Conserve Energy and Heat Your Swimming Pool with Solar Energy

Swimming pools provide a great way to exercise and beat the summer heat. and maintaining a pool, however, also means relatively high added to your household's budget. There are several ways that you can reduce operating and costs, lower water consumption, and conserve heat if you heat your pool. Many people heat their pools to extend the swimming season and/or to keep it at a temperature that they are personally comfortable with. This lets them enjoy the full value from their pool. Solar pool heaters are an option to heat the pool with “clean” energy from the sun, and can reduce heating costs.

Optimizing Water Filtration and Circulation Pumping

A study by the Center for Energy Conservation at Florida Atlantic University shows that pool owners can save energy and maintain a comfortably heated pool by using smaller and higher efficiency pumps, and operating pumps less each day. In this study of 120 pools, some pool owners saved as much as 75 percent of their original pumping bill when they used both conservation measures.

Sizing the Pump Right

When a pump wears out or can't be repaired, a pool owner typically installs a larger one, thinking that “bigger must be better.” Instead, a larger pump may increase the costs of pumping and maintenance. To choose the right size pump, consult design charts that match the hydraulic characteristics of the pump to both the piping and the pool's flow characteristics. A local pool supply dealer should have access to these charts.

The Florida study shows that a 0.75 horsepower or smaller pump is generally sufficient for residential pools. Smaller pumps, which less, can be used if you decrease the pool circulation system's hydraulic resistance. This can be done through one or more of the following ways: substituting a large filter (rated to at least 50 percent higher than the pool's design flow rate), increasing the diameter or decreasing the length of the pipes, or replacing abrupt 90-degree elbows with 45-degree elbows or flexible pipe. These types of changes can slash up to 40 percent off the pump's use of electricity.

Circulating the Water

Another way to save energy is to reduce the pump's operating time. Pool pumps often run much longer than necessary. Pool owners need to understand the reasons behind circulating the pool's water. Circulating water keeps your pool's chemicals mixed. However, as long as the water circulates while chemicals are added, they should remain evenly mixed with minimal daily circulation. Secondly, circulating the water keeps the pool free of debris by drawing water out and through the filter. It is not necessary to recirculate the water completely every day to remove debris and clean the water. One complete circulation usually takes between 6 and 12 hours per day. But this may be longer than necessary since most debris either floats or sinks, and can be removed with a skimmer or vacuum. After about an hour, most of the pumping power is wasted by circulating clear water and does little to improve the water's quality.

Furthermore, longer circulation does not necessarily reduce the growth of algae. Instead, using chemicals in the water and scrubbing the walls are the best methods. In the Florida study, most people who reduced pumping to less than 3 hours per day were still happy with the water's quality. On average, this saved them 60 percent of their electricity bill for pumping. Combined with using a smaller size pump, pool owners saved up to 75 percent of their original electricity bill for pumping water (see table above).

One last simple measure for saving is to use an accurate timer to control the pump's cycling. Use a clock that can activate the pump for many short periods each day if debris is a problem. Running the pump continuously for, say, 3 hours leaves the other 21 hours a day for the pool to collect debris. Several short cycles keep the pool cleaner all day.

Summary of Recommendations

Pool owners can save a great deal of money by:

  • Choosing the smallest pump and the largest filter suitable for their pool
  • Decreasing the hydraulic resistance of the pool's circulation system wherever possible
  • Circulating the water with the pump for the shortest time possible (often fewer than 3 hours)
  • Installing a timer.

Keep in mind, however, that all pools are different. Circumstances such as special cleaning and heating needs, climate, pool size, and usage all affect a pool's circulation, as well as the potential for saving money.