Heating a pool in spring

[pb4uswim]

I posted in another thread about how to keep my water temp from dropping below a certain level, but then I wondered if that was even logical. I brought my temp up from opening temp of about 50 degrees to 80 degrees so we could swim on a few nice days. My thought was that now I should keep my pool from dropping to low (say not less than 70) just so I don't have to heat it up again. I wasn't thinking so much about the time involved as the cost to keep heating from a cold temp. That way for the spring when we only get a few days at a time of swimming weather, I could reheat for less money (and certainly less time).

Then I wondered, does it even matter? Would it be less expensive (use less gas) to keep it warm and bring it to swimming temp from a mid range temperature or would it be the same as letting it go down to whatever and just reheat the hole thing. I'm kind of thinking that it would be the same It seems like either way I'd be replacing the heat lost. So it would either be a few dollars every day or a bunch of dollars the day before we swim.

What are your thoughts. Any thermodynamic engineers here?

 

[crimson avenger]

I'm not a thermodynamic engineer... but you will definitely want to keep your pool >70 degrees to avoid corrosive condensation in your heater.

We have a small plunge pool, but keep the temperature at 88 degrees at all time. That way we can just jump in whenever we want - spontaneously.

 

[ajw22]

It is less expensive to let the pool water to fall to ambient temperature when not in use as long as you can wait for the time to heat when you want it.

Lets take the example of a pool maintained at 60 when ambient temperature is 55. You can spend a lot of BTUs maintaining it at 60. Or you can let it drop to 55 naturally and it will sit there at 55 costing you nothing. Then it takes one cycle of BTUs to bring the temperature back up when you need it.

 

[mknauss]

The most important thing is to cover the pool. That will retain a large portion of the heat, even if you just let it sit between times you heat it for use. As Allen says, it is best to just heat it up to desired temperature when you want to use it, but covering the pool will conserve quite a bit of that heat, even if it is several days to a week between uses.

 

[ajw22]

I'm not a thermodynamic engineer... but you will definitely want to keep your pool >70 degrees to avoid corrosive condensation in your heater.

Depends on the design of the heater…

The Pentair MasterTemp Heaters says:

• Operating this heater continuously at water temperatures below 68° F. (20° C) will cause harmful condensation and will damage the heater and void the warranty.
• When starting the heater for the swimming season with a water temperature below 50° F (10° C), the heater may be used to heat the water; however, make sure that the heater operates continuously until the water temperature reaches the heater’s minimum setting of 68° F (20° C).

The Hayward H-Series heaters say "Do not use the heater to maintain the water temperature just above freezing or for freeze protection."

Heater Condensation - Further Reading

www.troublefreepool.com