Variable-speed pumps are not just a trend, they are a need

August 1, 2014

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One of the biggest advocates for the energy saving features of variable- or multi-speed pumps (VSPs) is Energy Star.®

By Scott Petty

As far as clichés go, ‘going green’ is a good one. But within consumer markets, the environmentally friendly frenzy is often overstated. Many so-called green products are often overpriced and/or ineffective. It is no wonder why many consumers have become jaded by the green movement. Escalating energy costs and social awareness are still forcing everyone to be more responsible, however.

There are nearly 1.2 million residential swimming [2]pools in Canada[3] and more than 10 million in the United States[4]. According to a 2012 report by the Consortium for Energy Efficiency [5](CEE), pool pumps installed in North America account for approximately 41 billion kWh of electricity annually. In fact, pumps account for approximately 70 per cent of the energy used to operate a swimming pool, consuming approximately 3500 kWh per year.

Figure_1[6]
Pool pumps are often the second largest contributor to home energy costs.

Taking this into consideration, and using Hydro Quebec’s 2013 annual comparison of electricity prices in major North American cities[7], with the average rate for electricity in Canada (at the time) being 19.63 cents/kWh and 13.79 cents/kWh in the United States, pools in Canada generate approximately $81.5 billion in energy costs per year, while south of the border these annual costs are roughly $241 billion.

Generally, pools can be expensive to operate. However, pool owners can turn to equipment manufacturers to help them reduce their costs and lower their carbon footprint. For those who own a swimming pool, pumps typically represent one of the most significant energy consuming devices in the home. In fact, they are often the second largest contributor to energy costs, only lagging behind the cost to heat/cool the home.

Single-speed pumps tend to waste more energy because they continuously operate (unnecessarily) at top speed; however, with the advent of variable speed pumps (VSPs), the movement towards energy efficient equipment is shifting.

Pool equipment manufacturers are striving to design and produce hard-working, efficient products that will allow homeowners to operate their pools more cost-effectively. This means more environmentally compliant equipment with proven performance that is built to last, while also lowering operating costs. It is generally agreed, the greatest potential for pool owners to save on operating costs is to switch their single-speed pumps to a two-speed, or better yet, a VSP.

The multi-speed movement

Multiple speed pumps are by far the fastest growing segment in the pool products market. This trend is definitely catching on and there are a number of reasons, including:

Education/communication

Media has played a big part in the increasing popularity of VSPs. When they were first introduced five or six years ago, the media helped educate the market on the potential energy and cost-saving benefits of VSPs.

Word of mouth was another strong factor in the driving force behind the importance of VSPs. Pool owners touted the energy and cost savings, which continued the momentum. Of course, the only thing that fuels a trend faster than word of mouth is social media. The popularity of VSPs was given a huge boost by online media platforms, such as Facebook, Twitter, Instagram, etc.

One of the biggest advocates for the energy saving features of VSPs is Energy Star.® This is a voluntary program designed by the U.S. Environmental Protection Agency (EPA), which is administered and promoted by Natural Resources Canada (NRCan), to help businesses and individuals throughout North America save money and protect the environment through superior energy efficient products.

Recognizing that a key component of swimming pools’ energy consumption is the pool pump—and noting many pool owners do not realize how much energy their pool pump may be wasting—Energy Star recently instituted a certified pool pump program[8].

This program recognizes the energy saved by pumps that run at variable speeds is considerable; reducing pump speed by one-half uses approximately one-eighth as much energy. On average, qualifying pumps use a third to two thirds the energy of standard models, depending on local climate, pump size, and number of speeds. The energy savings provided by these pumps can pay for themselves in two years. The EPA also states these pumps run quieter and prolong the life of the pool’s filtration system. Not surprisingly, the vast majority of Energy Star® qualified pumps are either variable- or multi-speed.

Legislation

Sometimes consumers do not have a choice. When governing bodies enact certain energy restrictions, manufacturers and consumers have to follow the law. These laws are ultimately less effective; however, the industry would probably still be using single-speed pumps had the ‘multiple-speed movement’ not started with the California Energy Commission’s (CEC’s) Title 20 and 24 Appliance Efficiency Regulations. This standard requires all new or replacement pool pump motors to meet certain energy efficiency standards (i.e. pool pumps must operate at two or more speeds).

Similar laws have been enacted in Arizona and Florida where swimming pool usage is particularly high. Beyond the government, industry associations and watchdogs help police compliance. For instance, the Pool & Hot Tub Council of Canada’s (PHTCC’s) Environmental Affairs Policy[9] and recommended guidelines for Energy Conservation Opportunities for Pools, Spas, and Water Features [10][G-0310] promote responsible environmental management best practices for the aquatics industry, while the Association of Pool & Spa Professionals (APSP), has released APSP-15 Energy Efficiency [11]Standard, which provides a database of compliant pumps.

