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CFM vs MPH

CFM vs MPH Leaf Blowers - CFM vs MPH

When selecting a backpack leaf blower, most people go directly to the technical specifications to find out what the blower is capable of. A potentially misleading factor that confuses many individuals is the MPH, or miles per hour, that a blower can push. This spec is often highly touted by the manufacturers, but it is often not a factor that should be focused on by the consumer.
A better specification to focus on is the CFM, or cubic feet per minute, of air volume that the blower is capable of pushing. It is the volume of air moved, not the speed of the air flow, which has the biggest impact on moving leaves and other debris. You will often see two CFM values reported for a blower. These are the CFM in the housing and the CFM through the tube. It is best to focus on CFM through the tube, as it is this volume of air that you will actually be directing towards your debris.

Consider the following example as it relates to MPH of air flow. Which one do you think is more capable of moving debris and leaves:
150 mph of air flowing through a straw
or
150 mph of air flowing through a 3 inch tube?

The air flowing at 150 mph through a straw is much less effective than 150 mph of air moving through the larger tube. This is due to the fact that a LARGER VOLUME of air is capable of moving through the larger tube than the straw.
So CFM through the pipe is a much more effective measure when determining the raw power of a blower. It is the volume of air that is actually responsible for moving debris. The larger the volume of air, and the more concentrated it is, results in more air being available to push grass, leaves, and other debris.

So in short, if you are looking for raw power, then buy the blower with the highest CFM ratings that your budget allows. Don’t be fooled by manufacturers that focus on their MPH ratings.