Solar pool heaters are an easy, cost-effective way to bring solar heat into your swimming pool. When it’s sunny outside, there’s nothing better than taking advantage of pool season. But as the day goes on, the pool temperature drops, leaving you shivering. That’s because the sun is setting and there’s less solar energy reaching the pool water.

With a solar pool heater, you have more control over what your water temperature will be. Upon installing the solar heating system, a pool owner can optimize the sun’s heat by transferring it to the pool water. Most solar pool heating methods work for both an inground pool and an above-ground pool, so long as there is enough sunlight to reach the solar panel array. You control the temperature with the press of a button, and the solar pool heating system adjusts its output to match your preferences.

Whether you prefer the water warm or hot, solar pool heaters can accommodate what makes you comfortable. With solar power on your side, you have access to a renewable pool heating system that will keep you and your guests warm all day.

How does a pool solar heater work?

Solar pool heating works with a simple three-step process. This process solves the most basic question: How do you get solar energy from the sun’s rays into the pool water itself?

The first step is collection, and it’s where the sun comes in. The earth’s rotation allows the sun’s heat to distribute across the whole globe. The sun is a constant source of energy, heat, and light. But as the earth keeps turning, your angle relative to the sun results in less solar energy.

That’s where solar collectors help out. A solar collector optimizes how much energy the sun produces by absorbing its rays. The collector’s job is to make sure sunlight gets picked up by the water. But if you just angle a solar panel toward the water, there’s no guarantee that it will warm up the whole pool.

Therefore, each solar controller has a mechanism that channels water around it. The water is sucked through a short series of pipes leading to the solar panels. As it passes by the solar pool heating panel, the water picks up the heat the collectors were absorbing. So long as the solar thermal collectors are picking up sunlight, they’ll keep heating the water as evenly as possible.

One thing to keep in mind about this first step is that not all solar pool collectors are created equally. Glazed solar panels are much better at heating water than unglazed ones.

The second step is distribution. Once the water has been heated, it’s ready to go back into your pool. At this point, the water’s next stop depends on your pool heating system. While not essential, some solar heater setups feature a regular pool heater for the water to funnel through.

While a solar heater is usually more cost-effective than a gas heater or an electric pool heater, it may not be a bad idea to consider having a backup. A heat pump that uses another energy source is still effective, even if the resource it uses may be more expensive.

But regardless of what type of pool pump you use, it should integrate well with a solar pool heating system. It’s a matter of preference when it comes to the types of solar pool heaters you’d like for your pool. When planning your solar pool heater installation, be sure to also decide whether to include a gas or electric heater in your system.

After this optional stop, the water makes its way back into your pool. As the warmer water enters the pool (or hot tub), it distributes its warmth to the cooler water around it. When two bodies of water with different temperatures meet, they’ll balance each other out until they’ve reached a temperature between the two original levels.

It’s important to note that warm water rises to the top, so be sure to put the warm water’s exit valve at the bottom. That way, it can rise and heat all the other water as it leaves the heat exchanger. Like a solar greenhouse, pool heaters let the heat seep through and warm everything in the unit.

The third and final step is confirmation. The system asks, “Is the water warm enough yet? Should we pump more through the glazed solar panels, or is the water temperature at an optimum level?”

The system confirms the temperature by sucking out water through a motorized valve. The valve and connected pump lead the water through a filter. The filter’s job is important: it removes any impurities in the water before running it through sensitive electronics. Otherwise, the water could damage some of the internal systems connected to the glazed solar panels.

At this point, the check valve passes the water to the auto valve, then to the solar panels. There’s a temperature bar in these panels that checks the water and confirms its temperature. The system uses this reading as an estimate of what the total pool temperature is. If the water is below the solar controller’s temperature setting, the system will keep pumping water to the solar panels.

If it’s met the temperature requirement, the motorized valve will allow the water to stay as it is. It will maintain the desired temperature and, if set automatically, will keep diverting energy to compensate for heat loss throughout the day. Remember that the system’s speed will vary depending on your pool size. The bigger the pool, the harder it is to warm up or cool down.

How do you turn on a solar pool heater?

It’s pretty simple. You just turn the valve and open it, allowing the water to pass through. Once there, the motor will take care of the rest. The motor is the key to the whole system because it drives the water through the entire process.

Some solar collector units might be even simpler to activate. Lots of them are entirely electric and can be turned on at the press of a button. You can consider attaching them to a solar battery charger, which retains solar electricity until it’s needed.


How do you choose the best solar pool heater?

The answer varies based on several factors, but here are some general brands to consider. One of the best panels on the market is the Heliocol Swimming Pool Solar Panel. Its sleek design looks great, instead of the clunky aesthetic most solar panels have to offer. The Heliocol panel is well-designed and extremely efficient. It’s also fairly easy to install and optimize, meaning you won’t be spending the whole weekend putting them up.

Another model to consider is the Fafco Solar Pool Heating System. This unit is lovingly nicknamed the “Solar Bear” and comes equipped with a 20″ solar panel. It’s extremely durable and can stand up to the elements for years to come-in fact, each model has a 10-year warranty. While you may need to install more panels depending on pool size, the “Solar Bear” comes as a complete solar technology package. You don’t need connectors to have the unit work, and it comes with a large solar panel. Just be sure to give the unit some extra room. It may take some strategic placement to get the Solar Bear to start hunting for heat.

There’s also the GAME 4721 SolarPRO Curve Solar Pool Heater, which is an efficient curved panel. Its design allows for maximum capture while being gentler on the wallet. While the SolarPRO also enjoys an easy installation, keep its output in mind. It’s not as hefty as other solar panels, so you’ll either need several of them or a different model. But for what you’re paying for, the SolarPRO is a good option to keep in mind.

How do solar-powered pool heating systems get installed?

There are plenty of professional installers to help you along the way, but it’s not uncommon to find a pool owner who handles the installation all by themselves. As you may have noticed, each of the best solar products we discussed has one thing in common: ease of access. They’re easy to install and don’t require an engineering degree to operate. There are plenty of reliable products that are within your price range and technical expertise.

Ask an expert about the specifications for your pool before making any firm decisions. When it comes to setting up complex systems, such as the motorized valve, it’s important to get things right. Piping, motors, and electronics all involve sensitive machinery that can get broken if you set them up incorrectly. Because of the number of things that can go wrong, it’s recommended that you find some local experts in your area to help with solar pool heater installation. You might consider consulting local companies for help. If you’ve already got solar panels installed from one company you know and trust, ask them for help. They’ll probably have some pointers to give and a few experts to help out with the setup.

Of course, you don’t have to involve someone else in the project. Many people can work with the materials involved and not run into any problems. So if you feel confident doing it yourself, great. No problem. Experts will still be around to help if you need their advice and expertise.

There are also quite a few people who decide to take their installation even further. It is possible to create a DIY solar pool heater by collecting and assembling the materials all by yourself. 

You’ll need lots of raw materials on hand, of course. You could use a length of irrigation hose for the solar collector (and even spray-paint it black, which lets it absorb more heat). There are tons of options available for the valve and motor, so toy around with what you have. You should also consider whether to install a solar generator or not. If you do, the generator should be large enough to power the heater’s components, but probably not be installed on the roof. You’ll want something that can be easily turned off and on. It doesn’t have to be fancy and automatically shut itself off with a sensor, but it should be customizable to what you want.

There are plenty of other materials to consider, and all of them are available to aspiring solar pool heater owners.