Dual Speed Pumps: Are They Really Worth It?

[mart242]

My pool builder is asking an extra 250$ if I want a dual speed pump instead of the single speed. At first I thought that it was a good idea to spend that extra money but now I'm not so sure:

Pump runs 8h / day, for 5 months (since I'll have a heater). That means 1200h of operation per year.

The pump is a 1hp hayward superpump that will operate on 240V. Consumption = 0.75kw...

1200h * 0.75kw = 900kW total.. a ~7c / kwh, that's roughly 63$ of electricity per year. If electricity shoots up to 10c / kwh (fixed rate is 7.5 for 5 years), it's still only 90$ of electricity. These prices are for Ontario, Canada.

If the pump is dual speed, I'll save ~60% of electricity if it operates on low speed... a savings of 50$ or so per year in the best case but the pump will still have to be ran on high speed a few hours per day I think (for proper chlorination).

Am I missing something?

[billp]

My pool builder is asking an extra 250$ if I want a dual speed pump instead of the single speed. At first I thought that it was a good idea to spend that extra money but now I'm not so sure:

... but the pump will still have to be ran on high speed a few hours per day I think (for proper chlorination).

Am I missing something?

As a rule of thumb you can run on low speed for 4 hours for the same cost as running on high speed for 1 hour. Since you pump roughly half as much water on low speed this means you save about 50% on low speed. In my area pool pumps are now costing people $.32 to $.35 per KWH so it pays off much faster than in your neighborhood.

I prefer to split the run time into morning and evening run times. Each has a high speed period that is long enough for the vacuum to clean the pool. That high speed time often doesn't need to be very long. There are many design features that affect all this.