How Do I Know How Many Solar Pool Heating Panels I Need?

There are some rules of thumb that will tell you how many solar pool heating panels you will need. The answer varies based on a few assumptions, and the number of panels is determined based on several factors. Don’t assume that your neighbor’s system will perform the same way for your home, and your budget is also a consideration.

Assumptions Used To Determine Solar Pool Heating Panel Sizing

We need to set expectations properly from the start, so answering a few questions is key to sizing a system appropriately:

  • How long do you want to extend your swimming season. Do you expect year-round swimming, or do you just want to extend your season? Most people request year-round swimming, but then realize it is impractical and not necessary given the coldest days we experience here.
  • What temperature are you generally shooting for? Note that this may change by season. Most people will throw out a number rather arbitrarily (85ºF seems to be popular). In reality, pool comfort is relative to the outside air temperature and weather, and a wide range of temperatures can be comfortable for swimming.
  • Are you planning on using a pool solar blanket and an automated solar controller? A pool blanket can reduce your investment in solar panels and provide faster heating and higher ultimate temperatures. An automated solar controller will optimize the operation of your system and provide convenience.

Factors That Affect How Many Solar Pool Heating Panels You Need

There are several factors to consider, and the importance of each factor may vary. Some of the major factors are:

  • The surface area of your pool. The volume is not particularly important, as most heat is lost from a pool’s surface, and we are working to overcome heat loss with any heating system.
  • The orientation and roof pitch where the panels are intended to go.
  • Shading issues that may reduce the effectiveness of the system.
  • Exposure to wind (pool and panels).
  • Screened or unscreened pool.
  • Available flow rate from existing equipment.

Ball Park Estimate for Solar Pool Heater Sizing

Solar Pool Heating Panels in Cape Coral, FL
A Typical 6-Panel Solar Pool Heating System for a 12’x24′ Pool in Southwest Florida.

If there is one factor that can be used to size a solar pool heater and ensure customer satisfaction, it is matching the surface area of the solar panels to the surface area of the pool. We shoot for 100% for orientations of east, south, and west. If you size your solar pool heater on this basis for any typical roof in Southwest Florida, you will get pretty close to what we consider satisfying performance for year-round swimming on days where people are actually likely to swim (i.e. the outside air temperature is conducive to swimming).

A very common pool size in the area is 14’x28′, meaning you need to match a surface area of 392 square feet. If you are using 4’x12′ panels (48 sq ft each), you need about 8 or 9 panels. From there we can make adjustments for ideal or sub-optimal orientation, shading, and the other factors listed above. Of course, if you don’t have enough roof space, we may be constrained, but even an “undersized” system can provide a satisfying customer experience. This is especially true for the best solar panels that harvest the most sun under sub-optimal conditions (ours, of course).

By using the 100% coverage rule of thumb, and making adjustments based on site conditions and experience, we can tell you how many solar pool heating panels you need to heat your pool. As you might imagine, bigger is always better. There is a point of diminishing returns, however, and systems need to be suitably matched to your existing equipment (unless you plan to upgrade your pool pump, filter, or plumbing). Larger solar pool heating systems tend to help your pool reach the maximum temperature more quickly each day, but the maximum temperature does not go up drastically with more panels because they become less effective as the pool gets warmer. If you plan to use a pool solar blanket, a larger system may be less important.

To be safe, you should probably consider the advice of your solar professional after an evaluation of your site. The 100% coverage rule will get your pretty close, but a more detailed look is always a good idea. We can perform an aerial photography analysis of your site using 3D computer modeling prior to an on-site evaluation, and tweak the system sizing according to any findings that would affect your pool heating satisfaction.

  • Comment (2)
  • Dennis Zupanc says:

    I’m looking at a solar system for a 14X28 pool. 2 roof surfaces available for the collectors, one west, one east. Total sun. South side is the front of the house ,myself and my neighborhood association will not allow the panels to face the street. I like to swim at 87 degrees. I would like to extend my season for 6 weeks in the both the spring and the fall if possible.

    • Jason Szumlanski says:

      Hi Dennis,

      I’m not sure where you are located, but you need a local pro. Local factors are going to be important. Here is what I can tell you…

      First, if you are in Florida, a HOA can’t prevent you from putting panels on a south roof, even if it faces the street. If you don’t want them there, that’t your choice. You will just have to live with subpar performance. You sound like a good candidate to install solar electric panels to offset an electric heat pump if you live in a climate that supports efficient heat pump operation.

      Second, putting solar pool heating panels on an east and west roof would be counterproductive. You could actually be heating panels on one roof and cooling them on the other. In the winter, the sun is low in the sky, and there will be times when the sunny panels oppose shaded panels. In the summer it might be fine, but when you need heating most, this configuration would be counterproductive.

      Anyway, it’s also counterproductive to give you advice without knowing where you are and knowing your local conditions and other factors. Find a local pro is my best advice.

      Jason

  • Mark Rambis says:
    Your comment is awaiting moderation. This is a preview; your comment will be visible after it has been approved.
    So is there a formula to put in all “requirements “, then figure panel requirements? Do panels come in other than “14×48”?
  • Dennis Mysliwy says:
    Your comment is awaiting moderation. This is a preview; your comment will be visible after it has been approved.
    what brand name solar panel do you sell? I currently have HiTech panels that are nearing 5 years old. 3 panels have started leaking and needing replacement and several 2″ pipe joints have started leaking. I’m told it will cost me $175 per panel and another 100 per panel labor. The leaks have ruined my roof and now it’s needing replacement. I’m looking to replace all the panels but wanting a higher quality panel that are less prone to leaking and better warranty if they do. Can you advise about your panels and warranty. I live in North Port FL. Do you provide service in North Port. The black piping used cannot be easily repaired with new sections due to swelling. How do you overcome this problem.

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