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How Does a Vacuum Cleaner Work? [Simple Explanation]

Written by James Hall |

How does a vacuum cleaner work?

Have you ever wondered how vacuums collect so much dirt, hair, and dust? Here’s our simple guide to how vacuum cleaners work.

It’s hard to imagine life without a vacuum cleaner. Just think of trying to clean carpets and hard floors using only manual tools!

In this article, we’ll take a look at the principles behind vacuum cleaners and how they work. We’ll also discuss what affects a vacuum’s performance and how the system changes for a bagless vacuum.

How Does a Vacuum Work?

Vacuum cleaners have a motor that drives a fan. The fan pushes air into the vacuum cleaner and out of the exhaust, which creates a partial vacuum inside. Air rushes into the vacuum’s floorhead (or hose) to equalise this pressure difference, bringing in dust or dirt that’s then collected by the bag or canister.

The Basics of a How a Vacuum Cleaner Works

While modern machines can have complex designs, there are three key components of a bagged vacuum cleaner. These are the motor, fan, and bag.

Here’s how these components combine to generate suction at the cleaner head or hose:

  1. When the power is switched on the, the motor begins to turn. Vacuum motors are typically located in the floorhead for an upright vac, or in the main body of a cylinder vacuum.
  2. This motor drives the fan, which is also located in the floorhead. Some vacuum cleaners have an additional fan for cooling the motor, but this isn’t part of the suction process.
  3. The fan is designed to push air into the vacuum cleaner. The fast rotating impeller (up to 35,000 RPM) creates negative pressure inside the vacuum, which is lower pressure than the surrounding atmosphere. Air from outside the vacuum rushes in to fill this area of negative pressure.
  4. As long as the fan is running, there is a continuous stream of air entering the vacuum and exiting via the exhaust. This is what we call suction. The exhaust is essential, otherwise air from the fan would have nowhere to go. Air also passes over the motor to keep it cool.
  5. The air pulls dirt, hair, and other debris with it into the vacuum, where it is collected by the bag. The bag has porous sides that acts as a filter, allowing air to pass through but trapping dirt. Some vacuums have a powered brush bar, which stirs up dust and dirt to make it easier for the vacuum to pick up.
  6. Many vacuums also have an exhaust filter. This is the final step of the filtration system and is designed to remove fine particles to prevent them being released into the air.

This is a simple overview of how vacuum cleaners work, but modern machines are often complex devices that have additional design features. Vacuums have continued to get smaller, more powerful, and more advanced, although the underlying principle of using a pressure difference to create airflow is the same.

It’s worth noting that vacuums actually only create a partial vacuum. This is enough for sucking up dirt around the home though (and the name “partial vacuum cleaner” doesn’t have the same ring to it!)

If You’re Still Struggling to Imagine How a Vacuum Works…

One of the best examples of the principles of a vacuum cleaner is to think of drinking through a straw. When you suck the straw, you’re removing the air inside it to create negative pressure (i.e. pressure that’s lower than the atmosphere around it). This causes water to flow into the straw to fill this area of negative pressure.

What Makes Some Vacuums More Effective Than Others?

All vacuums clean using the same basic principles, yet some models are much more effective than others. What causes these difference?

The most obvious difference is the motor power. Vacuums in the EU are limited in how much power then can draw (900W is the current maximum), but the best models use this power more effectively due to an efficient motor.

Airflow through the vacuum cleaner is also important. The top vacuum cleaners are designed to maximise airflow, which increases suction power and cleaning performance.

Other factors that can affect a vacuum’s cleaning performance include whether it has a rotating brush bar, which tools are being used, and whether there is any air leakage. The width of the intake opening also affects suction power, with smaller openings generating more suction. This is why smaller tools can often pick up larger debris that wider ones.

What About a Bagless Vacuum Cleaner?

Bagless vacuum cleaners use the same principle of driving a fan to create a pressure difference, but instead of filtering the air through a bag they have a cyclonic design.

Air is spun in a circular pattern inside the vacuum to force dust and other debris to the side of the canister. As the debris moves out of the airflow, it drops into the canister, while the air continues its path through the vacuum cleaner.

One of the advantages of a cyclonic design is that you don’t need to buy replacement bags. Air also doesn’t need to pass through all the collected debris, as with a bagged design, which prevents suction loss as the canister fills up.

To learn more, read our guide to cyclonic vacuum cleaners.

Tip: The idea of a bagless vacuum cleaner has been around for a long time, but Dyson was the first to popularise the combination of a bagless and cyclonic vacuum for home use.

How Do Cordless Vacuums Work?

Cordless vacuums cleaners also use the same principles to generate suction power. The difference is that they are powered by a battery, rather than the mains supply.

Battery power isn’t as consistent as plugging into the mains supply – and it’s also limited before needing to be recharged. That’s why cordless vacuums tend to have less powerful suction.


At a basic level, vacuum cleaners are simple machines. They use the concept of negative pressure to cause air to rush into the vacuum, bringing dust, hair, dirt, and anything else that gets caught up in the airflow.

Modern vacuums are considerably more complex than those produced in the past though. While the principles are the same, the best vacuum cleaners have excellent filtration, energy efficient motors that still provide plenty of power to the fan, and optimised airflow.

Do you have any questions about how a vacuum cleaner works? Please let us know in the comments section.

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