Costs of Running a Pool Pump

What's it cost to run a pool pump? How much of your hard earned cash goes to paying for the pump to run? These are the questions we hope to answer in today's post. Specifically, how can you calculate the energy cost of running your pool pump? Is there an average energy use for pool pumps? And finally, what steps can be taken to reduce pump energy use and reduce the cost?

How Much Does it Cost to Run a Pool Pump?

Figuring out the cost to run a pool pump is fairly easily. On the pump label shown here (yours may look slightly different), you will find Volts and Amps listed. In this case, it shows volts as 115/230V which means that the motor is 'reversible' and can be operated at either 115V or 230V. The Amps are listed as 15.0 / 7.5 - which means that at 115V the motor draws 15A, and at 230V the draw is 7.5 Amps. For a larger motor over 2hp, you will commonly see only 230V listed and a single number to represent Amps used at maximum load.

Note that the pump label or 'name plate' shows the Maximum Amp Draw. Many pool pumps after start-up, will pull 1-2 less amps than listed on the nameplate. They can also draw more amps than listed too, if it is too large for the system and plumbing, or there is a low-voltage problem.

The next steps involve some math:

1. Multiply: Volts X Amps = Watts. In our particular example, assuming 230 volts, 230V x 7.5A = 1725 Watts
2. Divide: Watts / 1000 = KiloWatts (Kw). In our example, 1725 / 1000 = 1.725 Kw
3. Multiply: Kw X Hours per day of running the pump. For example, 1.725 Kw X 10 hours = 17.25 kWh per day
4. Multiply: kWh/day X Cost per Kilowatt. For example 17.25 kWh X .12 cents/kWh* = $2.07 per day

*Your cost per kWh may be higher than the national average of 12 cents, some areas of expensive electricity pay double this amount, per kilowatt hour. Check your electrical bill / statement, or login to your 'paper-free' provider account online, to find out what your exact rate or fee is, per kilowatt hour (kWh).

How Much Energy Do Pool Pumps Use?

It depends on how big your pump is, and how energy efficient it is. Larger horsepower pumps draw more amperage (which is what you really pay for), and thus more Kilowatt hours (kWh). Energy efficient (EE) motors are less amp hungry than standard pump motors. Our 1 hp (standard) example UST1102 motor above will cost between $1-$5 per day, depending on what your power company charges per kWh, and on how many hours per day the pump is running, which changes within the season. This will result in a monthly cost of $30-$150.

A 2 hp pump won't pull twice as many amps as our 1 hp example motor UST1102, but it will be more, about 25% more, up to 20/10 amps. The EE version of our example motor, the UCT1102 'The Conservationist', uses 11 / 5.5 max load amps, or a reduction of just over 25%.

Our 1 hp example pump uses 1.75 Kw per hour; whereas a 2 hp motor of the same type (UST1202) would draw 2.4 Kw per hour. That's around 24 kWh per day, or around 720 kWh per month, just running only 10 hors per day. During the heat of the summer, many pumps need to run longer to maintain clear water. And remember, pool pumps never get to take a day off.

Do 230V Pool Pumps Use Less Energy than 115V Pumps?

A 230V pump draws less amps than does a 115V (plug-in) pump - exactly half, but when you multiply it by twice the voltage, the Watts result is the same. For instance, returning to our example 1 hp motor and math calculations above, we deduced that 230V x 7.5A = 1725W, where Volts X Amps = Watts. Using 115V instead, the calculation looks like this: 115V x 15A = 1725W, or exactly the same.

So, No - wiring up a pump with 230V instead of 115V will not reduce amperage draw (wattage consumed), or save money on your electrical bill. However, since each leg (wire) supplying power to pump is carrying only half (50%) of the amperage, there is less 'line loss' per line, or amperage that is lost. The savings in line loss is slight, but may be meaningful over the long term.

Does your pool pump use 115V or 230V?

Most above ground pool pumps use 115V, and most inground pumps use 230V; but it can be different. If your pump plugs into an 3 prong outlet, chances are it's 115V. Your motor label will tell you if your pump is 115V, 115V/230V or 230V. Now, if it says 115V/230V, it could be wired up either way, although it comes from the factory wired 230V, and most inground pools are wired with 230V. But if you want to be sure, you can look at the breaker box for the pump, usually a sub-panel or smaller 100amp breaker box, the usual gray color, near the pump. A double pole breaker is 230V, with two hot wires connected to it. Double pole breakers are about 1.5" tall. Single pole breakers (115V) only have a connection for one wire, and are much thinner, about 3/4in tall.

