How to Measure Vacuum Cleaner Suction Power

Wondering how to measure vacuum suction power and what the numbers actually mean? Whether you're testing your current vacuum or comparing models, understanding suction metrics is key to choosing the right cleaning tool for your home.

This guide walks you through the tools needed to measure suction accurately, including pressure gauges and airflow meters. You'll then learn three industry-standard methods—Air Watts, Water Lift, and Pascals (Pa)—each offering a different lens on how well your vacuum performs. We break down when and how to use each method, so you can get clear, reliable readings.

Finally, we explore real-world factors that affect suction power, from clogged filters to motor wear, and how to fix them. By the end, you’ll know how to test, interpret, and improve your vacuum’s suction for better cleaning results.

Tools You Need to Measure Vacuum Suction Power

To accurately measure vacuum suction, you can use a few accessible tools. The table below summarises what each tool does and why it’s useful:

This setup works well whether you're testing a household vacuum or comparing industrial units in the Australian market.

Using Air Watts to Measure Suction Power

Air Watts is a combined measure of both suction power and airflow. To measure Air Watts, you need to gather two key pieces of data: CFM (Cubic Feet per Minute) and Water Lift. Here’s a clearer step-by-step process:

Step 1: Measure the Airflow (CFM)

The first step is to measure the airflow (CFM), which is the volume of air the vacuum can move in one minute. This is typically measured in Cubic Feet per Minute (CFM).

• Tool used: Hot Wire Anemometer or a Calibrated Flow Meter.
• How to measure: Place the anemometer or flow meter at the vacuum’s suction inlet (usually where the hose connects). The device will measure how much air the vacuum is drawing in.

Why it matters: High airflow (CFM) is crucial for cleaning larger areas quickly, as it indicates how much air the vacuum can move, allowing it to pick up dust and debris more efficiently.

Step 2: Measure the Water Lift

Next, measure the Water Lift, which tells you about the vacuum’s suction strength. Water Lift measures how high the vacuum can lift a column of water, and it indicates how much suction force the vacuum is generating.

• Tool used: Manometer or Vacuum Gauge.
• How to measure: Attach the manometer to the vacuum’s suction port. The manometer will show how high the water column is lifted as the vacuum operates.

Why it matters: A higher Water Lift means stronger suction, allowing the vacuum to pull debris from deeper surfaces, such as carpets or cracks.

Step 3: Calculate Air Watts

Now that you have both CFM (airflow) and Water Lift (suction strength), you can calculate Air Watts using the following formula:

Air Watts = CFM × Water Lift ÷ 8.5

For example, if a vacuum has a CFM of 100 and a Water Lift of 100 inches, the Air Watts would be:

Air Watts = 100 × 100 ÷ 8.5 = 1176.47

Why it matters: Air Watts is a combined measure of suction strength (Water Lift) and airflow (CFM). A higher Air Watts value indicates better overall cleaning power, meaning the vacuum can pick up more debris and clean more efficiently.

Using Water Lift to Measure Suction Power

Water Lift is a key metric that measures the strength of your vacuum’s suction by how high it can lift a column of water. It tells you about the vacuum’s pulling force. Here's a step-by-step breakdown:

Step 1: Set Up the Manometer

To measure Water Lift, you’ll need a Manometer or Water Manometer. These devices are designed to measure the vacuum’s suction by observing how high a column of water can be lifted.

• Tool used: Manometer (preferably a water manometer for more accurate readings).
• How to set up: Attach the manometer to the vacuum's suction port or hose. Ensure it’s secure so that there are no air leaks during the test.

Step 2: Turn On the Vacuum

Once the manometer is connected, turn on the vacuum and let it stabilize for a moment.

• Why it matters: You want to allow the vacuum to reach a steady operating condition before taking the measurement. This ensures that you're getting an accurate reading of the vacuum’s performance.

Step 3: Measure the Water Lift

As the vacuum operates, the water manometer will show you how high the water column rises. This height is your Water Lift value. Higher readings indicate stronger suction.

• Why it matters: A higher Water Lift means your vacuum has a stronger suction force. It’s especially important for deeper cleaning tasks, like pulling dirt from carpets or upholstery.

Step 4: Interpreting Results

The Water Lift value is typically measured in inches of water. The higher the value, the more powerful the suction.

• For example, if your manometer shows a water lift of 100 inches, this indicates that the vacuum has a strong suction force. This is ideal for deep cleaning tasks.

Using Pascals (Pa) to Measure Suction Power

Pascals (Pa) measure vacuum pressure, which is another important factor in suction performance. This method provides an accurate reading of suction strength. Here's how to use Pascal values to measure suction power:

Step 1: Attach the Electrical Pressure Transducer

To measure suction pressure in Pascals, you will need an Electrical Pressure Transducer. This tool converts vacuum pressure into an electrical signal, which is then displayed digitally.

