There’s nothing ambiguous about saving energy. Whether out of concern for the environment or simply a desire to save money (or both), reducing energy consumption is always a good idea.
When it comes to pools and spas, they can go either way. Poorly constructed and improperly equipped man-made bodies of water can squander tremendous amounts of energy both in heating and electricity, sometimes causing great frustration for owners when it comes time to pay the monthly electric and/or gas bill.
By contrast, when designed and installed with energy conservation in mind, pools and spas can be run at surprisingly reduced costs. In working with homeowners and commercial pool operators, the industry has a compelling and multi-pronged story to tell about how turning to efficient technology and design can significantly reduce operating costs. Solar heating, heat pumps, pool covers, variable-speed drive pumps, efficient hydraulic design — the industry boasts a robust set of energy efficiency options.
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And those options have for many years been codified in standards and guidelines for pool design and installation that have focused largely on energy efficiency. Documents such as the APSP/ANSI/ICC-15 standard for energy efficient swimming pool design, California’s CEC Title 20 and 24 codes, and Arizona’s Title 44 have given pool builders, service techs and building inspectors guidance on how to reduce consumption for both pumping and heating water.
GOV’T ASSISTS
On the federal level, the Energy Star program has also dramatically advanced the promotion and use of efficient components by way of cataloging pumps and other products deemed “efficient.” The program also offers basic guidance and data that shows just how much can be saved by smart component selection, installation and operating routines.
And savings can be dramatic depending on a range of variables. In a study published by the DOE and conducted by the Center for Energy Conservation at Florida Atlantic University, a sample of 120 pool owers saved as much as 75 percent on their electric bills by using some basic measures, all of which should be familiar to many builders and service techs. Increasing pipe and filter size, downsizing the pump or using a variable-speed drive pump, reducing hours the water is circulated or running the system at an extremely low speed a majority of the day — all contribute to increased efficiency, longer service life for pumps and motors and even improved water quality.
In addition, the U.S, Congress recently passed the Bipartisan Budget Act of 2018, which reinstated tax credits for a variety of energy-efficient technologies including wind, solar and geothermal technologies.
Naturally there are many factors that can influence energy savings, including climate, regional energy prices, the desired water temperature and the complexity of the pool or spa system itself. Systems that include multiple features such as vanishing edges, waterfalls and in-floor cleaning systems can realize greater saving because they require more power to operate, but all systems, from the simplest aboveground pool to multifaceted aquatic facilities, can benefit from common sense efficiency measures.
EFFICIENT OPTIONS
Sunlight:
Using the great bounty of free energy from the sun has long been one of the most surefire ways to affordably heat water. According to some manufacturers, solar heating systems have experienced a modest resurgence in recent years as their return on investment has been bolstered by improved efficiency in materials and product design. For example, Fafco’s CoolPV system, which combines solar water heating with photovoltaic power generation, has given solar new life for customers looking to both affordably heat their pools and generate electricity.
These days, estimating cost savings is easy for consumers and professionals with calculator apps. As an example, a solar heating calculator from Energy Star indicates that in some circumstances, a solar water heating system can conserve up to 50 percent of the energy needed to heat a pool.
The solar industry has been further bolstered by tax credits and rebates. The tax credit mentioned above is currently 30 percent of the cost (including installation costs), with no upper limit. (The credit decreases to 26 percent for tax year 2020 and drops to 22 percent for tax year 2021.)
Covering Up:
Solid pool covers are among of the most effective means of conserving energy because evaporation is responsible for most energy loss in pool and spa systems.
Evaporating water requires tremendous amounts of energy. According to the DOE, it only takes one Btu (British thermal unit) to raise one pound of water one degree, but each pound of 80-degree water that evaporates removes 1,048 Btu of heat out of the pool. That’s why covering a pool when it’s not in use is often cited as the single most effective means of reducing pool heating costs, with possible savings of 50 to 70 percent.
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Those impressive energy and conservation numbers have been the basis for the automatic cover industry’s efforts to gain certification in the U.S. EPA’s WaterSense program, which is similar in many respects to Energy Star.
Variable-Speed Power:
The advent of variable-speed drive pumps in the early 2000s revolutionized pump technology. Manufacturers claim possible savings as high as 85 percent, especially in systems with multiple operating scenarios. As is true of solar heating, manufacturers of VSD pumps offer energy saving calculators to give homeowners an easy way to estimate savings. And regulations such as those cited above in California and Arizona mandate the use of either VSD pumps or multi-speed pumps for new vessels and pump replacements.
Pumping Btu:
Heat pumps are more expensive than fossil fuel heaters, but they are also more efficient. Heat pumps run on electricity and use refrigerant to absorb heat from the air, water or ground rather than generating heat from a fuel source. Manufacturers tout the fact that with proper sizing, installation and maintenance, heat pumps can last longer than gas pool heaters, resulting in greater long-term savings.
Heat pumps are sized based on the pool’s surface area and the average difference between the desired water temperature and air temperatures. Wind, humidity and daily average temperature fluctuations also come into play. They are rated by both Btu output and horsepower. In some cases, heat pumps can be combined with geothermal heating systems to generate even greater efficiency.
Gassing Up:
Finally, traditional fossil fuel heaters remain a mainstay for pool and spa heating. All major manufacturers sell high-efficiency models that offer significant savings over many older models. Some newer models boast efficiency ratings in the 89 to 95 percent range.
Comments or thoughts on this article? Please email Eric at [email protected]
