solar-pool-heatersIf you are looking to add a solar heating system to your swimming pool and have questions about how to install solar panels, read on.

From simple, single on-ground panels for Intex pools to multi-panel roof mounted systems for in ground pools, I’ll explain the differences and how to get them up and heating your pool in a weekend!

To quickly qualify myself, I have four 2’ x 20’ panels on my garage roof and have installed dozens of solar pool systems on local residential pools. Plus, I work at InTheSwim – enough said.

What are Solar Heaters and How do they Work?

Pool solar panels are constructed of rows of small, hollow tubes made of black polypropylene (super strong plastic) or rubber that are seamed together to create a large surface area called a panel. pool-solar-panels

The sunshine heats the black mat and as water passes through, the heat is transferred to the water and returned to the pool.

Solar panels are an eco-friendly way to heat your pool 10-20 degrees warmer, with do-it-yourself installation, zero emissions – and with zero operational costs. With no gas or electrical lines to run, they are favored by pool owners everywhere!

Solar heaters come in a variety of shapes and sizes but the mechanics are basically the same. You can use your existing pump to circulate water through black tubing which naturally absorbs heat from the sun and sends that heated water back to your pool.

The more surface area the solar heater has, the more BTU’s of heat are generated. And the more BTU’s you generate, the greater the volume of water you can heat. Since a pool is open to the air, heat can be lost quickly. To combat the heat loss, it is recommended to over-size a solar pool heater.

One or more panels can be joined to create more surface area. Panels can be installed for above ground and in ground pools, positioned in a variety of ways, and controlled manually by turning a valve or automatically, with a solar controller.

Above Ground Pool Solar Heaters

Small Pools: If you own one of the ever-popular soft-sided pools like the pop-up or metal frame pools from makers like Intex, there are some quality do-it-yourself solar heaters from Game and Smartpool that are simple to install and take up very little yard space.

By coiling black tubing and covering it with a convex dome, the SunCoil solar heaters can be plumbed into your filter system by simply adding one more hose section after your existing pool pump & filter.


To install, all you need to do is turn off your pump and isolate your system by blocking off your skimmer and return or closing your shut-off valves. Next, disconnect the hose to the return and plumb it to the solar heater intake, then add another hose, fitting, and clamp from the solar heater output to the return fitting on the pool wall. Unblock your skimmer and return and turn the system back on and you are ready to enjoy the free heat!

The SunCoil solar heater shown right sits on the ground and can be tipped on 2 legs to maximize the best angle to the sun. A by-pass valve kit is included to shut-off the solar system during night or rainy days. The bypass kit also slows the water flow to allow the solar panel to maintain optimum heating temperature.

Large Pools: For larger, steel-sided above ground pools, there are a variety of manufacturers of much larger solar panels. These are long and flat, rigid yet bendable, and typically 2’W x 20’L or 4’W x 20’L – so you will need a long space to put them.aboveground-pool-solar-heater

Oval above ground pools lend themselves well to these systems as you can place them along the length of the pool, on a small rack attached to the braces or kickers. For round pools you need to be a bit more creative.

The panels can be laid flat on the ground, mounted to a fence, or you can build your own solar panel rack from angle iron, 2 x 4’s, PVC, or other frame materials. Over top of this triangular frame, attach plywood and mount your solar panels.

Inground pool solar heaters are packaged in rolls inside the box. After unboxing them you cut the securing strap carefully and unroll and lay them in the sun so they flatten out. It helps to have two people for this and putting a thick towel with a weight like a cinder block on each end will help hold it down otherwise they can spring-back into a roll. Depending on how sunny it is, they will flatten out quickly and stay flat. Once they are flat and warm they will be soft, so handle them carefully to avoid damaging the panels.

aboveground-solar-pool-heaterFor above ground solar heaters you can connect these panels the same way as the compact ones by adding just one hose, fitting, & hose clamp. The panels connect after your pump & filter and feed into your return line. If you want to locate them farther away from the filter, you simply need longer hose or pipe. You can use a pool vacuum hose, but without a swivel cuff, which will leak water.

If you are linking multiple panels, beware that some brands of above ground panels are split in the middle so water goes down and back in every panel so look for the stickers to identify the inlet and outlet. As you add more panels you will want to line these up so the water flows in, back and forth, and then out.

For other brands, water passes from one end to the other so there is no direction to worry about, making it even easier to plumb. Water goes in one end and out the other. Ends that are not connected to the water supply or an adjoining panel get capped. All pool solar panel systems come with easy-to-follow instructions.

aboveground-solar-pool-panelsPanels are most effective if they are angled 35-45 degrees to the sun for maximum heat collection. A southern facing exposure is best. A few straps or clips is all that is needed to secure them to a solar panel rack. Again, a by-pass system is recommended for these panels so you can dial in the flow rate or send the water around the solar panels at night or on a cloudy or rainy day.

