Solar Pools - Using Free Energy For Heating A Pool

by Pool Builders on 01-06-2011 in Articles

Solar water heaters are common these days but did you know you can use the sun's free energy to heat your swimming pool? There are many pool solar panel systems available to suit practically all pool types and budgets. Is a solar pool heater the right choice of pool heater for you? There are a few good reasons why you should use a solar pool heater:

  • zero operating cost
  • long lifetime
  • easy to fit to an existing pool
  • can even be used to cool a too-warm pool
  • solar pool heater DIY kits are available.

There are also a few reasons why you should NOT use a solar heater:

  • won't work in overcast conditions or shadows
  • requires a lot of space
  • puts extra strain on the roof
  • official approval may be needed for roof mounting.

How does a solar pool heater work? In simple terms, water flows from the filter and through the solar collector panels where it is the sun heats it. It is then returned to the pool through the piping already in place. It does take a bit of effort for the pump to push the water up to roof height so check the pump capacity (the "head" must be greater than the maximum height the water will reach) before a system is installed. The main reason anyone will install a solar pool heating system is to take advantage of the free energy from the sun. With gas pool heaters being fairly cheap around the $500 to $2,500 mark and electric heat pumps coming in the $2,000 to $4,500 range there can be a big difference in price with systems of a similar output. The big plus is a solar system should have paid for itself within about 3 to 5 years. With a lifespan of around 20 to 25 years the savings over time are obvious -- very roughly around $30,000 or so. From an environmental perspective, apart from the environmental "footprint" of the manufacture of the system there is no further harmful effect on the environment. No burning of gas and no need for power stations to produce electricity. The pool pump would be running anyway so there is no significant change.

The major downside of a solar system is it can not be used "on demand". Gas heaters and heat pumps just need the flick of a switch and you are heating your pool rather being at the whim of the weather. The main use of a solar pool heater is to lengthen your swimming season, if you want to swim all year and you don't have 365 days of sunshine then a solar heater may not be for you. The use of a pool cover will add enormously to the efficiency of a solar (or any) system as it reduces heat lost through evaporation by about 80%. There are solar heaters which will run along with another heater so you can have the best of both worlds -- taking advantage of the sun's energy would certainly offset the increase to your gas or electricity bill. A bit more complicated and more expensive to set up but worth thinking about. Solar heaters require a lot of space to set up a decent array of solar panels -- around 50% of the pool surface area is generally recommended.

For example, a 20' by 40' pool (800 square feet of surface) would require about 400 square feet of collector surface or 10 panels at 4' by 10' so check first you do have the necessary unshaded area either on a roof or the ground. Solar panels are modular to if you decide later you need more heating capacity you simply add more panels. If you intend to roof-mount a solar system, make sure the roof will be strong enough to take the extra strain. Collector panels themselves don't weigh a lot (about 15 to 20 pounds each) but add in some fittings and the water flowing through and you do finish with a substantial weight. Also think about wind conditions -- extra strain exists in windy conditions. In some areas you may need permission from local council or government before fitting a roof-mount solar system -- check before you buy! If you live in a hot climate and your pool water reaches the point where it warms you up instead of cooling you down, you can use a solar heater system to cool the water. All you need to do is run the filter system at night. The water flows through the panels which will radiate the heat from the water back into the air. For the do-it-yourself enthusiast, there are kits and books available which can lead to a much cheaper solution. Usually they consist of readily available materials and using basic hand tools and skills. If you are not afraid of heights or getting your hands dirty, there could be a solution for you. Just remember, commercial systems come with guarantees. In conclusion, solar pool heaters give an environmentally friendly way to increase the enjoyment of owning a swimming pool for little ongoing cost. There are systems to suit most budgets and pool types. Combining a solar system with a gas or heat pump system will have you in the swim all year at a greatly reduced cost. Using a pool cover will help a solar heater perform better.

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