At GreatVacs a question we get all of the time is what is the most powerful vacuum? If you do a google search online you will find that there is almost no data for CFM of airflow data for vacuum cleaners. Airflow (how much air is moved in a minute) is the best indicator of how well a vacuum cleans your floor. Suction means nothing and Airflow means everything. We have found that most manufactures don't like this data to be public because then its easy to compare vacuums. If you were making a vacuum cleaner that had 95 CFM of airflow and your competitor had 105 cfm of airflow then it would be hard to sell your vacuum. That is why there is typically 4 ways power is measured.
1. Release no data just talk in generalities.
2. Measured in CFM of Airflow.
3. Measured in Water Lift (measure suction not airflow).
4. Measured in HP (worthless in vacuums).
Because of this here at GreatVacs Labs we measure Airflow ourselves. We have one of the only CFM tools designed for vacuum cleaners (see image above). As part of that we want to mention our disclaimer. Our data might be slightly different than the Manufacture data. If it comes between our data and the Manufacture data then go off of the Manufacture data. With our tool there can be up to a 3% variation in test results because there are other variables to consider. We test most of our vacuum cleaners used not new. We feel all vacuum tests should be done that way. If we are testing a used vacuum you might find slightly different performance as new. We don't guarantee to have the same exact data as the Manufacture data but our tests data is accurate and uniform among the vacuums we test. For example if we test the CFM of a Kirby vacuum and a Dyson vacuum the data might be slightly different than the Manufacture but the difference in airflow should be the same between our 2 tests as we use the same methods of testing. So here is our official disclaimer. All information and statements are merely our opinions. All official and technical information on vacuum cleaners is not contained within this information. For that information you need to contact the vacuum manufacture or your local distributors. We are not a distributor nor are we associated in any way with the most of the brands we test. We don't claim to include all information in our documents but if there is something that you would like us to add, please let us know.
Some brands will try and boost the CFM ratings of their products by doing the test without a bag or a HEPA filter. Our testing will always include a installed bag or HEPA filter just like it would be while you are vacuum cleaning. The picture above shows how we did tests on a Kirby vacuum cleaner. You will notice we measured CFM from the vacuum head not the hose. We tested the CFM on a Kirby Diamond based on the vacuum head at 114.6 CFM. When we put the hose on and tested the hose it came out to 99.5 CFM at the end of the hose. This shows the principle that for every foot of hose you vacuum through you loose airflow.
We are providing this data as a service to you. We know there is a lot of confusion about vacuum cleaners so we hope that it is helpful in helping you choose the best vacuum for you and your family. If you want the most accurate data then we suggest contacting the Manufacture as we don't pretend to be 100% accurate.
If you have any questions on the best vacuum for you don't hesitate to send us a email at firstname.lastname@example.org :)