Monetary motivation

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Variable-speed pump (VSP) versus single-speed pump.

It is always preferable to want to do something versus having to do it—either way money can be a great motivator. It is accepted that VSPs can save up to 90 per cent on energy costs compared to a single-speed pump. They match a pool’s needs versus a single-speed pump running at full power, 100 per cent of the time.As further validation, the EPA asserts Energy Star® certified pool pumps will usually:

The EPA notes in warmer climates where pools are used year-round, savings can be significantly higher.

Utility rebates

Beyond energy savings, there are other revenue resources available to pool owners. For example, a number of utility companies may offer rebate incentives to pool owners to encourage the purchase of energy-efficient swimming pool pumps. Taking into consideration the number of utilities across North America that offer some type of rebate—in addition to manufacturer rebates—this can be a significant external influence.

Technological advancements

VSPs can be likened to HDTVs. Once consumers can see the advancements over the previous technology, there is simply no going back.

Further, many compare the single-speed pump to a light switch—it is either on or off. A VSP is more like a dimmer switch, allowing the pump to be dialed to whatever speed is necessary and operating only when it is required.

In addition to tremendous energy savings, operating pumps at lower intervals have multiple benefits, including:

Technological advancements in calculating energy savings is another factor in the increasing popularity of VSPs. There are many apps and online calculators that can help customize the energy savings to the individual. In fact, many manufacturers have virtual user interfaces for each of its VSP models.

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Some systems even allow users to simulate pump operation on the control panel, allowing them to adjust the pump to different speeds by simply sliding the app buttons to view actual savings when operating the pump at different speeds.

After entering the place of residence, pool professionals and homeowners alike can use these energy-saving calculators and/or apps to estimate the parameters that the user can adjust to their specific situation. These options include: horsepower of current pump; average daily run time of pool; rate currently paid for electricity (in dollars per kWh); pool size (in litres/gallons); and the approximate length of the pool season.

Using this information, the app will demonstrate how much can be saved in energy costs by switching to a VSP in conjunction with other energy-saving equipment. Some systems even allow users to simulate pump operation on the control panel, allowing them to adjust the pump to different speeds by simply sliding the app buttons to view actual savings when operating the pump at different speeds. This further helps users appreciate the energy savings potential when running pumps at lower speeds.

Ultimately, manufacturers are hoping to raise pool owner’s and operator’s awareness of what is possible in terms of energy and cost savings.

The pump affinity law

Another law that has nothing to do with legislation is the ‘pump affinity law,’ which deals with the relationship between motor speed, flow rates, and energy consumption. This law states that power consumption drops at a nonlinear rate as pump speed is reduced. By cutting the motor speed in half, the flow rate is also reduced to half, but the power consumption of the pool pump is reduced to approximately one-eighth of the original draw. Proper time and speed settings will ensure energy savings are the highest possible.

Pump Affinity Law
Operating the pump at half speed:
• reduces the flow rate to approximately half;
• slower moving water reduces the amount of resistance in the hydraulic system (total dynamic head [TDH]) in feet by one-quarter;
• uses approximately one-eighth the power (approximately); and
• uses one-quarter the energy (75 per cent savings) at the same turnover (twice the run time). Greater savings are possible if operated at less than half speed.

Product proliferation

As noted earlier, VSPs are the fastest growing segment within the pool product market. With more choices than ever before, consumers are finding the multiple-speed pump that best serves their needs.

VSPs were first introduced almost a decade ago. Since then, most pool manufacturers have launched full model lines. While the majority of pool pumps on the market today remain single speed, multiple-speed pumps are catching up quickly.

What is holding the industry back?

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A variable speed pump (VSP) is like a dimmer switch, allowing the pump to be dialed to whatever speed is necessary.

While the trend is going strong, there is still some resistance to VSPs. Pool owners are often slower to upgrade their equipment to more energy saving technologies than they are in other areas of their lives (e.g. smartphones and TVs), perhaps because they do not regularly interface directly with their equipment.

Another reason why many pool owners are not looking for the greenest, most advanced equipment technology can be attributed to a simple matter of habit. Single-speed pumps have been tried-and-true for more than 40 years, this alone has made it difficult to convince people to switch to newer technology. Further, the upfront cost of converting to a VSP may also deter some pool owners. Prior to having the hard data to show consumers the realized energy and cost savings, which would offset the expense of a VSP, many were simply unwilling to spend the money. Energy savings were largely masked in the past as most could not answer the pool owner’s question about how much their pump costs them. But this is all changing.

