Guide to Pool Covers
By Stephanie Powell
Covers are best known for what they keep out of your pool -- from filter-clogging leaves and other debris to accident-prone children and pets.
But another benefit comes with what pool covers keep in your hands: Money, by reducing heat loss, water evaporation and even maintenance chemical consumption.
How much can a cover save you?
Dollars and Sense
• According to the U.S. Department of Energy (DoE), the most effective way to reduce pool heating costs is with a cover. That's because a covered pool acts like a giant solar collector, absorbing heat and transferring it to the water. Studies show that a covered pool can have a solar heat gain of up to 15 degrees F; that can reduce overall heating costs as much as 70% compared to an uncovered, similarly sized pool -- especially when using a cover with greater insulation value. To maximize passive solar gains, consider running your pump and filter system while the cover is in place; this circulates the warmer water throughout the pool.
• An uncovered 16- by 36-foot pool loses up to 180 gallons of water per week to evaporation -- the capacity of three completely filled home bathtubs. A cover, meanwhile, can reduce this evaporation between 30% and 50%, reports the DoE.
• A covered pool extends the sanitizing power of chlorine and other chemicals, reducing consumption by 35% to 65%, according to studies.
Nearly all covers help reduce costs in varying levels, but for that other type of savings -- someone's life -- products must meet specific requirements by the American Society for Testing and Materials (ASTM International) to qualify as bona fide safety covers. ASTM-approved safety covers must hold the weight of two adults and one child within a 3-foot diameter -- approximately 485 pounds. They must also have adequate drainage to prevent drowning hazards if a child or pet wanders onto them, and not have any opening large enough to allow a child to slip through.
Cover choices tend to be limited for aboveground pool owners:
Solar blankets are the most basic and inexpensive. Resembling giant sheets of bubble wrap, they are placed over the pool surface, and their translucent material allows sunlight to warm the water while preventing heat from escaping. Though lightweight and easy to remove for daily pool use, solar blankets are designed primarily for heat conservation -- not for cleanliness or safety.
Winter covers are the next level of protection. Plastic fabric completely covers the pool, tied tightly around the perimeter or weighted with sand bags; they are not intended for daily use. As the name implies, these covers shield the pool from winter conditions and provide for easier season-opening cleanup. If your budget allows, look for one with UV stabilizers, mildew inhibitors and reinforced seams.
Solar blankets and winter covers are also available for inground pools. But others can be used whenever the pool is not in use or supervised -- no matter the season -- and are available for all types of pool configurations and shapes. The most dramatic difference is how the cover attaches to the pool or deck.
Tie-down covers, also called "manual covers," stretch across a pool and are "tied down" to deck-mounted anchors via springs and adjustable straps. Made of solid vinyl or mesh fabric, tie-down covers form a taut barrier around a pool. Even though they are traditionally used for winterizing inground pools, newer lightweight materials make them more practical for everyday use. Still, with larger pools they can be heavy enough to require two people, so try handling one before buying it.
Tie-down covers can be custom-designed to fit over steps, raised spas and water features, but generally require about 3 feet of decking around the pool for the securing anchors.
Track-style covers are a great choice for everyday use -- especially with rectangular pools. (Installing a track-style cover over a non-rectangular pool is trickier, but possible.) Made from reinforced coated vinyl, these covers work by sliding over the pool along a set of tracks. Installers typically mount low-profile tracks on top of the existing pool deck or, for a premium price, they may cut through the deck to install a nearly invisible below-surface system. When retracted, the cover rolls up onto a reel or into a sunken housing unit at the end of the pool. Track-style covers are available in two versions:
• Semi-automatic covers use a motor-driven reel system but also rely on muscle power and hand tools, such as cranks and poles, to roll the cover back and forth.
• Automatic versions are powered by a hydraulic motor that slides the cover open and closed, by simply pressing a button or turning a key. Some homeowners tap into the power of these covers by opting for remote controls that not only allow them to operate the pool cover, but also turn on outdoor lighting and crank up water features.
To upgrade from a semi-automatic to an automatic track one, you'll need to purchase the operating mechanism, motor and controls and have the system professionally converted. However, the converted system can generally use the existing tracks and fabric.
What About Spas?
As with pools, a hot tub or spa cover offers plenty of benefits -- including heat and chemical retention, cleaner water and a safer environment. Because a spa is well insulated on its sides and bottom, most heat loss comes from the water surface itself. When left uncovered, a spa can lose massive amounts of heat in a short amount of time. Therefore, use a spa cover as you would a pool cover -- ideally, whenever it is not in use.
When shopping, search for a cover made from mildew-resistant, marine-grade vinyl with a high-density foam core wrapped in moisture-barrier plastic. These materials prevent the cover from absorbing water and becoming too heavy to move. If you live in a cold climate, look for a product dense enough to support a heavy snow load without caving in.
Cover lifts, which make removing the cover simple, are a smart and convenient option. The most popular lifts attach to the spa and have a bar on which the spa cover folds. Another removal device uses supports to slide the cover off of the spa, while a third design uses a curved metal support to cradle the cover to one side of the spa. An advantage of this type of lift is that it does not cause stress on the cover's hinge.
Photo courtesy of Meyco Products, Inc.