The difference between the two is that variable speed pumps allow you to adjust the flow rate of water through the circulation system, while single speed pumps only have one speed. As you can see, the energy cost is almost identical; however, the variable speed pump turns it over more than twice as often.
When you are shopping for such a pump, you need to look at all of your options and make sure that you are fitting your needs. Shopping around a little will save you money initially and in the long run. Take a look at our list and find one of the best pumps on the market.