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Conservation and Your Swimming Pool

This article courtesy the Los Angeles Department of Water and Power

Swimming Pool Conservation

graphic people floating in poolSince the swimming pool and its equipment are major users of water and energy at your home, you have a unique conservation opportunity.  By reducing the pool's energy and water use, you will benefit the environment, as well as receive substantial savings on your utility bill.

Put your pool on a energy diet -- your enjoyment of your pool will remain the same while you save!

This booklet is designed to help you save energy, water and money while still enjoying your swimming pool.  Many of the tips are from the California Swimming Pool Industry Energy Conservation Task Force (SPEC), which is a nonprofit association of swimming pool builders, manufacturers, service technicians and retailers.

Filter Pumps

Length of Operation

A pool filter pump is often one of the largest users of electrical energy at a home.   You can save energy and money by reducing the operating time of the filter pump.

Time requirements for pool filtering vary from home to home due to differences in pool volume and equipment, the amount of use and environmental factors.  As a general rule, one complete water turnover every 24 hours will provide adequate filtering for a non-solar, single family residential swimming pool.

You can determine the number of hours required for one complete filtering cycle of your pool water by referring to "How to Determine Pool Volume in Gallons" below and to the "Table to Determine Time (Hours) Required for One Complete Turnover of Pool Water" that follows.

After you have determined the number of filtering hours required for your pool, compare that figure with the actual filtering time shown on your filter pump time clock.  If the filter pump is operating the same amount or fewer hours than you computed, you are already practicing good energy management.  However, if you find that you are operating the filter pump more hours than necessary, you have an excellent opportunity to save energy and money by resetting the filter pump time clock tripper devices to the reduced hours of operation.

Chart of monthly pool pump energy use

Example:  A pool owner has a 1-1/2 HP filter pump motor and filters the pool 12 hours a day, using 588 kWh per month.  By reducing the filtering hours to four per day (which uses 196 kWh monthly), the pool owner realizes a monthly savings of 392 kWh.  If your electricity cost was 10 cents per kWh, that would be a savings of $470.40 per year.

Rather than computing the turnover time, you may prefer to follow the pool filter operating recommendations established by the California Swimming Pool Industry Energy Conservation Task Force - which are as follows:

"Reduce filter operating times to no less than 4 to 5 hours per day during the summer and 2 to 3 hours per day during the winter period.  This will reduce annual electrical consumption by 40 to 50 percent.  Normal and heavier swimming use may require as much as eight or more hours filtration per day.  Should water clarity or chemical imbalance indicate inadequate filtration, immediately operate the filter until acceptable water clarity has again been established.  If additional filtration is still indicated, increase filter operating time in one-half hour increments until the water remains clear and properly balanced chemically.  When the pool is being heavily used, it is recommended that the pool be operated manually and that the filtration system be run under such conditions.  Under no circumstances should the water quality of any swimming pool be so poor that the main drain cover is not clearly visible from the deck."

Time of Use

As a pool owner, you can help reduce the demand for electricity by operating your pool pump during off-peak hours.  The demand for electricity is highest from late morning through early evening.  By not operating your filter pump during these hours, you can help reduce the demand on the Department's electrical system; which may delay the need for new power plants and help keep future rates low, benefiting all customers.

Also if you are served on the Time-of-Use rate, making sure the filter pump does not operate during peak hours can result in a lower electric bill.

Time Clocks

A time clock is a necessity in giving you day-to-day, automatic control over the time-of-use of the filter pump.  If your pool doesn't have a time clock, install one today and the investment will pay for itself in a reasonable period of time.

Good pool energy management includes checking the time clock every month of so to determine that the trippers are set correctly and that they are securely in place.

How to Install or Reset Time Clock Trippers

  1. Turn off electric power to the time clock.

  2. Install or reset trippers to show the minimum or selected operating hours and off-peak time-of-use.  Be certain trippers are securely fastened.

  3. Make sure the time clock is set to the correct time of day.

  4. Turn on the electric power to the time clock.

Preventive Maintenance

Follow a regular program of preventive maintenance for pool pump and filter.   Backwash or clean the filter as recommended by the manufacturer to obtain maximum efficiency.  Maximize water recirculation by removing foreign materials from the strainer baskets in the pump and skimmer regularly.

Automatic Pool Cleaners

Usually 3 to 4 hours of daily operation during the summer and 2 to 3 hours daily in the winter are sufficient.  Start the pool sweep 15 minutes or more after the filter pump is running and stop the sweep 15 or more minutes before the filter pump.  On unusually dusty days, increase cleaning time in half hour increments until the pool is clean.  Use a wall brush and leaf skimmer frequently to help the cleaner along.

Decorative Lighting

Turn off or reduce the use of decorative lighting in and around pool areas when you are not using the pool.  However, one light in the pool is a good security and safety measure.

Pool Heating

Water Temperature

Maintain a 78°F or lower temperature.  Be certain that you are using an accurate pool thermometer.

For pools which have only weekend use, water temperature should be reduced by 8 to 10 degrees during the week.  The thermostat should be reset to the 78°F level before use.  Heat pool only during the summer swimming season.  Shelter the pool where possible from the prevailing winds by using well trimmed hedges or other landscaping, cabanas or fencing as windbreaks.

