In the not-to-distant past, a pool was like a bad tattoo on the backside of a green home. The water waste, the energy-sucking pool pump, and the chemicals ran in direct opposition to the tenets of sustainability. But with recently adopted technology and a pool industry ready to move toward more holistic sustainable methods, it is possible for your buyers to own a restful water wonderland without the environmental guilt.
The implications of a sustainable pool industry are huge. Today, there are 4.5 million in-ground pools, which use $1.1 to $1.6 billion in energy costs per year, according to the
Natural Resources Defense Council (NRDC) in its report,
“Synergies in Swimming Pool Efficiency." Our nation’s residential in-ground swimming pools consume 9–14 billion kWh and 36 to 63 million therms of natural gas each year, resulting in CO2 emissions of approximately 10 million tons per year—or the equivalent of 1.3 million cars and light trucks on the road per year.
And it won’t stop there: The industry claims it will continue to grow by about 6% a year, especially in pool-popular states such as California, Florida, Texas, Arizona, and New York, which are home to the majority of residential pools.
The pool industry is considering green policies following two mandatory standards set by the
California Energy Commission. The
Consortium for Energy Efficiency (CEE) has announced that it will launch a swimming pool initiative in 2010. And the EPA is expected to follow suit with an Energy Star program. In fact, Energy Star selected pool pumps as one of only two categories it intends to address in 2010.
The upshot of even modest changes to the way pools operate is compelling. According to NRDC, if all residential pools were upgraded to reduce pumping energy by one-third, and all heated pools were also upgraded to reduce heating energy by one-third, the total annual savings would be worth more than $360 million. Carbon dioxide emissions would be reduced by at least three million tons—the equivalent of removing all of San Antonio’s cars from the road for one year.
Pump It Down
Consider this fact shared by Jeff Farlow, program manager for energy initiatives at
Pentair Water Pool and Spa. “If you took the worst 30-year-old refrigerator and replaced it with the best performing refrigerator on the market, you wouldn’t come anywhere near the savings you’d get from replacing a single-speed pump with a variable-speed pump.”
The typical pool pump used today is single speed. It is sized to take on the toughest job, like running the jets on the spa or cleaning the pool. Trouble is, it runs at that level even when it’s not necessary. “Typically, a pool needs much less energy and water to do standard filtration,” Farlow explains. “The pumps are running every day at max speed for once in a blue moon when you turn the spa on.”
A variable-speed pump can be programmed for the exact requirements of each pool task and the optimal speeds tend to be slower speeds, with the ideal pump running longer at lower speeds and adjusting to requirements only when needed. Reducing the speed in half reduces the energy use to 1/8 the higher speed.
The NRDC estimates that in a community with a four-month pool season, upgrading from a single-speed to a variable-speed pump can save the average homeowner $350 a year. The organization conducted a study on Pentair’s IntelliFlo variable speed pump and noted that the system reduces energy use up to 90%.
Pentair reports customer savings as high as $1,360 annually, with an added advantage of quieter operation (about 7–10 decibels).
The rub against variable-speed pumps is the cost. “They cost twice as much,” admits Farlow. “But it will pay for itself in a year or two.” He notes that as pool industry sales staff become more familiar with the payback, they will be able to sell the system on its energy-efficiency benefits. “The push for this will come from consumers. They understand the impact on their power bill and how much the pool pump plays into their power bill.”
Farlow points to the example of
Green Builder’s show home, The ReVISION House, which debuted at the Las Vegas IBS show in January. “We replaced the 1.9 kW pool pump with a pump that runs at 180 watts, eight hours a day and realized a $1,100 [annual] savings.”
Skip Phillips, owner of
Questar Pools and Spas, was an alpha test pool for variable pool pumps and calls it a success. “My pool has filtration, a 14 kW PV system, and 1/2 horsepower pump. Everyone said I would need more power to make it work,” he says. “The variable frequency keeps the operating costs down. You’re talking about an eight-hour turnover where the equivalent water is filtered and then it’s stagnant for 16 hours. With in-line sanitation and low chemicals and the pump running 24 hours, you can run at a low flow rate for less money.”
But that’s not the only good news on the efficiency front. Other technology changes and best practices can help, too. For example, new sophisticated control systems allow pool owners to operate their pools outside peak energy use periods. In addition, the pump itself can run more efficiently if larger, straighter pipes, sweep elbows, lower pressure backwash valves, and oversized filters are used.
