How long to heat pool?

[PoolDoc]

Pool temperature rise = mass of water x (heat added by solar heater + heat added by sun on water - heat lost by evaporation - heat lost to conduction (dirt) - radiative heat loss at night) . The ONLY one of those 5 factors that can be easily determined is the mass of water in your pool (~94,000 lbs or ~43,000 kg).

That's a long-winded way of saying, I don't know the answer to your question, and can't calculate it -- even if you gave me all the relevant weather data, your latitude; the surface area of the solar collector; the circulation set up on your heater; your ground temperature, and more.

The BEST way to answer the question is to try it and see . . . if you keep some records, after a couple of years, you should be able to predict heat rise your self.

[Spensar]

The biggest step you can take is getting a cover for your pool. It will speed up the process considerably.

Taking a look at a weather map for Australia, it shows about a 10 degree celcius difference between daytime highs and night time lows. Without a cover, you are losing most, if not all, of your heat gain during the day. That will apply when your solar heater is active as well.

You have a good sized 32'x9' pool, and without a solar cover, when the air temperature is lower than the water temp it is a 288 sq. ft. evaporation pan. Wind will also accelerate the heat loss. Kinda like trying to heat a house without insulation, or even a roof.

Good link here on pool covers. http://energy.gov/energysaver/articl...ng-pool-covers

[PoolDoc]

Thanks, Spensar

[CarlD]

OK, I'm gonna shoot from the hip here: If your solar heater's surface area is at least 1/3 to 1/2 your pool's surface area (or equiv), you can count on a few days to get the water warm, anywhere from 3 to 7 days I'd guess.