Solar Heater For Spas

Most people that have a spa in combination with a swimming pool have an electric or gas heater installed in Southwest Florida. However, some spas are installed without any heat source, and we get lots of questions about whether a spa can be heated with solar panels.

Solar Panel Heater for Spa
Spas are best heated with a solar panels if the spillover is turned off.

In a traditional pool/spa combination, water spills over from the elevated spa into the pool. Effectively, your pool and spa are a single body of water that continually circulates. This works by drawing water from your pool drains and returning it to your spa jets throughout the day. When you want to use your spa for therapy and enjoyment, valves are turned to draw water from the spa drain only, isolating the spa and stopping all circulation in the pool.

A solar pool heater will heat your spa and pool water simultaneously, but because there is such a large volume of water to heat, temperatures may not reach your desired spa temperature, and you probably don’t want your pool at spa-like temperatures anyway. If you want to heat you spa only, the solution is simple — isolate your spa and circulate only spa water through the solar panels. The temperature will rise much more quickly and will reach much higher ultimate temperatures. For most of the year you can heat your spa to typical temperatures of 100-104ºF.

There are some important caveats:

  • You need to plan ahead. Solar panels will heat spa water more slowly than an electric or gas heater. If you plan to use the spa at night, you should isolate it in the morning.
  • Pool water needs to be circulated. You can’t leave your spa isolated indefinitely.
  • When you are finished using the spa and set your valves back into spillover mode, your heated water will be distributed throughout the pool and spa (this applies to any heat source).
  • Solar energy is weather dependent and does not work at night (obviously).

If you do not have a heater at all, you can use your solar panels to heat your spa if you plan ahead and the weather allows it. No matter what, both your pool and spa will always be warmer than a pool without solar pool heat. If you have a traditional electric heat pump or gas heater, it will not have to work as hard, saving you money.

While a solar heater alone for a spa is not perfectly ideal, it will increase your enjoyment dramatically, and can save you money on your heating costs. Understanding how your pool system works and planning ahead is key to a satisfying experience.

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