his house is really insulated good, too. He has had two circulation pumps failed, so far.

He did mention, they have a propane fireplace/stove, and it does kick out some heat, too. So, I sure there is a little benefit there, also. It's more for "looks" than heating.(He did mention ,that dang thing about burnt the house down ,too = he didn't go any deeper into that story)

I thought, when they drill vertical wells, after the tubes go down, then a special slurry gets poured down and helps provide closer to 100% contact with ground surface= instant efficiency.