Turn Up the Heat
To reduce the amount of energy needed to heat a pool, the first step is siting. If possible, place the pool in a location that captures the maximum sunshine. Shield the pool from wind to avoid debris from trees and loose soil from causing the filtration system to run more often.
Heat pumps and solar pool heaters are two options for heating water. But before we get into that, consider pool covers. They help reduce heating energy and water losses from evaporation. The most common cover is an inexpensive “bubble wrap” type cover that can be manually rolled across a pool. Many people consider these unattractive and difficult to roll up, which, experts say, means they are less likely to be used.
Though it can be expensive (about $5,000), an automatic retracting pool cover is a smart idea. It cuts energy use significantly and minimizes the amount of debris in the water, which cuts filtration operations and lessens the need for chemicals. This type of cover is also more attractive and provides a degree of safety. (A person can step on it and not fall through.)
Using the sun to heat a pool makes sense. Scientists estimate that the sun energy that hits the surface of the earth every minute is greater than the total amount of energy humans use every year. But taking that ample energy and converting it to heat a pool can require space—usually an area equal to at least half the pool. There are also the usual limitations of solar orientation of the house and available roof to accommodate the array.
Bruce Baggin of
B&B Pool & Spa operates in New York, where there is a 20-week pool season. “It makes sense to use a solar system. It’s not that expensive—about a two-year return,” he says. “The only downside is that it requires a number of panels.”
The other drawback is that the panels generate peak output when the pool is often already warm enough, so they need to be designed and oriented carefully to extend the heating season but not attempt to operate under freezing conditions, notes NRDC. In addition, systems that are too small require a natural gas backup while systems that are too big would be expensive and require a “heat sink” where excess heat could be dumped.
On the plus side, advanced solar thermal designs make it possible to integrate domestic hot water, domestic space heating, and pool heating into a single system with glazed collectors. While more complex and expensive than solar pool heaters, these systems have a number of advantages. They can be sized to meet 100% of the year-round domestic hot water demand, providing supplemental hot water to domestic space heating during the winter and supplemental hot water to the swimming pool in the summer, thus avoiding the need for a heat sink.
“A combined space heat, hot water, and pool heater is good for those who are interested in sustainable energy versus ‘renting’ their energy from the utility,” says Dale Dennis, president of
Home Energy Checkup in Hamilton, Ohio.
This system uses more attractive flat plate collectors that look similar to skylights, which can be mounted on the roof or ground mounted. And though you would still need a large surface area for pool heating, it would be much more attractive than the plastic panels.
“Proper sizing should be a balance of aesthetics and sustainability,” Dennis adds. “A solar heat, pool, and water heating system can integrate with existing fossil fuel appliances to provide heat year round for whatever you need.” (See “By the Numbers,” below.)
A low-tech but noteworthy option for heat and water savings is
Heatsavr. The product is biodegradable and odorless and forms a one-molecule-thick layer on pools, which keeps the water from evaporating and the heat in the pools. According to the company, tests have proven heat bill savings range from 15.5% at a 50-meter municipal pool to 40% at a low-use condo pool. The company repackaged Heatsavr into disposable plastic fish, which float in the pool dispensing the product. Go with the original application of pouring it into the pool
to keep the disposable plastic out of the
waste stream.
Reduce Your Salt
Chlorine and salt generators (also chlorine) are the two mainstays for keeping pools clean. Unless your client wants a natural pool (see
“Au Naturale,” below), they will have to use these chemicals, which are dangerous, can corrode equipment, and are bad for the environment.
Rick Chafey of
Red Rock Pools & Spas, points out that the salt generators, which produce chlorine, can reduce pool durability. “The problem is that salt is corrosive to metal, rock, concrete, and steel. Over time it will degrade the surfaces. We do higher end pool projects with a lot of natural stone versus acrylics.”
Fortunately, a newer “technology” enables you to reduce the amount of chlorine in a pool by up to half: moss. Creative Water Solutions has a product that is essentially moss in a teabag, which naturally cleans pool water. Check out the company’s
website for the science behind it , but in a nutshell, more than 99% of bacteria in pools live in a protective shield called biofilm. Moss prevents biofilm from forming, which not only keeps the water clean, but it also stops the corrosion and energy loss that is also caused by biofilm.