To winterize a solar system, just disconnect the solar panels, blow out any remaining water with a wet/dry vac, roll them up and store in a freeze-free space like a basement or garage. If you leave them out all winter, cover them fully with a tarpaulin to block UV rays, which (ironically) weakens the material and can cause condensation inside of the panels.

Above Ground Pool Solar Panel Installation:

There are two types of solar systems for above ground pools, shown below – the SunCoil Solar Dome, and the EcoSaver solar panels. Both are extremely simple to install; you can set up your own above ground solar panels in under an hour.

aboveground-solar-pool-heater-installationsShut off pump and plug the skimmer and return line in your pool to stop water flow.

  1. Choose the location for the panel(s), where they will receive at least 6 hrs of sun per day. A southern-facing direction, unobscured by trees is best. SunCoil heaters should not be roof mounted, but the EcoSaver panels can be installed on a roof top (see below).
  2. The Universal Solar pool panels can be installed flat on the ground, but if you can build a small rack from wood, to mount them at an angle, your solar panel(s) will absorb more sunlight.
  3. four pool solar panels linkedConnect the return hose from your pump into the solar panel inlet, to bring the cold water into the solar heater.
  4. Connect the return hose from the solar panel outlet to the pool wall return, to bring the warm water into your pool.

Both solar systems are modular, that is – you can connect additional panels to each other. Out of one solar panel and into another. They can even be installed in different locations, or you can pipe your water to a remote location, it needn’t be up against the pool as shown in the pictures.

Solar Heaters for Inground Pools

There are solar panel kits available for in ground pools in many sizes;  4’W X 10’L or 4’W X 20’L. A good rule of thumb is to have roughly half of your pool’s surface area equal in panel square feet.

Example: A 20×40 pool has 800 sq ft of surface area, so 400 sq ft of solar panel would be a good target. This would equate to 5 of the 4’x20′ panels, or 10 of the 4’x10′ panels.. See our solar pool heater sizing charts for your pool size.

inground-solar-pool-heatersFor so many solar panels you need a good deal of space. However, you can always start with one or two and add more on later; just be sure to plan for space. Even one panel will add some heat.

In ground pools typically have much stronger pumps, so the panels can be mounted on a nearby roof, even 2 stories high. A garage or pool house roof or side of a hill is a good place or you might consider building an A-frame from treated lumber and plywood near the pump and filter area.

inground-solar-pool-heatingInstallation kits include roof mounting straps and hardware to secure them. All you need is a drill, caulk, and a helper to hold them in place while you work. Mark where your straps will go. You will want one on each end and then space out the rest equally. Drill into the roof or plywood on each side of the panels through the strap, caulk, and screw in the lag bolt or securing hardware (manufacturers have different hardware kits, but drilling is the same – although you may not always have to drill through the strap). You want the straps to overlap each panel and hold it down. Keep the holes a few inches away from the panel edges. Insert connecting fittings and caps between the panels and connect panels one by one.

Once the panels are secure, you are ready to plumb. Plumbing them to and from your pool can be accomplished with PVC, flex pipe, corrugated hose, or even garden hose. All the plumbing fittings you will need are available at most hardware stores.

inground-solar-pool-heater-plumbingIn ground base panel kits include fittings and check valves to keep the panels primed so when the pump turns on and off the water easily flows without air traps and without having to re-prime the panels each time. For snowbelt installations, it is recommended to install an array of solar panels with a slight pitch or angle, to facilitate drain down, for winterization purposes.

In Ground Pool Solar Panel Installation:

Installing an inground solar pool heater will take more time than the above ground units, because you need to do a little plumbing, and you will have more panels to connect together. Consult our solar panel chart to order the suggested amount of solar panels, which should be at least 50% of your pool’s surface area.

As illustrated in the pictures on top of the page, you don’t have to mount these solar panels on the roof of your house, if you don’t have a suitable roof location that receives at least 6 hours per day of direct sun. You can build a rack somewhere in the yard, or even on the back of your fence. It need not be next to the pool pump, although the further away from the pump, the more you will spend on plumbing pipes running to and from the panels. Perhaps a patio gazebo, providing a shady spot for relaxation and an out of the way location to mount your solar panels. solar pool collector infographic

  1. Unbox your panels and connect them together. Panels have separations to allow you to wrap around roof vents.
  2. Secure the panels to the roof with the included hardware. Attach the cross straps to hold down panels in high winds.
  3. Cut the return pipe after the filter, and glue on a one-way check valve and the 3-way diverter valve, included in the Solar Controller package.
  4. Connect another pipe on the opposite corner of your solar panel array. Run this exit pipe parallel to the top of the panels.
  5. Run the exit pipe off of the roof or rack towards the return line that was cut in step 3.
  6. Before connecting the exit back into the return line, glue on a one-way check valve, to prevent water from entering the panels in the opposite direction.
  7. After the check valve, connect the exit pipe back into the return line.

