Have you ever wondered why some vacuum cleaners seem to pick up dirt and debris easily while others struggle to pick up even the smallest particles? The answer is in the machine’s suction power or airflow.

If you own a vacuum cleaner or are looking to buy one, knowing how important airflow is can make all the difference in how clean your home is.

In this article, I will talk about how suction power is measured and why it is important.

I will also give you tips on how to choose a vacuum cleaner with the best airflow for your needs.

So get ready to breathe easier when your home is clean.

Understanding Airflow and Suction Power in Vacuum Cleaners

Airflow versus Suction Power

Airflow and suction power are two important factors that determine how well a vacuum cleaner cleans.

Airflow is the amount of air that the vacuum motor can move, and it is measured in cubic feet per minute (CFM).

Suction power, on the other hand, is measured in millimeters of water column or Pascals and shows how much force the motor can pull (Pa).

The ideal vacuum cleaner should have a balance of strong suction power and an abundance of airflow.

How Airflow Works in a Vacuum Cleaner

Airflow is created by the vacuum motor, which pulls air from the opening at the cleaning head or tool, through the vacuum cleaner and filter system, and then out through the exhaust port.

Without airflow, there is nothing to pull dirt in and carry it away, which is why suction alone is not effective in carpet cleaning.

Some vacuum cleaners have strong suction but low airflow, while others have strong airflow but weak suction.

For the best cleaning results, there needs to be a balance between the two requirements.

Airwatts: A Controversial Measurement

The term “airwatts” was made to find the “sweet spot” on the performance curve where suction power and airflow work together in the best way.

The formula for air watts is: Air Flow (in CFM) x Vacuum (in inches of water lift)/8.5 = Air Watts.

But there is some disagreement about whether this specification is helpful or just another rating that makes it hard for people to compare products.

Several factors impact airflow in a vacuum cleaner:

  • The amount of suction developed by the suction motor
  • Resistance in the filtration system as it traps dirt
  • Total resistance in all air passages
  • Design of the cleaning nozzle
  • Turbulence in hoses and wands
  • Restrictions on airflow where there are bends or other obstructions
  • The distance and cross-sectional area of passages through which air must travel through the system
  • The quality of paper bags used in vacuum cleaners
  • Accumulated debris

A good-quality paper bag that filters well will let more air through than a cheap paper bag that does not filter well.

When debris builds up, airflow can drop from 2.3 m3/min (80 cfm) to as low as 0.85 m3/min (30 cfm).

Design and Airflow in Vacuum Cleaners

Airflow is the most important factor in figuring out how well a vacuum cleaner can clean.

It refers to how fast air moves through the vacuum cleaner or central vacuum system and is usually measured in cubic feet per minute (CFM).

The suction motor lowers the pressure of the air, which makes the air move.

The easier it is for the air to flow, the better the cleaning performance.

Airflow and Suction: Key Factors in Vacuum Performance

Dirt is moved into the bag or dirt container by a combination of airflow and agitation.

Most of the time, the airflow rating is found by measuring how fast air moves through a vacuum cleaner without a hose or attachments.

While the airflow rating is not a direct rating of the power of the suction motor, it is affected by its suction.

For any given airflow, the speed of moving air is inversely proportional to resistance.

Suction refers to the vacuum motor’s force that generates “pull” of air into the machine.

Airflow is different from suction, but the two are related.

Both suction and airflow are important for figuring out if a vacuum has enough power to be a good cleaning tool instead of a cheap one.

Considerations When Choosing a Vacuum Cleaner

There are a lot of different kinds of vacuum cleaners, so knowing how their airflow and suction power are different can help you decide which brand and model is best for your needs.

When choosing a vacuum cleaner, it is important to find a good balance between suction and air flow.

If there is too much airflow through a vacuum, it might not have enough suction power to pick up dirt and other debris well.

On the other hand, a vacuum with too much suction power might not have enough airflow to move dirt and debris into the dust bag or container.

Impact of Resistance and Maintenance on Airflow

Air flow is also affected by how hard it is for the air to move through the bag and filter system.

Vacuum cleaners with HEPA filters can cost more because they have more resistance than other types of filters.

It is important to remember that filters and bags that are clean are usually used to measure airflow.

As time goes on and filters get dirty and bags get full, air flow will naturally slow down.

This is why filters should be changed often and bags should be changed as needed.

Choosing and Maintaining a Vacuum Cleaner

  • Vacuum Cleaner Specifications: Airflow, Suction, and Air Watts

Before purchasing a vacuum cleaner, customers should consider the airflow, suction power, and air watts, as these factors determine the cleaning ability of the vacuum cleaner.

  • Airflow is measured in cubic feet per minute (CFM) and is crucial for determining the cleaning ability of a vacuum cleaner.
  • Suction, also referred to as vacuum, is expressed in inches of water lift and indicates the maximum pull the motor is capable of.
  • The combination measurement of Water Lift and Airflow is called Air Watts, which has become more standard for the central vacuum industry. The American Society of Testing and Materials (ASTM) recognizes Air Watts as the best way to measure the actual cleaning power of a vacuum system.

When figuring out how well a vacuum cleans, it is important to look at both airflow and suction.

Some manufacturers may use new ratings like “air watts” to confuse customers and make comparisons hard.

Before making a purchase, customers should also think about their needs, such as where the vacuum will be used, how long it will be used, and what it needs to pick up.

