We have a small pool (7000-8000) gallons with a spa that spills over into the pool. Current setup is solar on the roof and a small gas heater for the spa which is broken and we'll be replacing this Fall.

We're going through the early stages of a roof claim with insurance and one of the comments someone made was that putting solar back on the new roof was a bad idea as it just invites issues down the road (drilling holes into a brand new roof).

As I mentioned we are replacing the heater this fall anyway - we're considering taking the solar out of the equation and getting a bigger heater so that we'll have the option to heat up the entire pool during the winter if we have family in town or the few times the kids want to swim when it's cold.

Anyone have any insight into this? I think my primary concern is lifespan of a heater, I'm beachside about 4 blocks from A1A in Satellite. For the limited times we'd use the heater for the entire pool I don't think I'm too worried about the increase in gas bill.

What about electric heater? probably better since you don't have to store gas. And use it only when you need it. Just flick a switch. I have an electric heater that broke a few years ago. Carpenter ants set up a next in the electronics and shorted it out. But, it was nice for that one week during christmas break with relatives in town to heat the pool.

Don't do gas- its insanely inefficient with a spillover and very expensive.

In the summer time, if you have a good exposure for solar, I would bet it could heat that hot tub up very well. The problem is the way a spillover setup works. If you isolate the spa, then the main pool is not getting filtered.

The best thing to do imo, is to get a pool company to get rid of the spillover, pipe it up so the spa and the pool are on seperate lines, so they can circulate seperately.. then get an electric heater for the spa.

My neighbor, an engineer, insisted on this setup and his spa is ALWAYS hot and he pays a fraction of what I pay in gas.

Thanks for the input. Fortunately ours is plumbed to be able to isolate the spa so we'd be able to do what you're describing and take the spillover out of the equation. A friend of mine has a pool cleaning business in Orlando and said the rule of thumb for electric vs gas is that if you want to keep the pool a consistent temp electric is more efficient but if you want to heat it up quickly every so often gas is the way to go. I am still doing research on which route to take if we do eliminate the solar system but had planned on gas just because we're on city gas for some of our appliances already. Just don't want to drop a bunch of extra money on a larger unit if it's going to go to crap in 5-7 years, not sure if they're similar to AC units beachside in that way.

It will die in 5-7 years. And probly have a maintenance call or two in between.

It heats the spa in 15-25 minutes, but thats still a wait. It takes a day or more + like 100 gallons of gas to heat the pool.

I'm sure you already know this, but you do have children, right, so I have to say it.

Solar is better for the future of the planet they will inherit.


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"The truth is incontrovertible.
malice may attack it,
ignorance may deride it,
but in the end,
there it is." -Sir Winston Churchill

A huge factor in keeping the pool at a constant temp is the use and efficiency of a pool cover in cooler weather. Get a really good one.

I went thru 2 electric heat pumps beachside in about 8 years, and barely used them. They were not as well rust-protected as a typical FL air conditioning unit.

Cost of electric got prohibitive for me during a cold winter.

iirc, heating rate for my 20,000-gallon pool was about 1 degree (F) per hour. In winter, if you want that 60-deg water closer to 80, you need to start a day in advance!

Edit: I haven't calculated the energy requirements, but it would be interesting to evaluate photovoltaic (electric) solar panels on the roof instead of the water-tubing panels.

Use the electricity to heat your pool whenever you want, which might only be 4 months out of the year. Use that electricity to replace FPL for the rest of it.

WG - it's a good point, and I've considered it but if I put solar back on top of the roof and it decreases the life of the roof by 5-7yrs it's a negative too, I'm sure roofing materials aren't great for the environment either.

Paddleout - that's an insane amount of gas, that definitely gives me pause.

Joe - thanks for the input, the photovoltaic is an interesting scenario...I had hoped our roof would last until Musk's new solar shingles were an option so we could at least consider those.

I had a solar pool heater on system added to my roof soon after I bought my house in 95. (shingle roof was a few years old)
I just replaced the roof last year and did not replace the panels, simply because it's so damn hot here now, I don't see the need. I spend more effort cooling my pool these days.

I don't think a properly installed solar panel system does much damage to roof life.

I'd like to see the math too, but am skeptical that a sun->electricity->heat system could be very cost effective Joe.

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"The truth is incontrovertible.
malice may attack it,
ignorance may deride it,
but in the end,
there it is." -Sir Winston Churchill

Not entirely out of the question, especially for the OP's small pool.

Solar radiation is approx 1400 Watts/m^2

at 25% conversion efficiency, 1 m^2 of PV cell could be 350 watts

a 5m x 20m PV array on a rooftop (16'x64') would be 100 m^2

That would output 35 KW or ~120K BTU/hr, which is in the recommended range for a pool that size.

The benefit is that you could use the PV electric output for your home most of the year, and devote it to the pool for the 3 coldest months.

You could also consider a hybrid "trickle heat" system where the PV electric helps keep it warmer than unheated water (cheaply) -- not at ideal swim comfort range, but warm enough that a short burst of gas heat is all that's needed when you're ready to swim.