The ideal temperature for swimming pool water is between 78 and 82 degrees Fahrenheit. Young children and the elderly will prefer the pool on the warmer end of that spectrum, as will those using the pool for any type of hydrotherapy. The ideal temperature for you, however, may be on the lower end of the range. In most parts of the country, the sun alone is not enough to warm a pool to 78 degrees, so you may need to use a heater or other means to raise the pool's temperature, especially if you want to start swimming early in the season or extend your swimming season into the fall. You don't need to heat your pool all the time, however, if you don't use it often. Instead, you can conserve energy by leaving the heat off and simply warm the pool quickly when you need it.
Gas heaters are less efficient than other types of pool heaters, and therefore, more expensive to run. They do, however, heat the pool more quickly than other heaters. If there are occasions when you need to heat your pool quickly, consider installing a gas heater and using it only when time is of the essence. You can always use your more efficient heater when you're not in a hurry and turn on the gas only when you need some extra power. Gas heaters can be used anywhere fast heat is desired but provide the most benefit when the average air temperature is below 50 degrees Fahrenheit.
Solar Blankets and Rings
A solar blanket is a great way to heat a pool and is an excellent choice for above-ground units that lack built-in heaters. Pools lose 75 percent of their heat through evaporation. Solar blankets stop this evaporation while absorbing and holding heat from the sun. You can use them to heat your pool by day and leave them on the pool to keep it warm at night. They use no energy and work well, but must cover 100 percent of the pool's surface in order to work.
Some pool owners prefer solar rings to solar blankets. Solar rings work the same way as solar blankets but are much smaller, at 60 inches in diameter. This makes them much easier to maneuver and store than blankets, especially if you are working alone. Solar rings must cover only 70 to 80 percent of the pool's surface and each one can generate 21,000 BTUs of heat per day.
Floor Return Lines
Having floor return lines in your pool helps to decrease the amount of energy and time needed to heat your pool. In many pool filtration systems, water is run through the filter and then funneled into return lines that take it back to the top of the pool. Since heat rises, the return lines are returning water that has already been heated to the warmest part of the pool in this system. Pool heating systems are much faster and more efficient if the return lines deliver the warm water to the bottom of the pool, where the heat will rise and warm more of the pool water.