A data point for your info. My situation is a little different from you, but I hope the info is useful. I'm ~75 miles south of you. I have a 20X36 IG pool, with 6 4X8 panels for a total of 192 sq-ft. I can usually easily stay at 88-90 degrees most of the pool season with a solar cover on at night. This year has been tougher than last year, but I have never dropped below 84 since we started swimming.