Another way; for those with a timeclock, the voltage may be listed inside on the label. Finally, a voltmeter can be used to test the power wires coming into the timeclock. Another way is to match the voltage diagram on your motor label, to how the wiring is connected on the terminal board, in the back where the wires connect. A pump labeled 115V/230V will come factory wired for 230V (high voltage) but can be switched to 115V (low voltage).Or your pump may be labeled just 115V or 230V, in which case it cannot be the other.

Ways to Reduce the Cost to Run a Pool Pump?

Here's a bunch of ways to reduce the cost to run a pool pump. Some are more useful than others, or feasible for your case.

Reduce plumbing & equipment restrictions: 

The pool pump has to overcome vacuum and pressure restrictions, and attempts to balance or straddle these two forces, at a point between the pump curve and system curve. Or said more plainly, the resistance that the pump must overcome is in proportion to the amount of Work the motor has to do. 2 inch plumbing is used on larger pumps, because the larger diameter has less resistance than 1.5 inch pipe. Larger pool filters are also less restrictive than smaller filters and run with lower filter pressure. Check valves, directional valves, chlorinators or purifiers all add restriction, as does a pool heater.

Finally, the fewer bends in the pipes, to and from the pool, the better. Every bend or turn in the pipe adds resistance to the system. Total Resistance, as seen in a pump curve shown to the right, is a measure of all of the pipe, fittings, and other equipment (filter, heater, chlorinator, valves) resistance. Most pools are in the 20-40 ft of head, but some systems can run higher. Put even more plainly, if the plumbing pipe size can be increased, or redesigned for fewer bends and twists, and if unnecessary equipment is removed, or if the filter size is increased - these will reduce the Work for your pump motor, which will then need fewer amps, to get the work done.

Invest in a variable speed pump:

Variable speed pumps use lower speeds to consume less energy. When you reduce impeller speed (RPM) by half, you reduce the amperage required by 8 times! Basic models like the Superpump VS or Max-Flo VS have several speed options, which are pre-set. Full-featured VS pumps like the IntelliFlo or EcoStar are able to sense the required pressures and achieve a balanced harmony with the perfect impeller speed to get the job done.

Variable speed pool pumps can reduce energy consumption by 50-80%, so payback on their higher purchase price comes within a few years. VS pumps have another attractive quality in that their motors are quiet and cool permanent magnet motors, which last longer than traditional induction motors.

Install an energy-efficient motor: 

Most pumps that you buy online, or installed by a builder are using 'Standard' motors. But if you were to swap out a dying motor with the Energy Efficient (EE) or High Efficiency (HE) equivalent motor, you could reduce amp draw by 25%. This is done by using improved design concepts and materials that result in lower electrical loss.

Install a smaller horsepower pump: 

A lot of people don't know this, but not all 1 hp pool pumps produce the same amount of flow and pressure. There are medium flow, high flow and very high flow pumps. A 3/4 hp Whisperflo pump produces about the same flow rate as a 1.5 hp Superpump. Or a 1 hp Challenger pump can produce the same flow as a 2 hp Super Flo pump. A smaller pump horsepower translates to lower energy costs, because they use fewer amps. Replacing a medium-flow high-hp pump with a high-flow low-hp pump is what I'm talking about.

Invest in a larger filter: 

And/or a more effective filter. A pool filter that is more effective (like a DE filter) is so efficient at trapping dirt that less filter pump run time is possible. And a bigger filter is also going to have greater dirt trapping ability, but perhaps more importantly will have less resistance than a smaller filter. Running at lower pressure, the larger filter is less Work for the pump to push water through.

Install a side valve: 

If you have a choice in the matter, for sand and DE filters with side mount valves, the Slide valve, aka Push-Pull valve has less resistance than a multiport style valve, especially in the 2 inch size. Cartridge filters, on the other hand, have no filter valve at all, and also can be a way to reduce filter resistance and motor work.

Keep your pool water balanced: 

Proper water balance and sanitization practices reduce the need for additional filtration.