CFM vs. MPH: Which is Important for a Leaf Blower?

If you are looking for a new leaf blower vacuum, there are a few things you will need to consider. For example, one big decision is whether to opt for a gas-powered model, an electric corded one or a battery powered version.

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Along with this, one of the most important things you will be taking into consideration is the power of the machines you are looking at – but how do we measure it?

How to Measure Leaf Blower Power?

How to Measure Leaf Blower Power

There are several ways to measure the power of a leaf blower – you may see the engine capacity quoted in ccs for gas models, while with rechargeable versions, you will often be told the voltage of the battery. However, the two key numbers to note are air speed (measured in Miles Per Hour, mph) and air displacement (measured in Cubic Feet per Minute, CFM).

What do these numbers mean? And which is more important? Let’s have a look at these questions now.

If you want a preview, here’s a video of what a blower rated at 110mph and 600CFM can do. When you’ve finished reading the article, you might want to come back and watch it again once you understand what the numbers mean.

Leaf Blower Miles Per Hour (MPH)

Leaf Blower Miles Per Hour (MPH)

Miles Per Hour is the easy one. We all understand that this is how we measure speed, and the most familiar example is when we talk about the speed of cars on the road. Specifically, it tells us how many miles something will travel if the speed remains constant for one hour.

In terms of a leaf blower, this tells us how fast the air is traveling when it leaves the blower. Another way to put it is that it tells us how far the air would travel in one hour if the speed remained the same.

For example, if we say that the air speed is 100mph, we are saying that the air would travel 100 miles in one hour if it didn’t slow down (or speed up).

Leaf Blower Cubic Feet per Minute (CFM)

Leaf Blower Cubic Feet Per Minute (CFM)

Cubic Feet per Minute is perhaps more unfamiliar, but it isn’t particularly difficult to understand. This is a measurement of the volume of air – in cubic feet – that is expelled from the nozzle of a leaf blower in one minute.

For example, if a blower has a rating of 100CFM, in one minute, it would expel 100 cubic feet of air. To help you visualize it, that’s roughly the equivalent to just under 750 gallons!

So far so good.

So which should you look at when buying a leaf blower?

So which should you look at when buying a leaf blower

All this theory may be very interesting, but the most important question is, which should you look at when choosing a new leaf blower? To give an answer, let’s look at a couple of examples to help us understand how wind speed and air displacement determine the blower’s performance.

Imagine you have a leaf blower that has a wind speed of, say, 200mph. However, also imagine that the opening at the nozzle is only as wide as a drinking straw.

If this were possible, it’s easy to imagine that this blower wouldn’t be very effective for clearing leaves. This is because although it has a high wind speed, the volume of air coming out of the blower is far too low to be useful for moving large quantities of leaves.

Now imagine the opposite. Imagine a large door with wind blowing through it at about 10mph. Although a high volume of air would pass through the door in a minute, it wouldn’t be moving fast enough to do more than rustle a few leaves on the floor.

So what conclusion can we draw from these two examples? What these two examples show us is that high wind speed or high air displacement alone is not enough – you need a combination of both for a leaf blower to be useful.

What you should look for

What you should look for

When looking at different leaf blowers, you should always make sure you look at both ratings. But what ratings constitute a “good” amount of power?

The answer to this question depends on the type of blower you are looking at as well as what you need it for.

Battery powered leaf blowers are often the least powerful types, although some of them can give you high levels of power for shorter periods.

With these machines, a rating of around 120MPH with 400CFM would give you plenty of power to take care of most leaf clearing tasks in a regular-sized yard.

With corded electric blowers, higher ratings are possible, with speeds of up to 250MPH and displacement of around 600CFM, although you are more likely to find blowers with a high score for just one of these rather than both.

In this case, as long as neither score seems excessively low, the blower should still be able to give you enough power to clear the leaves from your yard.

Gas leaf blowers generally give you more power again, and backpack leaf blowers are designed to give you more power than handheld versions.

At the top end of the scale are walk behind leaf blowers. With these, while you are unlikely to find wind speeds of above 250mph, you can find some models pushing 3,000CFM.

This represents the ultimate in blower power, and these machines are intended for the biggest, toughest jobs.

What to be careful about

What to be careful about

As a rule, the most important thing is to take notice of both ratings and make sure that one is not significantly lower than you would expect for a blower in its category.

For example, a blower with 400CFM but only around 90MPH wind speed would probably not be able to clear more than a few leaves from a patio.

Be wary if one score is prominently displayed but the other is conspicuously absent. If a blower has good ratings in both, they should both be proudly displayed – so if one is missing, it could be an indication the blower is lacking in that department.

No magic formula – understand what the numbers mean and decide

If you don’t have experience using leaf blowers, these numbers can all seem quite abstract since it’s difficult to visualize what it means when you have the tool in your hand.

Perhaps the best way to understand what represents a good score for a blower in a particular category is to compare several similar blowers. This will quickly give you a feel for what most models can offer – and this way, you will be able to choose the model that best matches your requirements.

Don’t forget to pin it!

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