Evaporation is by far the largest sorce of energy loss for a swimming pool.
When compared to evaporation, all other losses are small.
The Red Cross recommends 78o for optimal water temperature, but just to bump the temperature up to 82o will result in an energy consumption increase of more than 40% in an uncovered pool. A cover acts as a passive solar collector and can increase the temperature of the swimming pool water by 6 to 10 degrees.
By covering a swimming pool when not in use you can assume approximately a 70% savings which includes but is not limited to the following:
Reduces the amount of gas or electricity required to heat the pool
Reduces the amount of make-up water needed in the pool
Reduces the amount of electricity required to run the filtering system
Reduces the amount of chemicals used to sanitize and maintain the pool
Reduces the amount of service work on motors and equipment
Reduces the frequency at which liners and plastering need to be replaced
Reduces the use of dehumidifiers on indoor pools
Heat from the swimming pool water is lost through evaporation. Consider the following:
Heat Loss | |
| Evaporation | 70% |
Loss to ground and other | 10% |
| Radiates to sky | 20% |
You can assume a 90% reduction in heat loss with the cover in place.
It only takes 1BTU to raise 1 lb. of water 1o, but everytime one pound of 80o water evaporates, it takes 1048 BTU's out of the pool.
The evaporation rate depends on varying degrees of air, heat, shade and wind; as well as water temperature. For example, the higher the pool temperature and wind speed, and lower the humidity, the greater the rate of evaporation.
A 7 mph wind at the surface of the pool can increase energy consumption by 300%.
In dry and/or windy conditions the evaporation rate increases. In warm/humid conditions the rate decreases. Using a cover can keep these factors in check.
Using a pool cover can decrease water usage by decreasing the amount of make-up water needed by 30% to 50%. Other things to consider.
A 16ft. by 32ft. swimming pool can lose 180 gallons of water a week if uncovered.
Decrease in evaporation means lower water bills.
In some sunny states, a pool can lose its entire volume of water within a year from evaporation.
Because the cover keeps dirt and debris out of the pool, the filtering system doesn't need to operate as long as without a cover. There is not as much vacuuming required because there is nothing to vacuum. Because of decreased time the filter and pump motors run, they will require less electricity and need less servicing.
Reduce algae growth by reducing the amount of ultra-violet sunrays entering the pool water.
Chemicals are lost through the evaporation of the pool water.
By using a cover you can reduce chemical consumption by 35% to 60%.
One gallon of chlorine can evaporate in two hours without a cover, but may last for up to two weeks with a cover.
The UV (ultra-violet) rays from the sun are the main culprit in the degradation of pool finishes, whether that is plaster, vinyl liners, or fiberglass.