Quote Originally Posted by CarlD View Post
I'm not sure where Spensar is getting his information. The insulating part is correct, but the heating part is not.
Anyone I know in my neck of the woods that has a cover doesn't get much benefit from an increase in pool temperature. I am in Ontario and not in a real temperate area like you have in a lot of the US, so that is a caveat.

I cover my pool daily and tried not running the heater to see what the cover does alone. It didn't do much for raising the temp - you may get a couple of degrees, and it is at the top as you indicated. But the thermocline is thin and in our 16x32 inground pool the net effect isn't much. Perhaps if you are looking to bring water at a not bad temperature up a bit to a more comfortable zone, the cover will have some effect. No way in our area does sloar cover bring what was colder water up 5 degrees or so. That is heat increases attributable to the incremental benefit of a cover since even without a cover the water temperature will increase in hot sunny weather.

Anyway, that's IMHO and experience for conditions around Ottawa.

I just didn't want someone buying a cover and thinking it will give them a heat boost and be dissapointed. That has happened to a number of pool owners I've spoken to around here. Often summer night temperatures are a lower temperature than pool water and the cover helps to preserve the heat, even without a heater. I would recommend a cover for that reason and take whatever heating as a bonus.

I'll defer to the pros for other locations and my original statement may have been to broad.