Choosing between the CFM and MPH depends on a lot of factors such as the size of the yard, the weight of the blower that you are looking for, and the intensity of leaves falling in the yard. MPH is miles per hour, and CPH is cubic feet per hour. The ideal way to choose between the MPH and CPH is to keep an eye on Newton Force. In simple terms, Newton force is the combination of both MPH and CPH for the outcome. It is also easy to measure one metric rather than comparing both MPH and CPH. So, the dry leaves blower with higher Newton Force is a better purchase.