Well, one of my potential installers just self selected himself out of consideration. He emailed to tell me he was about to send over a proposal - but he hasn't measured my house. :roll: I do have what sounds like an interesting proposal from someone else who did measure my two story house very carefully. When the addition is finished the house will be 4,200 sq ft . The proposal's for a six ton WF Envision, a desuperheater and a buffer tank, a 20K electric back up strip and 1040' of vertical closed loops. It is to have three zones, an Intellizone damper panel, three thermostats, an aprilaire 600 humidifier, a merve11 air cleaner and a UV-Aire Ultra Violet Germicidal light, if I want it at an extra cost. (Should I want it?) It says the six ton unit is rated at 74,400Bthu cooling and 55,5000Bthu heating. It is planned for a range of temps from 7º to 92º. However, the proposal also tells me that my cooling needs are 3.35 tons on the first floor and 2.87 on the second, which is a total of 6.22 tons. My heating needs would be 53,682 on the first floor and 43,879 Bthu on the second which is a total of 95,761Bthu. I have read that it is better to go a bit smaller with a geo system than larger, so perhaps the cooling is alright. But, what about the heating? I will be talking to the installer tomorrow. I would appreciate any input and advice. I am wondering if the loops ought to be longer as when he had given me a proposal before I planned the addition, it was for 1,200' of loops for a 2400 Sq ft house. With a bigger house it is now only 1040'. I don't want to be short looped. I do plan to ask him about it. Maybe, someone just transposed the numbers and meant to type 1400. Ground water temperature here is a steady 55º with a one foot a day ground water flow. The loops will be sunk in moist sand and gravel. I like this installer better than any I have spoken to, he is very experienced and seems to be honorable. All his references check out.