Pool Solar Panel Connections

Depending on the brand, the connections can vary, but when you buy a kit of 2 or more panels they will include the plumbing and hardware to connect the panels to each other.

Smart Pool solar panels have 1.5” threaded female openings on either end which you can attach a 1.5” male thread, while Fafco panels have barbed ends that protrude out at each “corner” or end that are sized for radiator hose and standard stainless hose clamps.

pipe-strapsIf you are installing on a rooftop, be sure to pick up enough fittings to make the transition over the eave of the roof, and down to the ground and some pipe straps to secure the plumbing run to the roof and wall. For masonry walls, use tap-con screws to secure the pipe clamps

From there you can find the appropriate connector pieces for your PVC, flex, or above ground pump & filter hose at your local hardware store.

Connect the line gong to the panels to a bypass valve after your filter for the water supply and tie the bypass line and returning solar heated water line into your return line with a tee fitting. Now you can turn on the pump, open up the by-pass valve and send the water to the solar panels.

If you haven’t worked until past dark, place your hand over the pool return, and you’ll start to feel the heat right away!

Solar Controller Installation:

A Solar Controller allows you to set a temperature dial, and includes temperature sensors, a 3-way Valve and Valve Actuator (automatic valve turner), to send water up to the solar panels only when conditions are optimum for gaining solar heat. When heavy clouds pass, rain begins to fall or at dusk each night, the actuator will turn again, bypassing the solar panels. For best results with an inground solar pool heating system, I highly recommend installing the optional Solar Controller.

  1. Mount the Solar Controller box on the wall or a sturdy post.
  2. Connect the power by plugging the cord into a grounded outlet.
  3. Drill a hole into the pipe before the 3-way valve, insert the water temperature sensor and clamp it to the pipe.
  4. Clamp or silicone the second sensor next to the solar panels, to monitor the panel temperature.
  5. Connect the wires from both sensors into the solar controller box.
  6. Remove the handle from the 3-way valve, to mount the actuator onto the valve.
  7. Connect the wire from the valve actuator into the solar controller box.
  8. Set the temperature dial and test the system.

Pool Solar Automation – Set it, and Forget it!

Goldline solar controllersYou can automate your solar pool heater by installing a wall mounted controller, valve actuator, and a water and air temperature sensor. Some popular models are Hayward’s Goldline Solar Controller and Pentair’s Sun Touch.

Solar controllers allow you to set your desired temperature. The sensors measure the air and water temperature. If the air temperature is greater than the water temperature, it tells the valve actuator to open the valve and send water to the panels to raise the water temperature. Likewise, if a hot sun is not available, the controller closes the valve so you don’t cool the pool down.

Controllers may also feature freeze protection and circulate water in the event that it is cold enough to freeze in the panels and potentially damage them.

Some controllers are also designed to control other features of your pool or spa like their pumps, heaters, lighting, etc. so you can automate when they turn on or off. Controllers can control valves to switch from solar panels to a gas heater or electric heat pump so you only use those when you have to – which maximizes your energy consumption and saves you money!

Frequently Asked Questions About Solar Pool Heating:

Q: Will I need to up-size my pool pump to push water up to the roof?
A: I have installed dozens of solar systems and never had to upgrade the pump. As long as you have a 1 hp pump or greater, you should have no problem, even pushing the water up 2 stories. You will notice that the filter pressure will rise 2-4 lbs on the pressure gauge, but most pumps can handle the extra resistance without a problem.

Q: I have a pressure-side pool cleaner, will this conflict with it’s operation?
A: If you have a booster pump type pool cleaner, it is recommended that you not operate it at the same time as the solar pool heater. The Solar Controller has a booster pump override to shut off the booster pump when the valve actuator opens to send water to the solar panels.

Q: Can I mount the solar panels on 2 different sides of the roof?
A: Yes, after exiting the first panel set, run a pipe to the second panel set, and so on, then back down to connect to the return line.

Q: Do I need to install the Solar Controller?
A: It is recommended for best results. If it starts to rain, or heavy clouds form, sending water to the solar panels will cool the water, and reverse the heat gains made earlier.

Q: What If I need to remove the solar panels to replace my roof?
A: The panels can be removed in a few hours, no problem.

Q: What about winterizing my solar panels?
A: Solar panels are installed with a slight pitch toward the exit pipe, with a air-lock valve on the opposite corner, to allow complete drain down during fall closing. If pitched correctly, there should be no need to “blow-out” the panels with air, although you can easily do this if you wish.

To summarize a solar pool heater installation process, plan your space and do some measuring, then select the size and shape of your solar heating system. Keep in mind that you may want to add more later on. Next, pick up the extra hoses or pipes and fittings needed so you have everything on hand when you are ready to set it up.

Once you have your solar pool heater set up, you start producing free heat from the sun without any impact on the environment and you will be swimming before your neighbors and long after they have closed their unheated pool!


Mike Cummings
InTheSwim Staff Blogger

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