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Pool heaters: What would we do without them?

By Marcelle Dibrell

Water temperature is perhaps the most critical parameter for bather comfort in a swimming pool

A change of only a few degrees is significant for swimmers, and makes a difference in whether the water is inviting.

The reason that water temperature is so crucial is because body heat is lost much faster in water than it is in air of the same temperature. Because water has a much higher thermal conductivity, combined with the fact that it is denser than air, by some estimates, a body in water can lose heat up to 200 times faster than in air.

Furthermore, optimal temperatures range not only from person to person, but are also dependent on pool use. Different activities change the optimal water temperature.

For example, competitive swimmers prefer, on average, water temperatures between 79° to 81°F. Younger swimmers tend to want the water a little warmer while senior citizens want it warmer yet — at around 88°F.

Pool heaters also extend the swimming season. For thousands of pool owners in the country, September marks the beginning of the end of the swim season

For some pool owners, the swimming season can be doubled with the simple addition of a heater. 

It is for these reasons that heaters are one of the most important additions to a pool. And for spas, of course, the heater is the most important component.

Pool heaters are sized to raise the temperature of a given volume of water from 20°F to 40°F. Generally the rise in temperature should be gradual — about 1°F per hour. 

Correctly sizing the heater is essential to its performance. If the heater is too small, it will heat the water too slowly. On the other hand, if the heater is too big, it may take up too much space on the equipment pad and the operational costs will increase

Like the pool itself, a heater is a luxuryHaving a constant and reliable water temperature comes at a cost, and depends on the type of fuel employed.

There are advantages and disadvantage to each type of heating device. All of the choices — including gas, electric, heat pumps and solar panels — will extend the swimming season and make water comfortable

The following articles contain basic information that service technicians may need when dealing with pool heaters.

Paid subscribers have full access to the complete coverage on pool and spa heaters. Contact our circulation department at 949-916-0292 or email for details.


Pool Industry Expo 2014, Sept. 25-27, Monterey, Calif.

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