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How To Install A Pool Solar Heater

Swimming in freezing cold water is great if you are a member of the polar bear club - the other 364 days per year it would nice to have water above 80 degrees (26 degrees Celsius). The problem is that swimming pool heating is extremely expensive. Gas heat as used in gas pool heaters can cost well over $1000 per month if you run your heater indiscriminately and this is in addition to the high purchase and installation costs for gas heat. Pool heat pumps are another good idea for some people, depending on the climate and electrical costs of the area that you live, however electric heat pumps are less than ideal in many areas.

If this sounds like your situation, or you are in a position where heated water in your pool is a luxury that you are not willing to pay for, then pool solar heating is just what you need. Of all the forms of pool heating it is the least expensive to buy, the least expensive to install, and is the only one that operates without any ongoing "fuel" costs. Of course the downside is that pool solar heating is completely dependent on warm weather and sunshine, and provides the least amount of total heat to your pool water versus any other method of pool heating. If you have reasonable expectations for how much heat you will get from solar, basically around 10 degrees F under ideal circumstances, and you have some place where you can mount a solar mat then solar pool heating is something you should absolutely consider.

Even if you have a gas pool heater or electric heat pump you should still consider adding a solar heater to reduce the ongoing costs of heating your pool water - a small upfront investment will pay for itself completely over time





How Much Will A Solar Heater Heat The Pool?

To answer this question you would need to consider a number of situationally specific variables unique to your pool installation. For that reason you can only ask this question in a general sense. As a rule of thumb it is reasonable to hope for as much as 10 degrees F increase in temperatures however it is possible to get less or more depending on a number of factors. The amount of direct sunlight, the surface area and volume of the pool, amount of cross winds, night time low temperature, size of solar grid, ambient daytime temperature and current pool water temperature will all impact the bottom line of how much your pool water will warm up. If you want to use solar heating for your pool then it becomes critically important that you learn to conserve any heat that you do have - this is the single most important aspect of getting the most out of a pool solar heater.

By far, the vast majority of heat from your pool water will be lost during night time when the temperature drops dramatically. If you allow heat to escape like this every night then you will never realize any benefits to adding a solar heater (not to mention spending a small fortune on heat if you are paying for heat with gas or electricity). If you want to use a solar heater on your pool then you absolutely, positively MUST use a solar blanket on the pool every night. Owning a solar blanket and leaving it rolled up on the end of the pool doesn't count either - you need to actually use it! Use of a solar blanket at night will dramatically reduce the energy loss from winds and cold temperatures and this is in fact how a solar blanket is intended to work. Many people think that a solar blanket is supposed to heat pool water directly, which it can but in actuality a solar blanket is designed to work primarily as a method of heat retention - specifically at night.




10 - 18' Round Pool Solar Covers
12 x 24' Pool Solar Cover
16 x 32' Pool Solar Cover
18 x 36' Pool Solar Cover
20 x 40' Pool Solar Cover
25 x 50' Pool Solar Cover
30 x 50' Pool Solar Cover

If you have a shape other than round or rectangle then you would buy the next size up cover and lay it (float it) on top of the pool. Stretch out all of the wrinkles and ensure that you have the blanket oriented correctly on the pool, then go around with a brand new, extremely sharp razor knife and cut the blanket to fit your pool. If you have a size or shape of pool that can not be accommodated with any standard size blanket then you can seam in (add) sections to your cover using this Blanket Fastening Kit which is also the same kit you use to attach a solar blanket to a solar blanket tube roller. You can order a separate fastening kit and use this to add sections to your solar blanket by "sewing" them in. Simply fold over the sewn in sections before rolling up the cover.




If you want to make your life a lot easier, as well as get more longevity out of your solar blanket, then consider adding a solar roller to your pool setup. In theory you do not need one of these however it saves a great deal of wear and tear on your solar blanket being dragged on and off of your pool which is the most likely time that your cover will get damaged.

It used to be that solar blanket roller reels were extremely expensive but as you can see with this example the prices are much more affordable then they once were.

Pool Solar Heater Plumbing

When it comes time to install the plumbing configuration for a pool solar heater this can be done in either a minimal, manually operated method - or a fully automated method that involves temperature probes and motorized valve actuators that will automatically turn the solar heater on and off. Either method is easy enough for an intrepid do-it-yourself pool owner to install themselves.


