How does a variable speed pump work?

As compared to a “standard” single-speed pump, the variable speed pumps have adjustable flow rates to maximize efficiency. Rather than running the pump “all day” at a “high horse power”, one adjusts the flow on the variable speed pump to ONLY meet the needs of the pool. For example, one may run the pump on a higher speed for a few hours to get more cleaning action through the in-floor cleaning system, then lower the speed VERY significantly for the rest of the day to only filter the water at a very low pressure. Pumps may now run for more hours but at such a reduces horse power or speed that the savings are significant.