“The moss system is the only truly green renewable water treatment product out there,” claims David Knight, founder of
Creative Water Solutions. “We use a species of sphagnum moss from New Zealand to control pH and heavy metals.” A large supply of moss is available in Minnesota, there just isn’t a harvesting industry in place yet. The company is working on that issue and hopes to be locally sourcing the material soon. King just received the results from a commercial pool that tested his product. “They [formerly] spent $78,000 on chemicals, and with moss they spent $38,000. The other thing the report showed is that they saved $100,000 in overtime costs because pool didn’t ‘go bad.’”
Now That the Guilt is Gone
The implications of velvety, chemical-free water in combination with a heating system courtesy the sun, and an Energy Star-qualified pump system that uses a fraction of the energy it used to, means green-conscious folk can get past the worry that pools aren’t a sustainable option and take advantage of some of the things they are good for: therapy, sheer enjoyment, or potable water in the event of a disaster.
Phillips of Questar Pools, who designs and builds pools internationally, urges people to consider the integration of the pool with the home to foster a connection between the two. “As we attempt as a society to get off the grid and make homes more efficient, we have to make sure all parts of our home are solar and not fossil fuel based.”
He also emphasizes the “vessel”—as he refers to pools—as a source of water to fight fires and for potable water for those who worry about disasters. “The only thing standing between hundreds of thousands of people and typhoid is chlorine,” he reminds. “Pools have survival benefits—20,000 gallons of treated water.”
His design premise is based on fire, food, and water. “You need to have these elements or people won’t go to the space,” he says, pointing out how restaurants use these concepts to get people to come into their venues and linger.
He believes design must embody lifestyle aspects.
As Phillips suggests, pools will become ever greener through technology adaptation and industry evolution, and their importance and use in coordination with the home will grow—making them far more than yesterday’s frolic space.
Photo courtesy Red Rock Pools & Spas
By the Numbers
Here’s an example provided by Dale Dennis of Home Energy Checkup on how a combined space heat, hot water, and pool heater system works out dollar-wise.
Sample system: Eight 4'x8' flat plate panels rated at 32,000 BTUs each
Sample list price: $32,000
Federal tax credit: $9,600
State/Utility: locate your state/local discounts at www.dsire.usa.org
Net price: $22,400 or less, when state/local discounts are considered.
Pricing and performance will be based on where you live, your homes current configuration, and heating load.
Sample system benefits:
- Generate approximately 730 CCF of gas or 21,535 kWh per year for the next 30+ years. The impact of this sun power can be greater than indicated above because your traditional fossil fuel equipment is far from 100% efficient, so you are getting less heat energy out than you are putting in. A solar thermal system loses very little energy converting the sun to heat (i.e., a small circulation pump and digital controller).
- Heat 70+% of your hot water needs for bathing, showers, etc. The remaining need will automatically be met by your existing water heater.
- Add a 10 degree pool temperature rise without fossil fuels. Additional heating needs can be automatically met by your existing pool heater.
- Heat your home by integrating with your existing heating equipment. The percent of heating load served depends on the efficiency of your homeís thermal envelope. A small, super-insulated home can have most of its heating needs met by the sun. A large or inefficient home may only have a small percentage of its heating load met.
- 30+ year system life
- 30% federal tax credit and in many cases state and utility rebates.
Au Naturale?
Your buyer can‘t handle chemicals? Try a natural pond.
Natural Pools have been in use in Europe for nearly 20 years. The pools are constructed like swimming pools but with a separate area—about 30% to 40% of the area of the pool—set aside for filtering the pools water. It is often designed to blend into the swimming area as a water garden. It can be attached with direct flow from the pool to the treatment area or can be detached with underground plumbing connecting the treatment basin. Water from the swimming area is circulated through plumbing with energy efficient pumps to the constructed wetland treatment area. Impurities that find their way into the water are nourishment for plants, beneficial bacteria, and microorganisms that in turn keep the water clean, clear, and safe for bathing.
Almost two decades worth of experience with public natural pools in Europe and German monitoring attest to the hygienic safety of biologically filtered natural pools. In fact, German public pools are rapidly converting to natural pools for the simple economic reason that they offer significant cost benefits over chemical water treatment pools.
For more information and to view natural pools, visit
Whole Water Systems or “
23 Breakthtaking Natural Swimming Pools”.
More Resources
Check out
DOE and the
Florida Solar Energy Center for more on solar pool heating. Visit
Alternate Energy Technologies and look at the photo at the bottom of the home page for attractive panel application.)