Vacuum Cleaner Maintenance for Improved Airflow and Suction

  • Regular maintenance tasks can help improve airflow and suction power in a vacuum cleaner:
  • Empty or change the dust compartment when it’s already 70-80% full.
  • Clean attachments, inspect belts, and check hoses for clogs frequently.
  • Regularly check filters for any sign of wear or damage.

Flooring Type and Vacuum Cleaner Performance

  • The type of flooring affects the airflow and suction power needed in a vacuum cleaner:
  • Static lift measures the strength or how much soil the vacuum can pull from the surface.
  • Airflow helps the dirt and debris travel down the vacuum hose to the tank.
  • The suction required for carpets is not as high as that for hard floors because carpets are more likely to trap and contain dust and dirt.

Cleaning Nozzle and Vacuum Cleaner Efficiency

  • The design of the cleaning nozzle can significantly affect a vacuum cleaner’s ability to clean effectively:
  • Higher air velocity close to the surface leads to better cleaning on carpets.
  • Uprights and power nozzles with revolving brush rolls were developed to remove dirt and grit embedded deep within carpets, as airflow alone is insufficient.

Adjusting Vacuum Height Settings for Optimal Cleaning

  • Adjusting your vacuum’s carpet height settings can make a big difference in cleaning efficiency:
  • Set the vacuum at its lowest for bare floors or thin carpeting.
  • Use the middle setting for slightly fuller carpets.
  • Avoid using the highest height setting on hardwood floors or flat surfaces, as the brush may not reach all areas effectively due to a lack of airflow.

When choosing a good nozzle for your vacuum cleaner, it is more important to think about how well it can pull in air than how powerful the motor is.

Suction capacity is how much negative pressure (lift) your vacuum cleaner can make when its motor is running.

Different household and industrial vacuum cleaners can make different levels of suction power, which is measured in mm water column or Pascal (Pa).

The Importance of Suction Strength in Vacuum Cleaners

When it comes to vacuum cleaners, suction strength is a crucial factor to consider.

It determines how effectively the machine can pick up dirt, dust, and debris from various surfaces.

A vacuum cleaner with weak suction power will struggle to clean carpets, upholstery, and other surfaces, leaving behind dirt and debris.

On the other hand, a vacuum cleaner with strong suction power can easily remove even the most stubborn dirt and debris, leaving your home clean and fresh.

Suction strength is affected by various factors, including the motor power, the design of the vacuum cleaner, and the quality of the filters.

Therefore, when choosing a vacuum cleaner, it’s essential to consider the suction strength to ensure that you get the best cleaning results.

For more information:

Maximize Vacuum Power: Understanding Suction Strength

Myths and Misconceptions about Vacuum Cleaners

  • Common Misconceptions About Airflow and Suction in Vacuum Cleaners

1. Amp Rating and Suction Power

  • Myth: A higher amp rating means better suction
  • Fact: The amp rating reflects energy consumption, not suction capability

2. Bagless versus Bagged Vacuums

  • Myth: Bagless vacuums are more advanced than bagged vacuums
  • Fact: While bagless technology is newer, both types have their advantages
  • Bagged vacuums are typically lighter and have lower filter costs

3. Weight and Cleaning Performance

  • Myth: Heavier vacuums perform better
  • Fact: Weight does not determine a vacuum’s cleaning ability

4. Vacuum Height Setting

  • Myth: Setting a vacuum too low to the carpet will clean it better
  • Fact: Most people set their vacuum too low, which can damage both the carpet and vacuum cleaner

Determining Vacuum Cleaner Performance

Suction power and airflow are the best ways to figure out how well a vacuum cleaner cleans.

  • Strong suction power is needed for thick, plush carpeting
  • Strong motor ability allows airflow to continue under obstructed conditions

Without airflow, there is nothing to pull in dirt and carry it away. This means that suction alone can not clean carpets well.


In the end, airflow or suction power is one of the most important things to think about when buying a vacuum cleaner.

It shows how well the machine cleans your floors and carpets by picking up dirt and other things.

But it is important to remember that high suction power does not always mean that the vacuum will clean better.

Other things, like the design of the brush roll, the filtration system, and the overall quality of the build, also play a big part.

As a vacuum cleaner owner, it is important to know how the airflow rating of your machine affects how well it works.

Regular maintenance, like cleaning or replacing the filters and emptying the dustbin, can also help keep the suction power at its highest level.

Do not get too caught up in the numbers when looking for a new vacuum cleaner.

Instead, think about what you need to clean and look for a machine that has a good balance of power, filtration, and how easy it is to use.

In the end, the best vacuum is the one that fits your cleaning habits and how you live.

So, take your time, do your homework, and make a smart choice.

Remember that a clean home is a happy home, and a good vacuum cleaner can make all the difference.

Cleanliness is next to godliness.

says a well-known proverb.

So, buy a good vacuum cleaner to make your home cleaner and healthier.

Good luck cleaning!

Looking for a new robot vacuum?

Choosing a gadget can be very difficult if you know nothing about the technology.

Some will pay for features they do not need while others may not consider what they really want.

So I created this quick, newbie guide to help you focus on what is really important to you:

The best robot vacuum for you.

Links and references

“Vacuum Technology: Practical Heat Treating and Brazing” by Bodo Gehring,

“Vacuum Science and Technology” by John F. O’Hanlon

“Experimental Study on Airflow Characteristics in a Vacuum Cleaner Dustbin” (research paper)

My article on the topic:

Mastering Vacuum Suction Power: A Beginner’s Guide