This is the time of year that I hear quite a few people saying that their solar pool heat is not working. In most cases, the system is working well, but they may not be comfortable swimming at the current pool temperature. The easy solution would be to ask them to turn off their solar pool heater and report back with the temperature after a few days. I bet it would be much colder!
Generally speaking, an unheated pool will be approximately the same temperature as the Gulf of Mexico. The average historical Gulf temperature in Naples, FL in December is 68°F. Today, December 20, 2011, the current Gulf temperature is 69.6°F. A typical well-sized and oriented solar pool heating system will raise the pool temperature about 10°F above the Gulf temperature, which would imply a temperature of almost 80 degrees.
To get the current Gulf temperature in Naples, FL, go here: http://www.solarsouthwestflorida.com/gulf-of-mexico-temperature-naples-fl/
A pool cover will add a few extra degrees to the pool temperature, especially when nighttime air temperatures dip below 65°F. In fact, when temperatures get below this level at night, all or most of the heat generated by the solar panels (or heat pump, or gas heater) during the day simply escapes into the cold night air.
Why do people come to the conclusion that the solar pool heat is not working when their pool temperatures are well above the Gulf temperature? I think there are a few factors at play.
- The average Gulf temperatures in Southwest Florida in October, November, and December are 81°F, 73°F, and 68°F. This is a precipitous temperature drop in a short period of time, and people recall swimming comfortably “just a few weeks ago.”
- “The water coming out of the jets feel like the same temperature as the pool water.” There is a common misconception that the water returned to the pool should be and needs to be significantly warmer than the pool water. The fact is, solar pool heating works on a high-volume, low temperature rise principal. The temperature differential can vary significantly. As long as the water returned to the pool is warmer than the pool, you pool is being heated. Do you think you can perceive the difference between 80 and 81°F water by holding your hand underwater? The water may not spend enough time on the roof to rise in temperature significantly, and that is okay! Over time, the pool will warm up. Keep in mind that a cover will help retain much of this heat gained during the day, and the cumulative effect over days will make your pool much more comfortable.
- Temperatures and weather patterns vary from year to year. Seasonal residents may remember swimming on Christmas one year, while the next year may be unbearably cold.
Our service department is observing covered solar pool heated pools this time of year in the 80-84°F temperature range. Depending on the size of your system, size of your pool, orientation, micro-climates, shading, and many other factors, your system’s performance may vary.
Don’t hesitate to call your dealer if you think something is wrong, but consider whether your system is working properly or not using the information above!
If your pool is not reaching temperature levels described above, there may be something you can do:
- If you do not have an automatic controller, Make sure that your pump is running or your solar is on only when the sun is out and the roof temperature is likely higher than your pool temperature. Otherwise, you may be cooling your pool! A solar pool heating controller will automate your pool heater and ensure you are not unintentionally cooling your pool.
- Your system may be undersized to reach your heating expectations. Adding panels will increase performance. You can also use panels with a higher BTU rating.
- There may be shading on the panels from trees that have grown.
- If you are seeing NO heating above the Gulf temperature, there may be a legitimate problem with your system. Give your dealer a call!