The only way we can actually save on pumping costs without risking green pool water is to switch out our single-speed pump for a variable speed pump. Now a lot of people will say, well, if you’re just going to be using a pump that runs at a lower speed, it would mean that we would have to run it for much longer to get the proper filtration and that would basically cost the same right? Well, that statement is partially correct in the sense that we would have to run the pump longer but the cost is between night and day.
The phenomenon involved in this reduction in cost is known as The Pump Affinity Laws. Without going too deep into the science, the best way to explain this is if we needed to reduce the flow rate of our impeller by 50% it doesn’t mean that we have to reduce our power usage by half, but instead, we actually reduce power usage by FOUR times.
In layman’s terms, taking the same example we had earlier with a 40,000L pool with a 1.5HP single speed pump, with an equivalent variable speed pump running at half the speed, we would need to run it at 16 hours. BUT we would be running it at a quarter the cost as we would a single-speed pump. Basic math notwithstanding, we would be saving 50% in energy costs in achieving the same amount of filtration!
Note: This is a greatly simplified explanation, but many variable speed pumps like the Water TechniX Pump Dual ECO Variable speed have other optimizations that will lower energy consumption up to 75%