Swimming Pool Blog

Solar Pool Blankets

by Rob Cox, February 22, 2010

Solar Pool Blankets

Image credit to Kevin Osbock - https://www.flickr.com/photos/kevino/with/1732178684/

Bubble Wrap, invented in early 1960 by engineers Marc Chavannes and Al Fielding, was initially conceived as some sort of safety wallpaper. Today, over 250 Facebook pages are devoted to the love and fun of Bubble Wrap, and just recently, on the 50th anniversary of Bubble Wrap, the Sealed Air company rolled out a one day production of gold colored Bubble Wrap.

If you haven't figured it out by now, Bubble Wrap was the mother of today's swimming pool solar blankets. As the story goes, during the mid-1970s Sealed Air's researchers came up with another innovative use for the company's air cell technology. The Sealed Air Solar Pool Blanket was essentially a big sheet of Bubble Wrap that was placed on swimming pools. The Solar Pool Cover allowed the sun's rays to heat the water and sharply reduced the evaporative loss of water and treatment chemicals. By 1977 the Solar Pool Blanket was generating 6 percent of company sales.

Sounds simple, right? Just lay this piece of floating plastic on the pool, and you "harness the sun's energy" for free pool heat. Or even better, the solar blanket retains the heat put into the pool by a roof mounted solar heater or a gas pool heater. Especially at night, solar blankets can help prevent heat loss, and in areas of high wind, they become a necessity just to maintain the pool temperature. The best part, however, is that a solar blanket in full sun can add 10 degrees to the pool water temperature during the day.

It is pretty much that simple, however there is a "hassle factor" to the use of solar blankets on the pool. Unless you have a small pool, two people (or one with "skills") are needed to install and remove the solar blanket. Using a solar blanket reel makes this job 90% easier, but then you have this long reel on one end of the pool, not especially attractive or otherwise useful. And solar blankets will need occasional cleaning, especially if you have trees around the pool. The leaves that fall onto the solar blanket need to be removed as the blanket is removed, otherwise as you roll it up, the leaves can get stuck on the bottom the blanket, and enter the pool when the blanket is reinstalled.solar blanket colors

The original solar pool covers were available in any color - as long as that was Blue. Nowadays, you can find solar blankets in many colors, coatings and air pocket shape. Does it make a difference? This author has seen no data to support the claim that clear allows more of the sun's rays to penetrate "deep into the pool water", for example. So the jury is out on whether a black, silver coated, clear or blue solar blanket will deliver the best results. Maybe it's just a fashion contest!?!

Solar blankets are sold in rectangle sizes for in-ground pools, so how do you size a solar blanket for their pool? Measure the pool's widest width and longest length. Buy the size the covers both measurements, and trim to fit with sharp scissors or a razor knife. If your pool is longer than 50' or wider than 30' - then you either need a custom solar blanket, or you can buy two smaller blankets and use them together. If you want, you can use waterproof tape to join the two sections together.

To install an inground solar blanket on a free-form shaped pool, it gets a little bit trickier. Unbox the blanket and stretch it over the pool tight enough to pull out the folding wrinkles. Use weights or water bags at certain points to hold it in place, but allow the blanket to float on the surface of the pool. Using the coping stones or inside edge of the pool as a template, work your way around the pool with a sharp razor knife running the edge of the pool. Move slowly around the pool, keeping the solar blanket taut and straight as you cut. Ball up the excess material, recycling it if you can as packaging or wrapping or insulative material.

For aboveground pools, solar blankets are pre-cut and into rounds and oval sizes. No cutting necessary either for rectagular pools. If your blanket is a little short or doesnt cover every square inch of water surface, don't worry too much, the effect will likely be minimal.

To care for a solar blanket, and get more than just a season or two from it, follow these tips to protect it from harsh water chemistry and UV rays. Yes, UV degradation is an ironic nemesis of the pool solar blanket.  

  • Always remove the solar blanket before shocking the pool, and leave it off until chlorine level returns to normal.
  • Always store the blanket indoors during the winter, or use the winter solar blanket cover.
  • When rolled up on the reel, cover your blanket with a protective solar blanket UV cover.

And one more tip - please make sure to fully remove a solar blanket from the pool before use. Although rare, drownings have occured with disoriented swimmers trapped beneath a solar blanket.