Let’s take a look at the options, get to the bottom of the pump speed debate, and find out if a variable speed pump makes sense for you!
1) Single Speed Pumps
A single speed pump is a one trick pony. Simply feed it electricity (quite a lot of it!), and it will go full speed ahead, generally at 3450 RPM (revolutions per minute). Because there is no throttling in a single speed pump, they are known to be noisy and inefficient.
The one positive? Single speed pumps are by far the cheapest initial investment.
2) Dual Speed Pumps
A dual speed pump features the same basic induction motor as a single speed, but with an extra trick up it’s sleeve. In addition to running at a full 3450 RPM, a dual speed pump is capable of halving it’s internal speed to 1725 RPM. This makes for much quieter, efficient operation. The full 3450 RPM speed is there when you need it (when vacuuming your pool, for example), but for the most part a dual speed can handle it’s job at 1725 RPM just fine.
It should be noted that the switch between speeds is manual; you (the pool operator) must make the change.
3) Variable Speed Pumps
Unlike dual and single speed pumps which utilize standard induction motors, the motor in a variable speed pump is a different sort of beast: they feature what is known as a “permanent magnet motor”. Without breaking out the protractor and getting into advanced engineering topics, a permanent magnet motor can be defined in a word: efficient. A variable speed pump can fluctuate RPM across a very wide range as need arises.
As an example, a Hayward EcoStar is able to operate in a range of 600-3450 RPM. Not only can you alter pump speed based on your pool demand, but you can schedule your pump to operate during off-peak hours when electricity is cheapest. Check with your power company to determine your pricing schedule!
What Type of Pump Should You Buy?
If you can afford the initial investment, go variable speed! Ignoring the upfront costs, there is no practical reason not to. The icing on the cake? They are so much more efficient that they generally pay for themselves within 1 to 2 years. Most manufacturers throw around terms like “90% more efficient”, and it’s not just marketing speak. Comparing 600 RPM to 3450 RPM, it’s just common sense!
If a variable speed doesn’t make financial sense for you in the short term, an efficient dual speed is no slouch either. Under no circumstance, however, do we recommend a single speed pump for general swimming pool turnover usage.
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