How's the pool build going? Did you decide on how you are going to heat it?
I will put in my 2 cents worth. I am in Pittsburgh, PA. We bought a house with a 20x40 in ground pool with no heater last summer (2020), and swam from July 4th until end of August. Due to a leak in the pool, near the end of August, I had to put in about 12 inches of fresh water, which significantly cooled the pool, to the point that no one but me wanted to swim in 74F water. At that point, we had a solar cover, but it was opaque, so it didn't heat the water too well.
This past spring, we redid the wooden deck by our pool. Since the plumbing was in the ground underneath it, we replumbed with new 2" pipe all around, new skimmer, and a 140K Raypak 8450E Heatpump. And yes, I ran a #6 AWG wire in a flex conduit for a new 60 amp pool sub panel. We did all the work ourselves, with some hired help for the decking and pouring some concrete pads for the HP and filter.. Oh, and we got a new blue clear 12 mil solar cover.
So, between the HP and the solar cover, the pool averages around 85F, and has gotten as high as 89F. Could've been higher if we desired, but IMHO, 89F is just not refreshing in hot temps. The pool had dipped down to around 79F after a couple days of rain 2 week from the Louisiana hurrican, which can definitely cool off the pool.
I don't run the HP very much actually (the HP says it's run 130 hours so far since early June, that about 1 1/2 hours per day average). Maybe 6 to 8 hours to warm up from cooler rainy days. On the warm days, maybe an hour or two if the water is under 85F, or if you want to simulate a jacuzzi by sitting near the return jet (the water is feels like a jacuzzi from that HP). I never run it at night, as you want to run when the temp is warmest, as you get max BTU's then. When it's 70's or higher, the pool heats up quite well, and having sun is a nice bonus.
I agree that the HP is more weather/temp dependent than a gas heater. In Pittsburgh, without a heater, you have basically a June to August pool season. With our new HP, we are still enjoying our pool. And if the temps stay in the 70's and 80's during the day, we will continue enjoying into the first week of October. At which time, we are getting our old concrete and the wooden walkways replaced with all new concrete, and finally get our pool pavilion built (been sitting in boxes since June).
Over the next year or two, my plan is to eventually run a new NG line from our house, and install a supplemental gas heater. Which will help with extending pool season further, and/or heating an eventual hot tub.
