OK, it’s time for me to replace my single speed 1hp Hayward pump. I get how the variable speed saves energy ($) because it runs at a slower speed. BUT, my question is, why not get a pump motor that runs at a single slower speed to begin with? From all I’ve read, everyone just runs their variable speed motors at one slower speed all the time. A single speed motor, running at a slower speed, should produce the same savings and would cost a lot less up front compared to the variable speeds.
It might not be strong enough to run pool features or a pool cleaner and would take longer to filter all the water. I am repairing my old 1 HP single speed pump before I spend $1000+ on a variable. I wonder if it wouldn’t be cheaper to install two single speed pumps, one smaller and one larger than spend what they want on a variable speed. They sound like they are a pain to use. (I have trouble setting my sprinkler timer.) Also be aware that if you install a variable speed yourself, you won’t get much of a warranty from the manufacturer (60 days). And the savings will only occur during the summer months. Here in AZ, I can get by only running my pool pump a few hours in winter, and I am on a time-of-use plan where cost is $.0721/kwh hour, ends up to be about $9/month running a single speed 1 HP motor. I figured I’d only save money for 3-4 months out of the year. After installation (talked with several pros) and mark up on the new variable speed pump I’ve gotten quotes for $1000 (Pentair 1.5 HP Superflo VS) and $1400 (Pentair 3 HP Intelliflo). The Intelliflo is what they are all pushing, but, if you don’t know what your doing at set it too high, you could damage your equipment. I figured I’d also have to hire a pool service at $100/month to change the settings for each season. The Pentair Superflo VS looks much simpler to operate, but all the “Pros” tell me I wouldn’t save as much in electricity.
In my circumstances, these variable speed pumps would cost me an arm and a leg and have a terrible warranty. Read the reviews on amazon, read the complex warranty, calculate each month’s electricity costs.
Thank you for the feedback JMK.
Hello Mark - The Law of Affinity explains the relationship between motor speed, flow rates, and energy consumption. In other words, a variable speed set at a low rpm will require less energy than a low HP single speed motor.
Pool & Spa News has a good article explaining the physics behind variable speed pumps. It’s worth a read if you want to understand more about the benefits of variable speed pumps.