Now, there is documented data showing the significant savings a pool owner can realize by switching to a VSP.

According to the U.S. Department of Energy, the following example illustrates how replacing a single-speed pump with a VSP can create significant energy savings. The average residential swimming pool contains 94635 L (25000 gal) of water and has a suggested turnover rate of 24 hours. A single-speed pump drawing 2,000 watts, operating at 3450 r.p.m. and generating a flow rate of 250 litres per minute (lpm) (66 gallons per minute [gpm]) can turn over the entire volume of water in roughly 6.3 hours.

(94635 L [25000 gal] / 250 lpm [66 gpm] / 60 minutes per hour = 6.3 hours)

At this rate the single-speed pump would consume 12,600 watt hours (12.6 kWh) per day to turn over the pool.

(6.3 hours x 2000 watts = 12600 watt hours [12.6 kWh])

However, because of the pump affinity law, slower flow rates create greater energy savings. In the field, a VSP set at 1150 r.p.m. would generate a flow rate of 83 lpm (22 gpm) and draw approximately 116 watts. This would turn the pool over in 19 hours but only consume 2.2 kWh of electricity.

(94635 L [25000 gal] / 83 lpm [22 gpm] / 60 minutes per hour = 19 hours)

(19 hours x 116 watts = 2200 watt hours (2.2 kWh)

This math cannot be argued. While there may have been some reluctance to make the conversion in the past, the phrase popularized by Star Trek comes to mind: “Resistance is futile.”

VSPs: From trend to necessity

Going green is so much more than a trend or, worse, a fad. The movement to make pools more energy-efficient will potentially save consumers millions of dollars in energy costs. It is also a huge boon to the trade as it represents millions in technology upgrades in Canada and the United States. This is a tremendous (even daunting) opportunity for the entire pool and spa industry.

It is not an overstatement to say the greatest potential for pool owners to save on operating costs is to switch their single-speed pump to a two or, better yet, VSP. In making the switch, consumers can not only save money, but also do their part to help the planet.

 

Petty_HeadshotScott Petty is the global product manager for pumps and above-ground equipment for Hayward Pool Products. Previously, he managed Hayward’s test facilities and agency compliance activities. Over the course of 10 years in the pool industry, Petty has cultivated an expertise in energy efficiency and hydraulics. He has a bachelor of science in mechanical engineering from North Carolina State University and a MBA from Wake Forest University. He can be reached via e-mail at spetty@haywardnet.com[15].

 

Endnotes:
  1. [Image]: http://psm.poolspas.ca/wp-content/uploads/2014/08/5.jpg
  2. residential swimming : http://oee.nrcan.gc.ca/corporate/statistics/neud/dpa/data_e/sheu03/publication_en_038_1.cfm?attr=0.
  3. Canada: http://www.kenilworth.com/publications/psm/de/201404/files/8.html
  4. United States: http://www.energy.ca.gov/appliances/2013rulemaking/documents/responses/Residential_Pool_Pumps_and_Replacement_Motors_12-AAER-
  5. Consortium for Energy Efficiency : http://library.cee1.org/sites/default/files/library/9986/cee_res_swimmingpoolinitiative_07dec2012_pdf_10557.pdf
  6. [Image]: http://www.poolspas.ca/wp-content/uploads/2015/04/Figure_1.gif
  7. North American cities: http://www.hydroquebec.com/publications/en/comparison_prices/pdf/comp_2013_en.pdf
  8. certified pool pump program: http://www.nrcan.gc.ca/energy/products/categories/appliances/pool-pump/14005
  9. Environmental Affairs Policy: http://www.poolcouncil.ca/news/news_item_122.pdf
  10. Energy Conservation Opportunities for Pools, Spas, and Water Features : http://www.poolcouncil.ca/pdf/publications/EnergyGuidelinesEng-G0310.pdf
  11. APSP-15 Energy Efficiency : http://apsp.org/resources/energy-efficient-pool-pumps/apsp-15-compliance.aspx
  12. [Image]: http://www.poolspas.ca/wp-content/uploads/2015/04/Figure_2.jpg
  13. [Image]: http://www.poolspas.ca/wp-content/uploads/2015/04/Figure_3.jpg
  14. [Image]: http://www.poolspas.ca/wp-content/uploads/2015/04/1.jpg
  15. spetty@haywardnet.com: mailto:spetty@haywardnet.com

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