Reviewed and Revised on 10/31/2013
Several features contribute to increasing the energy efficiency of a home swimming pool: proper selection, installation, and operation of the pump, filter, heating system, and cover.
You can reduce energy consumption and maintain a comfortable swimming pool temperature by using a smaller, higher efficiency pump and by operating it less. In a study of 120 pools by the Center for Energy Conservation at Florida Atlantic University, some pool owners reduced their original pumping bills as much as 75% when they used the energy conservation measures listed in the table below.
|Condition||Energy Use (kWh/year)||Cost of Energy ($/year)||Energy Reduction|
|Pump Replacement (downsizing)||1800||140||40%|
|Reduced Time (60%)||1200||100||60%|
|Combination of Above||720||60||75%|
Table courtesy of Home Energy magazine.
These reductions represent a typical pool in Florida using 8 cents per kWh. Due to Florida’s long swimming season, the average pool pump energy bill is probably higher than in many other areas of the country. Note that by both downsizing the pump and reducing operating time, you can achieve highest energy reductions.
The larger the pump, the greater your pumping and maintenance costs. Therefore, for increased efficiency, select the smallest size pump appropriate for your swimming pool. To choose the right size pump, consult a pool supplier’s design chart. When using the chart, match the hydraulic characteristics of the pump to both the piping and the pool’s flow characteristics. Note that if using a solar pool heating system, you also need to consider the need to pump the pool’s water to and through the collector(s).
In the Florida study, a 0.75 horsepower or smaller pump was generally sufficient for residential pools. If you decrease the pool circulation system’s hydraulic resistance, smaller pumps, which cost less, can be used by:
- Substituting a large filter (rated to at least 50% higher than the pool’s design flow rate)
- Increasing the diameter or decreasing the length of the pipes, or replacing abrupt 90-degree elbow pipes with 45-degree ones or flexible pipes.
You can reduce the pump’s electricity use by up to 40% by decreasing the pool circulation system’s hydraulic resistance.
Operating the pump
Pool pumps often run much longer than necessary to mix chemicals and remove debris. As long as the water circulates while chemicals are added, they should remain evenly mixed. In addition, depending on pool location (e.g. near trees or some other source that generates water quality issues), it is not necessary to recirculate the water every day to remove debris, and most debris can be removed using a skimmer or vacuum. Further, longer circulation doesn’t necessarily reduce algae growth. Using chemicals in the water and scrubbing the walls are the best methods to accomplish this.
Water Filtration is a major cost of owning a swimming pool. Try reducing your filtration time to 6 hours per day. If the water does not appear clean, increase the time in half-hour increments until it does. In the study cited earlier, most people who reduced pumping to less than 3 hours per day were still happy with the water’s quality. On average, this reduced the electricity demand for pumping by 60%.
Programmable timers can be set to control the pump’s cycling. If debris is a problem, use a timer that can activate the pump for many short periods each day. Running the pump continuously for, say, 3 hours leaves the other 21 hours a day for the pool to collect debris. Several short cycles can keep the pool clean all day. Check with the local utility company to find out what times they suggest are the best off-peak hours in your area.
Note: If you use the services of a maintenance staff, make sure that they do not change the timer’s settings.
Keep the intake grates clear of debris. Clogged drains require the pump to work harder, which uses more energy. Clean your filter according to the manufacturer’s recommendations. Sometimes the operating sound of the pump changes and is detectable when it is operating under more strain.
Options for heating the pool include solar energy, fossil fuels (LP gas, natural gas or oil), and heat pump. Each option has its own advantages and disadvantages. Solar pool heating is the most cost-effective use of solar energy in Florida. The cost effectiveness of the various options will vary for different climate zones and cost of power or fuel.
Solar power used for heating the swimming pool
Solar Pool Heater: A solar pool heating system usually costs between $3000 and $4000 to buy and install. They typically last longer than gas and heat pump pool heaters. Your actual cost and payback depend on many factors. Check with your local utility company to see if they offer rebates.
Gas Pool Heater: A gas pool heater is most efficient when heating a pool for short periods of time and is ideal for quickly heating pools. Therefore, gas pool heaters can be a good choice for pools that are not used on a regular basis. Unlike heat pump and solar pool heaters, gas pool heaters can maintain any desired temperature regardless of the weather or climate.
Heat Pump Pool Heater: Heat pumps use electricity to capture heat and move it from one place to another. They do not generate heat. Heat pump pool heaters generally cost more than gas pool heaters, but they typically have much lower annual operating costs because of their higher efficiencies. With proper maintenance, heat pump pool heaters typically last longer than gas pool heaters.
Covering a pool when it is not in use is the single most effective means of reducing as much as 50%–70% of the pool’s heating costs.
Pool covers not only decrease pool heating costs, but they also can minimize the pool’s chemical use by 35%-60%, conserve water by reducing the amount of make-up water needed by 30%-50%, and reduce cleaning time by keeping dirt and other debris out of the pool. When choosing a cover, look for durability, ease of taking on and off, price, warranty, material transparency, insulation value, storage need, and safety.
For more information, contact your professional pool dealer to help you make informed choices on all aspects of a pool operation.