I have a pool in the back yard, and it has little shade. So at this
time of year it gets too warm - 90 degrees or more. I would like to
find a way to cool it down four or five degrees. There's a chiller,
of course, but that's too expensive.
I've tried to figure out a way to shade it, but haven't come up with
anything that wouldn't just blow away the first time the wind blows.
But I was at Home Despot the other day, and they sell 4x8 sheets of
some kind of foam insulation which has foil on one side. And it
occurred to me that just floating a half dozen sheets of that
on the surface, foil side up, might do some good.
There would be opposing tendencies with this. By preventing some of
the direct sunlight from reaching the water, the insulation would
reduce the heating rate, but it would also tend to insulate the
pool, thereby preventing the water from cooling by radiation and
So, to get the maximum benefit, I would need to put the insulation
on the pool only when it's in direct sun, and take it off at night.
And of course I would remove the panels when someone wants to swim.
By a good margin, it's the sunlight that heats the water, not the
air temperature. The pool has a surface area of about 550 sq ft,
and six panels would be 192 sq ft, or 35%.
Does anyone have an educated guess, or even a gut feel, whether this
might work or not? Or does anyone have any other ideas?