• Tool used: Electrical Pressure Transducer.
• How to set up: Attach the pressure transducer to the suction port or hose of your vacuum.

Step 2: Turn On the Vacuum

After the transducer is properly connected, turn on the vacuum and let it stabilize.

• Why it matters: Like with other tests, the vacuum should run for a moment to stabilize and provide an accurate reading.

Step 3: Read the Measurement

The transducer will convert the pressure into a digital reading in Pascal (Pa). The higher the number, the stronger the suction pressure.

• Why it matters: Higher Pa values indicate a vacuum with stronger suction power. This is important for tasks requiring fine precision, like cleaning tight spaces or deeply embedded dirt.

Step 4: Interpreting Results

• Higher Pascal readings mean greater suction power. This method is great for precision cleaning because it shows how much force the vacuum is generating.

What Affects Vacuum Suction Power (and How to Fix It)

Vacuum suction power can drop over time, but many causes are preventable. Here are the most common factors that affect suction and what you can do about them:

Clogged Filters

Dirty or blocked filters reduce airflow and weaken suction. Wash or replace your vacuum’s filters regularly—check your manual for cleaning intervals. HEPA filters should be cleaned every 1 to 3 months depending on usage.

Blocked Hose or Nozzle

Dust, hair, or debris stuck in the hose or nozzle can block airflow. Detach the hose and use a broomstick or compressed air to clear any blockages. Inspect the nozzle and vacuum head for clogs, especially if suction suddenly drops.

Leaking Seals

Air leaks around the hose connection, dustbin, or filters reduce vacuum efficiency. Ensure all components are properly sealed and fitted. Check rubber gaskets for wear and replace if needed.

Worn Brush Roll or Belt

A worn or tangled brush roll can reduce dirt pickup. Clean the roller regularly and replace it if bristles are damaged. If your vacuum uses a belt, check for slack or cracking and replace when needed.

Other Minor Factors

Some environmental or technical elements may also influence suction, though their impact is usually small:

• Voltage Fluctuations: Cordless vacuums may lose suction if the battery is weak. Always ensure it's fully charged for best performance.
• Air Temperature and Humidity: Extreme heat or moisture can affect motor efficiency and airflow slightly, but this is rarely noticeable in daily home use.
• Altitude: At high altitudes, thinner air may reduce suction performance marginally. However, this mostly affects industrial vacuums.

While these aren’t common concerns for most Australian households, being aware of them helps you troubleshoot if other fixes don’t solve the issue.

What is the difference between suction power and air suction?

Suction power is the total strength of the vacuum, including both suction pressure (Water Lift) and airflow (CFM). Air suction refers to how well the vacuum pulls air, usually measured by CFM. Suction power is a more complete measure of how effective the vacuum is at cleaning.

What should I do if my vacuum’s suction power decreases over time?

If your vacuum's suction power decreases:

• Clean or replace the filters.
• Check for clogs in the hose or brush roll.
• Ensure there are no leaks in the system.
• Empty the dustbin or replace the bag.

How do I know if my vacuum has strong suction?

You can tell if your vacuum has strong suction by checking its Air Watts, Water Lift, or CFM values. Higher Air Watts and Water Lift generally indicate stronger suction.

Does higher wattage in a vacuum mean better suction?

Not always. Wattage refers to the power consumed by the motor, but suction power depends more on factors like Airflow (CFM) and Water Lift. A vacuum with higher wattage may not always have better suction if these factors aren’t optimized.

How much suction does the average vacuum have?

The average vacuum typically has between 100-200 air watts of suction power. Higher-end models can have 200-300 air watts for better performance, especially for deep cleaning tasks.

What are the suction power ratings for different vacuums?

• Low suction (less than 100 Air Watts): For lightweight vacuums, suitable for light tasks like hardwood floors.
• Medium suction (100-200 Air Watts): Common for most home vacuums, ideal for general carpet cleaning.
• High suction (200-300 Air Watts): Found in high-end models, designed for deep cleaning thick carpets.
• Professional-grade suction (300+ Air Watts): Used in commercial vacuums, providing maximum power for large areas and heavy debris.

Conclusion

Measuring vacuum suction power doesn't have to be complicated. Whether you're comparing models or troubleshooting performance, understanding Air Watts, Water Lift, and Pascals gives you a clear picture of what your vacuum can do. With the right tools and a basic testing setup, you can ensure your vacuum is delivering the suction it promises—every time you clean.

If you're still evaluating which vacuum suits your needs, check out our full guide to the best vacuum suction power based on cleaning surfaces and vacuum types. For those focused on deep cleaning, don’t miss our roundup of robot vacuums with best suction power for deep cleaning. You can also explore strong suction robot vacuums from Narwal Australia—a trusted name in intelligent floor cleaning solutions designed for Australian homes.