Manual solar heater plumbing installation - If you want the bare minimum cost and ease of installation for your pool solar heater then all you need to do is create a "3 zone bypass" in your system. In the most simple of terms a 3 zone bypass is an orientation of 3 ball valves installed such that you can send all water to the solar heater, none of the water to the solar heater, or some to each. This is how almost all peripheral equipment should be installed on a pool so it is worth the effort to understand this simple plumbing configuration.

standard pool equipment plumbing configuration zoned pool equipment plumbing configuration

In this example the 3 zone bypass can be seen leading up to the new solar heater. In each place marked with an "X" you would install a PVC Ball Valve to regulate flow. The concern with this installation is it would be possible to "dead head" the pump. If you were to close the valve going to the solar, and close the "bypass valve" or the X on the original feed line to the salt cell, then the water would have no options to flow and dangerous pressure could build. A single zone, or two zone bypass configurations are possible, which have slightly less user control but do involve a make-before-break three way valve instead of 3 individual valves as pictured here. However, if you are looking for the most straight forward and lowest cost installation then a standard 3 zone bypass as pictured is the way to go.


Automatic solar heater plumbing installation - Essentially an automatic solar pool plumbing installation is the same concept as a manual 3 zone bypass except that you will be adding a motorized valve actuator to handle the changing of valve orientations for you. The addition of a solar controller will act as the brains of the operation and tell the valve actuator when to do its thing.



Pictured here is the control box unit which is only part of the total system that you will need. In addition to this you will require a 3 way valve to which you will need to also buy and install a motorized valve actuator and temperature sensor cables. Together this will provide you with the ability to control the flow of water to the solar heater, automatically, with the system sensing when the heater is in the sun. You can also order all of these items together as a Solar Pool Heating Kit.

With this installation you would not use three ball valves as with the manual installation, instead using only one motorized three-way valve. Where the manual plumbing configuration is a 3 zone bypass, this method is a single zone bypass since only one control valve is being used.

motorized valve actuator for pool solar MVA orientation with check valves for pool solar heater

In the second example here the addition of a check valve is added. Without the check valve in place the system would exert back pressure on the filter from the weight of the water in the line going to the solar heater. The reason why in this example check valves are being used instead of manual controlled ball valves like in the manual 3 zone bypass example is for system protection. If the ball valves were in the closed position to and from the solar heater, but the automatic controller turns the bypass valve, then you would have a situation where the pump is being dead-headed and dangerous pressure levels and likely a system blowout would occur. Use of check valves is strongly encouraged, as are the addition of PVC unions on both the line to and the line from the solar heater. This will allow a way to break into the system for draining and winterization of the solar heater.

There are many other valve orientations and configurations that will all "get the job done" and there may be a better way that illustrated here to add a solar heater to your existing plumbing - this is just one possible way to connect the solar. You can also add things like spigot drains and winterizing ports as needed for your system requirements.


What Is The Best Pool Solar Heater

From a do-it-yourself perspective it is more than possible to purchase a few hundred feet of schedule 40 PVC pipe, ideally black in color (or painted black), and glue these together to form a grid on top of your roof. This will work extremely well and might be the cheapest possible way to install a pool solar heater. Other benefits include being able to size the grid to accommodate any roof space size that you have available to you. The disadvantages are that with this many glued joints it could be possible to make a small error that results in a leak and it will be up to your skill level to make this grid not an eyesore on your roof. For most people looking to add a pool solar heater it will be more likely that you go with prefabricated solar collectors.


Solar collectors like this usually come in 2' x 20' panels of which you buy as many as your pool will need depending on the pool volume. Calculating how many solar collectors you need will require a little guesswork - there is very little hard data available about how much heat you will actually realize in your pool since there are simply too many variables. Combine that with the fact that most solar heater manufacturers are going to claim dramatic results and you may very well end up not getting the performance that you were hoping for. Much like with any form of pool heater, you are better to have too much heat generating ability as opposed to not enough.

Using a general guideline add one 2' x 20' panel for every 5000 gallons of pool water. A 12 x 24 pool might be around 10,000 gallons and would use 2 panels where a 20 x 40' pool might be slightly over 30,000 gallons and you would want as many as 6 solar panels.

To see how to calculate your pool volume read this article on swimming pool basics


Space Saving Pool Solar Heaters

There are a lot of solar heater products on the market that meet the description of space saving however it is very important to consider that the total area of your solar collector will have everything to do with how well the system performs. Tiny solar heaters like these 24" x 24" pool solar heaters are going to deliver very little, if anything, in the way of heat to your pool. You either need to have a tiny swimming pool or have many of these units to make any kind of significant difference to your water temperature. The same can be said for these Intex 4' x 4' solar panels. While they might work in theory, you would need two or three of these at minimum for every 5000 gallons of water - which is not going to be practical for most people looking to add solar.





Swimming Pool Steve

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