If 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 easy set 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 4 – 2’ x 20’ panels on my garage roof and have helped install 12 – 2’ x 20’ panels on a custom plywood and fence post A-frame solar rack. 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.
The sunshine heats the material 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 up to 10-20 degrees warmer, with do-it-yourself installation, and 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. Thus, 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 this, an old saying applies: “Bigger is Better!”
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 or automatically.
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 the plastic tubing and covering it with a convex dome, the Solar Pro solar heaters and curved Solar Arc heater can be plumbed after your filter 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. 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!
Both of these models sit on the ground and can be tipped on 2 legs to maximize the best angle to the sun. If you are adding 2 or more or have a 1 HP pump or greater, there is a by-pass valve kit that can be installed before the solar collector so you can divert some of the water straight to the pool. This takes the pressure off of the collector and slows the flow so the water can absorb more heat.
The bypass kit is also useful when there is no sun or if you run your pump at night when the collector would be cold – so you avoid cooling off the pool!
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 x20’L or 4’W x 20’L – so you will need a long space to put them.
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, you secure plywood and secure the solar panels to the plywood.
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 will spring back and re-roll. Depending on how sunny out it is they will flatten out quickly and stay that way. Once they are flat and warm they will be soft so handle them carefully or you may puncture the material.
For above ground installations 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 Don’t use a pool vacuum hose as they often have a swivel cuff on one end and will leak.
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 so you know where the” in” is and the “out” is. 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 solar panel systems come with easy-to-follow instructions.
Panels are most effective if they are angled 45 degrees to the sun for maximum heat collection. 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 you 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. Left out all winter, they suffer UV degradation, and you take the chance of condensation building up inside which can freeze and crack the tubing.
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.
For 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.
Installation 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.
In 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 harsh winter climates of the far north, it is suggested that they be drained, blown, removed and stored where they won’t freeze. Moisture from the air can condense in the tubes and freeze and crack even if you have blown them completely dry. Moderate winter areas can leave the panels in place after winterization.
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.
If 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 dark, place your hand over the pool return, and you’ll start to feel the heat right away!
Pool Solar Automation – Set it, and Forget it!
You 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 the sun is blocked or goes down, the controller closes the valve so you don’t cool the pool off.
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!
So 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!
InTheSwim Staff Blogger