I have a 32 x 16 AG pool and live in western PA. When we installed it the surrounding trees were much smaller than they are now. Hence, the sun no longer shines on the pool for as many hours a day to warm the water. It hovers in the 70s unless I turn the heater on which is a bit chilly for me even on hot days.

We contemplated trying solar but the only location we could use is too far away from the pool's equipment and access "eyes" and there would be a whole lot of exposed, ugly piping to get there.

We have a gas heater but at $400+ a month to maintain 82 degrees I could join the local Y and swim in their over chlorinated pool all year but would rather not.

We have an Aqua Shield safety cover on it which precludes the convenient use of bubble wrap if I turn the heater on to get it up to comfortable water temp. Can't use a roller because of the shield and there's not enough deck room to just ball it up in between uses. (I lift the panels & prop them up to use the pool if I have company. Otherwise I just open the end panels so I can get in & out, and clean the filter.)

Our pool is totally surrounded by a deck. We can crawl entirely around the pool under it. We were wondering if an application of that foamy insulation onto the outer pool wall would work to keep the water temp warmer for longer periods?

Has anyone tried something like this? OR - does someone have some other solution that might work?

All suggestions welcomed.