Home & Garden

The swimming pool: A splash of green is good for it

Swimming pool with diving board, sunshade and deckchairs (Digital)
Swimming pool with diving board, sunshade and deckchairs (Digital) Getty Images

Pools and "green" don't typically go together, unless you're talking about algae.

But technology and a recent push by the industry are making pools greener in a good way. Operating a pool can be a lighter load on the environment and the pocketbook. By changing some outdated equipment, a pool owner could save $350 to $700 a year.

Fewer chemicals

This year, Terry Aubuchon of Stilwell, Kan., made the switch from mixing chlorine with other chemicals to using a salt system to sanitize her back-yard pool. "From a maintenance standpoint, it's so much easier to deal with," said Aubuchon. "You just add a bag of salt, and the water feels and looks great."

The salt is converted into chlorine to kill bacteria using a salt-chlorine generator, which costs about $1,400. The old-school way of buying chlorine and other chemicals cost $350 to $500 a year compared to $8 for a bag of salt.

"It eliminates the chemical soup," said Roger Banks, owner of Banks Pools. His family has been in the pool industry since the 1960s. Still, less than half of all pool owners have made the switch to salt-chlorine systems.

Most people who talk to Aubuchon wonder whether her pool turns into saltwater like the ocean.

"Not at all," she said. "There's only a slight taste of salt."

Roughly a teaspoon of salt per gallon, to be exact. Chlorine in chemical form sends hundreds to the emergency room each year. (Last month, more than 30 children and adults were sickened by chlorine during a child's birthday party at a public pool in Mercer County.)

Salt-based chlorine is gentler on hair, skin and eyes. Salt chlorine also might be gentler on Aubuchon's pool liner. She's on her fourth one in 13 years; the average cost is $3,000.

A downside of salt chlorine is that it will corrode metal faster, so her ladder might rust. However, many pools built now use concrete or stone ledges for sitting and to help people get in and out.

Moss is another healthier sanitizing option for pools. Creative Water Solutions of Plymouth, Minn., tapped the water-cleansing power of moss and packaged it in a sort of "teabag" filter. The moss filter reduces the amount of chlorine needed by up to half, according to GreenBuilder Magazine.

More than 99 percent of bacteria in pools lives in a protective shield called biofilm. Moss does a better job than chlorine in fighting biofilm, preventing it from forming. This not only keeps the water clean but stops the corrosion and energy loss caused by biofilm.

Variable-speed pumps

California legislators recently began requiring new, efficient pool products; Energy Star is supposed to address pool equipment this year.

Pumping systems are what keep water in a pool relatively free of dirt, debris and bacteria. Older pumps run non-stop, so it's no surprise pools account for half of an owner's electricity bills.

New variable-speed pumps with permanent magnet motors and digital controls, about $1,300 installed, can save as much as 90 percent in utility costs compared to one- or two-speed pumps with induction motors.

Energy-efficient one- or two-speed pumps are available but should be properly sized to your pool's requirements.

More efficient heaters

If your pool heater is more than 5 years old, chances are a new high-efficiency gas heater could quickly pay for itself in utility bill savings.

New gas heaters produce five times more Btu with less gas. A new one costs about $2,100 installed.

Geothermal heat pumps for pools can save up to 80 percent in energy usage compared to a gas heater, but in the Midwest gas is preferable because it heats the water more quickly. Heat pumps, about $3,500 installed, can take three to four times longer to heat water but are less expensive to use, about 90 cents a day versus $6 or $7 a day for gas heaters.

Solar heating systems also are available and heat for free after the equipment is purchased. The drawbacks are that they require space, an area equal to half the pool. Solar pool heaters also require a number of panels, which generate peak output when the pool is often already warm enough.

Hybrid solar systems also are available, and so are advanced solar thermal designs that make it possible to integrate hot water, domestic space heating and pool heating. Prices vary according to property configurations in relation to the sun.

Pools and energy use

There are 4.5 million in-ground pools, which use $1.1 billion to $1.6 billion worth of energy a year. Our nation's residential in-ground swimming pools consume 9 billion to 14 billion kilowatt hours and 36 million to 63 million therms of natural gas each year, resulting in carbon dioxide emissions of 10 million tons per year — the equivalent of 1.3 million cars and light trucks on the road per year.

If all residential pools were upgraded to reduce pumping energy by one-third, and all heated pools were upgraded to reduce heating energy by one-third, the total annual savings would be more than $360 million. Carbon dioxide emissions would be reduced by at least 3 million tons.

Source: "Synergies in Swimming Pool Efficiency: How Much Can Be Saved?" from the Natural Resources Defense Council