4 ton geomax 2 with two 300 foot bores and double closed loop in each. Temps today all day were between 15F and 20F. Very cold for eastern PA. System has run all day in stage 1, adding stage 2 about half the time, and a couple hours of aux heat. (Ouch). But the house is warm. Estimated electricity cost at 15 cents/kwh is about $9 for the day.

You might want to check the PA Electric Regulator to see if you have options where your power comes from. I had been with WGES but their rate for 100% wind jumped up to 10.2. I went back to CleanCurrents and 100% Wind National REC is 9.3 (local wind is a little higher.) I only have a 3 ton but it stays in stage one (I'm south of Baltimore, 9 degrees this am, 20 all day) 4 tons of loop (4x200'). I'm also a firm believer of set-n-forget on the thermostat but I don't have any kids in the house either.

CEH

Your loop temps look good, DSH is making nice warm buffer tank, life is good!!
Chris

It's a shame that for part of the day you have excess capacity and for part of the day you are paying the high rate for aux heat.

Jonr makes a good point. A tight, high thermal mass house will shave the peaks arising from daily high and low temperatures. A looser lightweight (frame) house will act as Stu describes.