Solar Swimming Pool Covers Do More Than Heat Your Pool

Many people think the only purpose of solar swimming pool covers is to heat your pool. In fact, solar covers, or solar blankets, don't really heat your pool at all. They keep it warm by trapping heat from the sun in the pool, and that's only one of their benefits. They can also help save you money on water and chemicals.

According to the Department of Energy, "Almost all of a pool's heat loss - about 95% - occurs at the surface, mostly through evaporation to the air and radiation to the sky. Evaporation is by far the largest source of energy loss. Evaporating water requires tremendous amounts of energy. It only takes 1 Btu (British thermal unit) to raise 1 pound of water 1 degree, but each pound of 80ºF water that evaporates takes a whopping 1,048 Btu of heat out of the pool."

That's where pool covers come in. By trapping the sun's natural heat in the pool, and preventing evaporation and heat loss, solar pool covers can raise your pool's temperature by up to 15 degrees. The key is keeping the cover on when you're not swimming. When we leave our cover off at night, our pool can lose four degrees in a single night. That means the sun needs to warm the pool up four degrees the next day before it even reaches the previous day's temperature. With the solar cover on, we usually only lose about one degree of temperature. That means the next day the sun only has to bring the water up one degree before the pool can start warming beyond the previous day's temperature.

In the beginning of swimming season, this can make a huge difference in how quickly your pool reaches your preferred temperature. Our pool is always warm enough to swim before the pools of friends and acquaintances who don't use solar covers. That's a great benefit of a cover, but it's not the only one. By helping to heat your pool quicker and keep it warmer longer, solar covers can extend your swimming season and allow you to maintain your pool at a comfortable temperature all season long.

The US Department of Energy says solar swimming pool covers can also:

* conserve water by reducing water loss through evaporation by 30%-50%
* reduce the pool's chemical consumption by 35%-60%
* reduce cleaning time by keeping dirt and other debris out of the pool
* help increase temperature of pool by 10 - 15 degrees.

Covers are most helpful in climates where the air is drier and cooler because that's where heat and water loss due to evaporation is the greatest. But no matter where you live, a solar pool blanket is a good investment and will save you money while allowing you to swim longer and in warmer water. If you don't have one, what are you waiting for?

Solar pool covers are available for both in-ground and above-ground pool and are inexpensive, starting at about $20 for the smallest, thinnest covers for above-ground pools and going up to several hundred dollars for thicker covers for large in-ground pools. But it's money well spent. The DOE estimates a solar cover will pay for itself in about a year in energy savings, not to mention the benefits of being able to swim longer and in warmer water.

You can find solar blankets at virtually any pool shop, or you can shop online for a wider selection of solar swimming pool covers at stores such as poolproducts.com and In the Swim

Solar swimming pool covers are available in several colors and thicknesses, and sizes for virtually all pools. The thicker the cover, the longer it will last, but you'll also pay more upfront. In the long run, however, you could save money. Here's an example taken from an online pool supply store in February 2010.

8-mil solar cover for 15x30 pool with a three-year warranty - $67.99
12-mil solar cover for 15 x 30 pool with a SEVEN-year warranty - $94.99

I'm not the kind of person who buys an extended warranty with every major purchase, or even pays much attention to the manufacturer's warranty in many cases, but this is one case in which the warranty - which is based on the thickness and sturdiness of the cover - is important because your pool cover WILL deteriorate from the sun and chlorine and need to be replaced. If your local pool supply store is like mine, you may only find the thinner covers in stock because they wear out more quickly, which means you'll have to come back and buy another one sooner. Shopping online is a great way to compare prices and get the cover that's going to fit your needs and budget. You can also usually find deals that lower the price of your cover if you buy it with a solar cover reel, and you can also frequently get free shipping to make it an even better bargain.

You may eventually decide to purchase your cover from your local supply shop anyway, but at least you'll be making an informed decision.

Pool covers are usually rectangular, but just because your pool is an odd shape doesn't mean you can't use a solar swimming pool cover. It just means you can't buy a nice rectangular cover, throw it on the pool and be done with it. Instead, you'll need to measure the length and width of your pool at the longest and widest points. Then go buy a cover that will fit the maximum dimensions of your pool. When you get home, pull the cover onto the pool and grab a pair of scissors. Then simply cut the cover to the shape you need. It's easy and doesn't take long.

The photo here shows my swimming pool (with the solar cover off). As you can see, it's not rectangular!

Depending on the size and shape of your pool, it may be easier and/or cheaper to buy two smaller covers and piece them together, but whether you decide to cut one or more covers to fit your pool, it's easy to do!

The easiest way to manage a solar pool cover is to buy a reel that allows you to roll it up when you want to swim and unroll it when you want to cover the pool again. Reels are VERY nice! But they don't work well on some pools. My pool, for instance, has a jumping rock at one end and the pool entrance at the other end, so there's no place to put the reel. It's also very narrow at the entrance and wide at the foot. So even if we had a mobile reel and wanted to pull it into position to uncover the pool and then move it while we swam, the shape of the pool makes it fairly unmanageable.

If you can't afford a reel or don't have room for one, it's easy enough to just pull your solar cover off and fold it near the edge of the pool while you swim. But if you can afford it, a reel is REAL nice.

Solar covers are great during the months when your pool is getting a lot of sun and you want to keep the heat in. But if you really want to expand your swimming season, a solar pool heating system may be the solution. For instance, from late May until August, my swimming pool gets full sun until about 6 pm. But by September, the sun is shifting so the shadow from the house prevents the pool from getting as much sun. The outside temperature may still be warm enough to swim (it was in the 80s last year when we went to pick pumpkins in late October!), but the pool cools off rapidly because there's not enough sun on the pool to keep it warm.

So one of these days I'm going to invest in a solar pool heat system so we can swim until Halloween! The advantage of a solar heating system is that they are frequently mounted on your roof so you can take advantage of any sunny days even when your pool might be shaded.

The Sierra Club says, "Solar pool and spa heaters are simple technologies that require little maintenance. A typical system costs $3,000 to $4,000, and will pay for itself within two to seven years. What's more, these heaters reduce greenhouse gas emissions, air pollution, and demand for fossil fuels."

"A solar pool heating system is very different from a solar blanket because a solar blanket does not actively heat swimming pool water," says an article on "In the Swim. "A solar blanket helps your pool retain the heat generated from the sun hitting your pool water, and a solar pool heater actually ads heat to your entire pool. A solar pool blanket will only help to warm the top few inches of water in your pool. A solar pool heater is constantly circulating and warming the water from your entire pool."

Solar heating systems are simple. Your pump circulates pool water to the solar panels, where it is heated by the sun, and then the warm water is circulated back into your pool.

If you really want to extend your swimming seasons, a solar pool heating system with a solar cover is the ultimate solution.