Solar Pool Heating

Swimming pool heating is the most popular and cost-effective application of solar energy.  As conventional fuels become more expensive, solar energy becomes a more attractive way to provide heat for your pool.  If your pool is in direct sunlight now, it is already using and storing solar heat.

In an active solar pool heating system, filtered pool water is pumped into the tubing of the collector panels.  The sun's heat is transferred from the panels to the water, and the heated water is returned to the pool.  Automatic controls are available to turn on the system when there is enough sun to heat the pool water and off when no heat is needed.

In many cases, the existing pool filter pump and plumbing can be used to circulate water through an added-on solar system.  Solar pool heating systems are especially effective during the summer months and can assist a regular pool heater in the spring and fall.

A solar pool heating system can be a significant investment.  However, with the cost of conventional fuels on the rise, the long-range cost effectiveness is becoming more and more attractive.  The savings from energy not purchased may more than pay for buying the solar equipment over its useful life.

If you are considering the installation of a solar pool heating system, compare price estimates.  Ask for references and investigate the quality of the systems.  Be sure you understand the performance guarantee.

Preventive Maintenance

Follow a regular program of preventive maintenance for pool heaters.  An annual inspection and, if applicable, de-liming of the heat exchanger when necessary will maintain heating efficiency.

Pool Chemicals

Add chlorine during the evening hours whenever possible.  With reduced filtration time, it is particularly important to maintain an adequate chlorine residual or level at all times.  To do this on pools with erosion type chemical feeders, it may be necessary to supplement chlorine feeding by hand.

Maintain pool PH between 7.2 and 7.6.  Make certain that the pool is treated annually with 30 to 50 parts per million of cyanuric acid conditioner (chlorine stabilizer).

Pool Water Conservation

Install an evaporative pool cover and keep your pool covered whenever it is not is use.   This prevents water evaporation and can save hundreds of gallons of water a month.   The cover can also reduce heating bills by preventing night heat loss and will save on chemicals too.  Pool covers come in a wide range of types and costs, so consult your pool service company, builder or pool supply retail store.  Make sure that it fits properly because the cover is the #1 water and heating fuel conservation device.

Reduce splashing. Caution swimmers to guard against splashing on decking and lawns.

Plug the overflow line when the pool is in use.

Re-evaluate the frequency of backwashing if your pool has no separation tank.  Most people backwash more frequently than necessary.  This wastes water.  Some pool filters do not have to be backwashed at all; they can be taken apart and cleaned, even though this process is less convenient.

When cleaning around the pool use a broom, not a hose.

Turn off the tile spray device on your automatic pool cleaning equipment.  A good deal of that spray evaporates before it hits the tile.  Scale formation on tile is reduced when the spray is turned off.

How to Determine Pool Volume in Gallons

Measure the length and width of your pool and determine the average depth.  Using the measurements you obtained, compute your pool's volume in gallons by following the steps in the appropriate example below.

Compute rectangular pool water volumeRectangle Shape Pool

Step 1.  30' length × 15' width × 5.5' average depth = 2475 cubic feet (cf) capacity.

Step 2.  2475 cf capacity × 7.5 gallons per cf = 18,562 gals.* (or 18,000 gals. in round figures) in pool volume.

Compute round pool water volumeCircular Shape Pool

Step 1.  20' diameter × 20' diameter × 6' average depth = 2400 cf capacity.

Step 2.  2400 cf capacity × 5.9 adjusted gallons per cf = 14,160 gals.* in pool volume.

Compute kidney-shape pool water volumeKidney Shape Pool

Step 1.  12' width + 18' width = 30' width.

Step 2.  30' width x 40' length x .45 (factor) = 540 sq. ft. (surface area).

Step 3.  540 sq. ft. × 5.5' average depth × 7.5 gals. per cf = 22,275 gals.* in pool volume

Oval Shape Pool

[image]Step 1.  30' long diameter x 15' short diameter x 5.5' average depth = 2475 cf capacity.

Step 2.  2475 cf x 5.9 adjusted gals. per cf = 14,602 gals.* in pool volume.

(If pool has sloping sides, one additional calculation in needed:  gallons (pool volume) x .85 (adjustment factor) = pool volume in gallons.)

Table to Determine Time Required for One Complete Turnover of Pool Water

Before using this table, it is necessary to have the following information:

  • The pool volume in gallons.
  • The filter's pressure in pounds per square inch (psi), which can be read on the pressure gauge located on the filter unit.
  • The filter pump motor horse power rating (hp) which can be found on the manufacturer's name plate located on the pump cover.

Example:  Reading the table below from left to right, a 20,000 gallon capacity pool, with 15 psi of filter pressure and a 1 hp pump motor would need 4.5 hours filtration time for one complete turnover (or filtering cycle) of the pool water.

Pool water turnover time

* Times are rounded to the nearest one-half hour and are for an average efficiency pump motor.
   Time required to keep water clear may vary due to environment and other factors.

We would like to thank the  Los Angeles Department of Water and Power for allowing us to reproduce this article!

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