Solar pool heaters: what you need to know

While pool owners are fortunate to have a place to cool down during hot, sticky weather, it’s not without its pain points; in an effort to keep pools comfortable and open for as long as possible, pool owners may spend a good amount of money towards heating the water to swimmable temperatures. If you have a pool and pay a lot to keep it warm, you should consider renewable energy options for heating. While you can rely on warm weather to passively heat your pool, solar pool heaters are a good option to consider if you want to save money while extending pool season.

What are solar pool heaters? How do they work?

Solar pool heaters use thermal energy from the sun to warm your pool water. Similar to solar photovoltaic (PV) panels, solar energy collectors are typically mounted on your roof. Water from your pool is pumped through a filter and up to the solar collectors on your roof to the collectors. These solar collectors look similar to PV panels but include tubes throughout the inside so that pool water can circulate in the collector and absorb heat.

Many solar pool heaters also include flow control valves and automated sensors. These components will detect the temperature of the water coming from the solar collectors compared to the desired temperature. If the pool water is cool and it’s sunny out, the flow control valve diverts water through the solar collectors to be heated and enter your pool. Alternatively, if your pool is too hot, the control valves ensure that additional hot water doesn’t enter your pool.

Heating a pool with solar energy is eco-friendly and helps save you money because you’ll be relying on free energy from the sun instead of purchasing the fuel you would otherwise use to heat your pool. The amount you’ll save transitioning to a solar pool heater will depend on the existing source of heat for your pool, the efficiency of your system, the upfront cost, and more.

Solar pool heater installation and operating costs

According to the Department of Energy, solar pool heaters typically cost between $3,000 to $4,000 install on your roof. Your payback period for this investment depends on how much you would otherwise spend on fuel to heat your pool and how expensive this energy resource is in your area. Most homeowners investing in solar pool heaters will break even on their investment in less than seven years.

The upfront investment of the system is the largest cost associated with this technology – operating and maintenance costs are relatively low. Properly installed, high-quality solar pool heaters should operate efficiently for 10 to 20 years.

How many solar collectors do you need to heat your pool?

The size of your solar pool heater will depend on a number of factors, including the size of your swimming pool, the desired temperature for your pool, and how much sunshine the collectors will receive (dependent on your geography, tilt of the collectors, possible shading factors, etc.) You can install as many solar collectors on your roof as can fit, but if your roof is covered in shade for most of the day, the solar collectors won’t meet your pool heating needs.

As a general rule of thumb, the surface areas of your solar collector(s) should be 50 to 100 percent of the surface area of your pool. This means that if you have a 10 by 20 feet pool (200 square feet total surface area), your solar collector surface area should be between 100 and 200 square feet. If you live in a climate where you’re using your pool for the majority of the year, you may consider sizing the system on the higher percentage end versus if you live in an area where you only swim in the pool for a few summer months.

Any qualified contractor offering solar pool heaters will be able to properly size your system given the specifics of your pool and the location of the collector system. If you live in a climate with a lot of cloudy days or experience some shading on your roof where the solar collectors might go, your contractor may suggest keeping an electric backup system.

Buying a solar pool heater: what are your options?

Most “solar pool heaters” you’ll find online are actually just the panels, which can be hooked up to most standard pool pumps. If you plan on installing your solar collectors on your roof, it’s definitely a good idea to consult a solar installation company or roofing professional to get the job done correctly and safely.

What solar pool heating products are available? There are many companies that sell solar pool heaters, so we’ve compiled a list of some of the popular options online in the below table for comparison:

Best solar pool heaters for sale

Other types of solar gadgets for your pool

You don’t have to install an entire solar pool heater to benefit from solar power. Here are some other solar-powered gadgets that you can use come pool time:

Solar pool pumps

You can use solar energy to power the motor in your pool’s pump, which is the component responsible for pushing water through a filter and returning it to the pool. There are a number of ways you can do this including powering your existing electric pump with a solar PV system, purchasing and installing a DIY solar pool pump kit, or using a stand-alone solar pool pump that floats directly in your pool and requires no installation.

Solar pool covers

If you’re looking for a lower-cost solution to heat your pool, one purchase you may want to make is a solar pool cover. Solar pool covers are more translucent than standard pool covers which enables sunshine to warm up your pool while keeping the water clean from debris. Covering your pool, with a solar cover or traditional one, will also help trap the heat and prevent evaporation.

Solar Sun Rings

Similar to solar pool covers, Solar Sun Rings float on the surface of your pool and absorb solar energy to heat the water below. These rings are also useful to prevent evaporation. One of the biggest differences between Solar Sun Rings and pool covers is the shape; Solar Sun Rings are smaller and circular, and you’ll likely want multiple of them to cover the surface of your pool. Because they are smaller, they’re easier to remove and can be better suited for uniquely-shaped pools that may not have a perfect shape for a more standard solar pool cover.

Floating solar lights

If you’re looking to light up your pool at night, consider solar floating lights as a solution. Many companies produce colored lights that will absorb solar energy during the day as they float on the surface of the pool and then use that energy come night time to provide lighting.

Installing solar PV with solar pool heaters

If you have a sunny roof and are looking to save the maximum amount of money on your utility bills, consider pairing a solar pool heater with a solar PV system. This is a feasible option for property owners who have a sufficient amount of roof space to fit both solar PV panels and solar thermal collectors on their roof. Alternatively, if you have a limited amount of roof space, you can install a solar PV system to cover the electricity needs of your electric pool heater and other home appliances with solar power.

By signing up on on the EnergySage Solar Marketplace, you can receive multiple quotes from pre-screened installers to compare costs and savings estimates for installing a solar PV system. If you’re interested in also exploring your solar pool heating options, simply note it in your account – many PV installers also install solar pool heaters (or can recommend a reputable company to do so).