When to start heating your pool

[Lenny]

Hi everyone. I'm in Northern Delaware (close to Philly) and this is my first spring with a pool. I have a heat pump and a hot tub (which I've used several times) but so far I haven't tried to heat the pool. I'm reluctant to start heating it until it's more likely to better hold the temperature. I don't mind spending some money to extend my pool season with the heater but I don't want to be foolish either.

I've already noticed the water seems to heat up faster than the average daily temperature due to the sun and maybe it's helped along by hot tub use (I mix in the hot water after. Hard to tell how much of an effect this has). The pool is 21,111 gallons including the 550 gallon hot tub. A few weeks ago my water was at 59 degrees and now it's in the mid to upper 60s. The weather is mostly in the low to mid 60s right now and over the next several days with a few days projected to be in the low to mid 70s.

Do you guys have a good rule of thumb to help you decide when it makes sense to start heating the pool?

Thanks,
Lenny

[kaybinster]

Its really up to you. I live in northern NJ and my IG pool is about 29,000 gallons. It was 45 degrees when I opened it at the beginning of the month. I turned the heatpump on last Thursday and was swimming in 72 degree water on Saturday. I will not heat it up to 78-80 until mid-May, but until then I will keep it between 70-72 degrees. Remember that the ground temperature is not going to change that much. As long as you keep the solar cover on when not in use you won't loose that much more now than in a month or so.

[Lenny]

Thanks, kaybinster. I don't have a solar cover and I don't think I'll go that route. I have a free form pool and I don't think I want to deal with it.

I've been planning to heat the pool for sure as soon as there's a week that's on the 70s and above and I might stick to that. If it were going to be warm this weekend I'd probably send it up a few degrees but unfortunately it looks like it's going to cool down by the weekend.

I'm already heating the pool one hot tub at a time

[kaybinster]

If you don't get a solar cover you are going to find your heating bills will be very high - even in the summer. The difference is huge, I went without the cover for one summer and will never do it again.

[Lenny]

Do you get full sun all day?

I was thinking that I would need the heater in the early going to get the water temp to catch up with the warm weather but that I wouldn't need it much again until the fall.

The perils of a new pool owner

[kaybinster]

You will need it at times all summer. An inground pool is different than an above ground pool. An above ground pool is surrounded by nice warm air in the summer on 5 sides and is only in contact with the ground on the bottom. An inground pool is in contact with cool soil on 5 sides and air on the surface only. Thus, even in the summer you will contantly loose heat to the ground, and if you don't cover it the cool night air will drain heat away as well.

There are many factors that go into the heat balance of the pool. Wind will cause a lot of evaporation which drains much heat, the cover helps prevent that. If you really don't want to use a cover there is a product called a fish or something like that which is some type of surfactant that claims to coat the water surface when the pool is not in use to minimize evaporative losses. I have no experience with it, but have heard it is better than nothing.