As operating expenses continue to rise and annual budgets shrink, finding ways to trim energy costs is even more important today than it was 10 years ago, when variable-speed pumps first came on the pool scene.

Every year, facility managers sit down to review their operating expenses, and one huge figure never seems to shrink — the electricity cost.

Everyone realizes that the pump room is one of the largest consumers of electricity in an aquatics facility, so it’s a logical place to start. Luckily, several new “cost calculators” are available that allow operators to determine exactly where that power is being used. Many professionals use the figures generated from cost calculators to reinforce their requests to upgrade to more efficient equipment or add variable-frequency drives. They also can be used to help a facility qualify for rebates from the local utility in exchange for using energy-efficient products or VFDs. Learning the potential savings from equipment upgrades is the first step in renovating a pump room. When an aquatics facility sees on paper that it can save from $300 to $1,000 a year in electricity costs or, in some cases more, it becomes much easier to justify an upgrade.

What is the cost calculator?

As the name implies, these programs determine the cost to power one particular piece of equipment. Pumps are a great place to start because they are big electricity users.

With this data, cost calculators identify power demand and energy use per day and, more importantly, the cost each year. Comparing the usage figures of current equipment to those of new, energy-efficient pumps puts the savings in black and white.

The use of these cost calculators is quite simple. Once you have all the information required, it’s just a matter of entering it in.

The calculator will begin by asking questions about the aquatics facility, such as how many gallons of water are in the pool and the pump's turnover time.

Calculators also ask if there is a minimum required flow rate, the number of days the facility is open each year, and how many hours it operates daily. Be sure to have an electric bill handy to enter the cost per kWh of electricity and the horsepower of the existing pump. Many people do not know the cost per kilowatt hour, but this is a key figure. It can be located on a utility bill or by calling the power company.

Calculators will even take into consideration the suction and return pipe size and estimated flow rate.

It is important when looking at these cost calculators to remember one thing — turnover rate. If your local health department requires the minimum flow rate needed to achieve a six-hour turnover 24 hours a day, then remember there’s still potential for savings by using a VFD to clean the power going to the pump, which could result in at least a 5- to 10 percent savings.

Also consider this: If you run the pump at higher flows than needed during operating hours, there could be a case for slowing it down during nonoperating hours. This could maintain the turnover rate while still resulting in energy savings for part of the day.

How does the cost calculator compute?

Cost calculators have pre-loaded formulas to make it easier and faster for aquatics professionals to obtain the data they need. Ultimately, the calculator shows how reducing pump speed saves energy by a cube factor. The computation takes kilowatt hours (measuring energy used) and rpm (which measures speed) to determine the savings.

The calculators also have integrated pump affinity laws into the computation. This allows an aquatics professional to demonstrate that lower pump speeds save energy by a cube factor.

Because of the affinity law, reductions in energy consumption have a larger impact than most people realize. It doesn’t work the same as in other examples. Reducing the speed of a pump by 20 percent automatically results in a flow reduction of 20 percent.

However, energy consumption is reduced by a cube factor! So a 20 percent reduction in flow provides almost a full 50 percent reduction in energy. Even a 10 percent reduction of flow saves more than 25 percent of energy!

Commercial aquatics facilities and utilities

The electrical grid is stressed. With an aging infrastructure and constrained capacity, utility providers are seeking rapid reductions in the amount of power they must provide. More than 322,000 aquatics facilities pumping 70 billion gallons of water make for a nice target. The aquatics industry could make a huge impact on electrical demands. If every pool saw a 20 percent reduction in pump speed for one hour a day, it would free up four medium-sized power plants. A 50 percent reduction for one hour would spare seven medium power plants.

CPS Energy, in San Antonio, Texas, is an example of a utility looking for quick reductions in power usage. The Lone Star State is among those with the most commercial pools in the nation, with well over 30,000 installed pools as of 2012. The city of San Antonio worked with CPS Energy to reduce the city’s energy usage. An initial energy audit of the city, using tools similar to those of a typical cost calculator, showed that retrofitting 22 city-owned pools would result in a dramatic reduction in energy demand that would pay the needed renovation in less than one year! The city replaced older pumps and installed variable-frequency drives. The total project cost, including equipment and labor, was $137,000. However the annual electrical savings was $63,000 and CPS gave the city of San Antonio a rebate of $87,000. This gave the city a payback on the project of just nine months and a five-year return on investment of 530 percent.

Using the cost calculator for proposals

For pool professionals working with aquatics facilities, using a cost calculator is the first step in convincing operators to consider upgrades to their pump rooms.

Operators can download results onto company letterhead to make their presentations even more professional. It’s always good to have it ahead of time on paper so you can show it to clients or officials. For even more impact, you can show them during a meeting with the calculators right there online in front of them so they can see the potential savings being calculated.

It’s an easy tool to close a deal with a facility that might be hesitant to upgrade equipment. By showing them on paper, you can open their eyes as to how much will be saved. When you can go from a $1,000 power bill to $300 in one year after upgrades, it’s a real no-brainer. Then the question becomes, what will the facility do with that extra money?

Remember, it’s best to present the information from the cost calculator as an estimated savings potential. Anything can happen in real time, but what you’re doing is using proven formulas and data to show the effects of bringing these pumps where they need to be instead of using one that’s pumping more water and using more energy than is truly needed.


When you’re looking for money to put into that new program at your facility and are not sure where to get it, remember to start at the heart of your pool — the equipment room. Whether it’s an old pump or motor that needs to be replaced, or the many lights you find in a pool, spa or waterfeature, there are annual savings to be obtained. These new energy-saving products generally last much longer than standard products that have been in place.

Ask yourself a popular question when considering the change to energy-efficient products: “What’s the cost of doing nothing?” Think of that answer while using cost calculators to estimate the tremendous savings potential for aquatics facilities

Fowler is the commercial marketing and sales manager at Pentair Aquatic Systems in Sanford, N.C. In his 24 years with the manufacturer, he has held posts in the technical services department along with managerial roles in various departments, including marketing, accounting and products.