Summers in Massachusetts are easy in comparison to winters. Some people (myself included a bit) saw AC as the devil or something. I’m not sure why. When it’s 98F outside, and 78F inside (a typical setting), especially with 3x the insulation of a typical new house, it takes hardly any energy to cool the place. 20F temperature differential. And the house is well sealed, so there is not much chance for the basement to get damp, etc. No dehumidifier running 24/7 as in a typical new england house!
And compare this 20F temp difference in/out to a very cold winter day or night. Let’s say it’s 0F outside, 68 or 70F inside. That’s 70F difference, so obviously there is going to be a lot more energy needed to maintain that inside temp.
We had the AC on a bit yesterday (around 90F) and it was 24cents. 1.6KWh. That’s less than having the heat on for an hour when it’s 0F!
We should feel a lot more guilty about all the energy we all use to heat our house. AC is nothing in comparison!
We open windows at night as long as it cools off and is not 100% humidity. And then in the morning, close up and dry things off.
2 other things I wanted to say:
1. This house is more comfortable IAQ-wise (I find) than other air-conditioned houses I have lived in because the HRV means we are getting fresh air into the house 24/7 no matter the weather. Even if there is no temp difference, or wind, etc. driving air-exchange. Whereas with other houses, sometimes when they are closed up for a day with AC on they feel stuffy.
2. The PV (solar electric panels) are MUCH less efficient in the hot weather! In the cool but sunny spring days we would peak at 6KW (power, instanteous) 200W x 30 panels -vs- in the hot summer we peak at more like 5KW. But there are more days of sun and more daylight (around June 22) so we still generate a bit more in the summer months because of that.
It would occasionally go just BARELY over 6KW except that we have M190 Enphase microinverters which top out at 199W, so the very most we can make is 5970W and then the curve goes flat for a few minutes around solar noon before it goes down again.