Two Speed Vs. Variable Speed Pool Pumps

By March 14, 2015 Informative No Comments
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Single Speed Pump

Single speed pool pumps have been around for over 50 years in the pool industry and have come a long way because of the pump itself mostly but also because of the motor too. The “wet end” of the pump has changed over the years to move a considerable amount more water with closed faced impellers and diffusers instead of open faced impellers only. This change gave you about a 40% increase in gallons per minute from the same horsepower motor. The motor itself is more energy efficient using better technology with more copper winding’s saving about 20% more energy. The average pool pump (1 Hp.) pulls about 6.5 amps and moves about 60 gallons per minute. If you do the math and you are paying .18 per kilowatt hour to your electric company and have a 20,000 gallon pool, you will spend about $1.56 per day or around $46.70 per month to run that pump.

Two Speed Pump

Two speed pumps have been around for about 15 years now and have now lost their market-share to the new variable speed pumps, and for good reason. They were created to give pool owners a way to run their pumps in a lower speed most of the time and then increase the speed for just a couple of hours each day to run other water features that need more water flow like a pool cleaner. The idea was that you would save money each month by not always running the pump in a high speed. The problem with this system was that you still want to run all of the pool water through the pool filter one time per day. That means 10 hours in low speed plus 2 hours in high. That would be fine if the amp draw in low speed was super low but it is not. The average two speed pump running in low speed still pulls about 3.5 amps but only moves around 20 gallons per minute. When it is in high speed it pulls around 6.5 amps and moves around 60 gallons per minute. If you try to only use the high speed to run your pool cleaner two hours per day and still move the needed 20,000 gallons of water you would spend about $2.17 per day or around $65.10 per month to run this pump.

Variable Speed Pump

Variable speed pumps still use the same “wet end” of the pump that a single and two speed pumps use but it has a totally different motor. The motor for a variable speed pump is not a traditional copper winding motor. They use a permanent magnet motor that runs very quite and has little vibration which lengthens the life of the motor and saves energy. Calculating the cost to run this pump compared to a single speed pump is difficult because of all of the variables involved. The cost savings according to most of the manufacturers can be as high as 90% over a single speed pump. I think that would be the most extreme example and not found unless the single speed pump was running way too many hours to move the 20,000 gallons in this example. For comparison purposes I will calculate the pump pulling about 1000 watts and running the number of hours to move the 20,000 gallons. I will use a 1 horse power single speed pump as above to move the same gallons of pool water. The variable speed pump will need to run about 6.67 hours and cost about $1.20 per day or about $36.02 per month.
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