How Solar Pool Heating Works in Florida

The short version

A solar pool heater uses the pump you already have to push pool water up to collector panels on your roof. The sun warms the water as it moves through the panels, and the warmer water flows back down into the pool. Do that for a few hours every sunny day and the pool holds more heat than it would on its own.

There is no burner and no compressor. The main thing using electricity is your pool pump, which runs anyway to filter the water. That is a big part of why solar is such a popular way to heat a pool in Florida.

The parts of a solar pool heating system

Collectors. The dark panels on the roof. Most pool collectors are unglazed, meaning there is no glass cover, just durable dark plastic with many small tubes for water to flow through.
Headers. Larger pipes along the top and bottom of the panels that feed water in and collect it back out.
Supply and return lines. The plumbing that runs from the pool equipment up to the roof and back down.
Solar valve and actuator. A valve at the pool equipment that sends water up to the roof or lets it bypass the panels. On many systems a small motor, the actuator, turns it automatically.
Controller and sensors. A controller compares the temperature at the roof with the pool water and switches the valve so water only goes up when the roof can add heat.
Pump and filter. Your existing pool pump does the moving, and the filter keeps debris out of the panels.

Already have panels that stopped working?

Understanding the system is step one. Getting it running is step two. AllSolar Energy repairs solar pool heating from any brand and any installer, including systems whose installer is out of business, and we have served more than 18,000 customers across 17 Florida counties since 1999.

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How it behaves through the Florida year

Solar pool heating does its best work on sunny days, and Florida has a lot of them. In the warm months many pools do not need heat at all, and a controller will simply keep water off the roof when it would not help. As days get shorter and nights get cooler, the system earns its keep by stretching the swim season on both ends.

On cloudy days it adds less heat, and at night it does not add any, so the pool slowly cools. That is normal. A pool cover makes a real difference here. Research from the Florida Solar Energy Center found that using a cover retains more than two thirds of the heat needed to keep a pool at a comfortable swimming temperature.

How big a system needs to be

Pool solar is sized by the surface area of the pool, not how deep it is. The more panel area you have compared to the pool surface, the more heat the system can collect. Roof direction, shade and how warm you want the water all play a part. The Florida Solar Energy Center publishes sizing guidance for pool collectors if you want to read the engineering side. For what a new system costs to put in, see our post on how much it costs to install a solar pool heater.

What usually goes wrong

The simplicity is a strength, but the parts do wear. Pool collectors spend years heating in the sun and cooling at night while carrying chlorinated water, and plastic eventually gets tired. The problems we see most are leaks at the panels and header joints, stuck valves, controllers or sensors that read the wrong temperature, and weak flow from a tired pump or a dirty filter.

None of that means the system is finished. Most of it is ordinary repair work. The bigger risk is a system that gets shut off after a small problem and never turned back on, often because the original installer is gone. That is the work AllSolar Energy does most: repairing and taking over pool systems other companies left behind.

Common questions

How does a solar pool heater work?

Your pool pump pushes water up to collector panels on the roof. The sun warms the water as it passes through the panels, and it flows back into the pool. A controller and valve decide when water goes to the roof and when it bypasses the panels.

Does solar pool heating work in Florida winters?

It helps a lot on sunny days, and many Florida homeowners use it to extend their swim season into the cooler months. It adds less heat on cloudy days and none at night, so the water will be cooler after a cold, gray stretch. A pool cover helps hold the heat you collect.

Do I need a separate pump for solar pool heating?

Most systems use your existing pool pump. Whether your current pump is a good match depends on the size of the system and how high the panels are, which we check when we look at it.

Does solar pool heating work on cloudy days?

It still collects some heat, but much less than on a sunny day. The controller may keep water off the roof when the panels would not add heat.

How long does it take a solar heater to warm a pool?

It depends on the pool size, the amount of panel area, the weather and whether you use a cover. Solar tends to warm a pool gradually over several sunny days rather than quickly.

What goes wrong with solar pool heaters?

Leaks at the panels or header joints, stuck valves, controllers or sensors reading the wrong temperature, and weak flow from the pump or filter are the most common problems we repair.

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