WHAT PUMP SIZE IS BEST
The best pump size is THE one that costs the least to operate
The cost to operate your pool is a reoccurring monthly cost that can really add up over a year and more over the lifetime of the pool.
pump Selection - Skimming
You want a pump that will provide enough water to operate your skimmer to collect the leaves and surface debris. This is 15 gpm to 35 gpm.
pump selection - backwashing
Your pump should be able to provide enough water flow to backwash the filter. For a sand filter, this is 20 gpm/sq. ft. of media.
Single speed pump
A single speed pump was the typical pump used 20 years ago. They come in various sizes and mounting flange type. Even a 1/2 HP can draw 6.5 amps. at 120 vac. This calculates to 780 w/hr. used.
two speed pump
The two speed pump was the successor to the single speed pump. It offer a low speed (low flow) for daily filtration and a higher speed (high flow) for backwashing. The electrical requirements for a 1 1/2/.3 HP pump are typically 1.5 amps on low and 11 amps on high speed. This calculates to 180 w/hr. Since the flow is reduced by 50 at this lower speed, you must run the pump twice as long resulting in 360 w/hr. As you can see, this is still more than a 50 % reduction in electricity moving the same amount of water. (2 x 180=360)w/780w=0.46%.
Two speed pumps are a logical and worthwhile consideration for above ground pools. The smallest two speed is a usually a 1 HP/,25 HP. Analyze the pump curve for the lower speed.
variable speed pump
The industry standard for in-ground pools is now the variable speed. The flow can be adjusted to match the desired flow. The desired flows are between 15 gpm and 35 gpm. At these flows, the pump speed is usually below the (low speed of a two speed pump) resulting in even greater savings. Typical savings can be 75% to 85% less than a single speed. With a properly sized filter, piping and pump, pumping 30 gpm can be accomplished using only 100 watts/hour of electricity.
FEDERAL DOE STANDARD SEPTEMBER 2025
Starting on September 29, 2025, manufacturers will only be selling variable speed pumps. Existing inventory at distribution, retail and contractors may still be sold. Once they run out, the consumer will only be able to purchase the more expensive variable speed pumps. There is one allowance for pumps less than 1/2THP but at this point, no motor manufacturers are producing this motor for pump manufacturers. There are other types of pumps but none of them have a pump pot or strainer.
This includes all the packaged pool pump/filter combinations.
VARIABLE SPEED PUMP
Waterway
Waterway
Waterway
Mustang VS 140
Variable Speed. 1.4HP 2" piping
Waterway
Waterway
Waterway
Power Defender 165
Variable Speed 1.65HP 2" piping
Pentair
Waterway
Pump flow
SuperfloVS
Variable Speed 1.65HP 2" piping
Pump flow
Pump flow
Pump flow
Baseline pool water flow was determined to be 32 gpm using a standard skimmer with a 1-1/2" outlet port.
A typical pool system using a properly sized sand filter, standard piping runs of 20 feet in one direction and having two returns results in approximately 10 - 20 feet of head resistance. Using the above pump curve, the expected pump speed is 1320 rpm.
Pump flow
Pump flow
Pump flow
Baseline pool water flow was determined to be 32 gpm using a standard skimmer with a 1-1/2" outlet port.
A typical pool system using a properly sized sand filter, standard piping runs of 20 feet in one direction and having two returns results in approximately 10 - 20 feet of head resistance. Using the above pump curve, the expected pump speed is below 1600 rpm.
Pump flow
Pump flow
Pump flow
Baseline pool water flow was determined to be 32 gpm using a standard skimmer with a 1-1/2" outlet port.
A typical pool system using a properly sized sand filter, standard piping runs of 20 feet in one direction and having two returns results in approximately 10 - 20 feet of head resistance. Using the above pump curve, the expected pump speed is below 1800 rpm.
TWO SPEED PUMPS - AVAILABLE UNTIL SEPTEMBER 29, 2025
Waterway
Hi-Flo pump curve
Hi-Flo pump curve
Waterway High Flo and High Flo II
TWO speed pumps.
Hi-Flo pump curve
Hi-Flo pump curve
Hi-Flo pump curve
Hayward
Hi-Flo pump curve
Hayward
SP15922S
No flow curves were found on the internet.