4 Ways To Test Range Hood Suction (And Why It’s Not Pulling Air)

Do you need an easy method to test the suction on your range hood? You are in the right place!

In this guide, we'll cover...

  • Using a piece of paper to test for suction
  • Using toy smoke canisters to visualize the hood suction
  • Tips on diagnosing why the range hood is not working
  • Let's get started!
how to test range hood suction

How To Test Range Hood Suction

Here are my basic steps to check a range hood's suction strength:

#1. Toilet Paper Test

The easiest way to test range hood suction is with the toilet paper test.

Simply turn on the range hood, and place a piece of toilet paper underneath the filters. If the toilet paper stays stuck to the underside of the range hood, there is suction.

The strength of the suction can also be indicated by how quickly the toilet paper gets pulled stuck to the underside. Keep the paper a few inches from the range hood, and then turn on the exhaust. How forcefully the paper gets pulled towards the hood can tell you the suction strength.

Instead of using toilet paper, homeowners can use a piece of paper, paper towel, or even a feather.

#2. Smoke Test

Homeowners can purchase a non-toxic toy smoke canister, light it, and place it in a pan underneath the hood.

This test is a great way to visualize the strength (or lack thereof) of the suction as it gets pulled towards the hood.

If there is a makeup air system, homeowners can place another smoke canister at the exterior vent where makeup air is pulled in. I recommend using a different color for the makeup air system in order to see how it works together with the range hood.

#3. Check The Exterior Hood

Homeowners can check the exterior hood for suction.

Simply turn on the range hood and locate the exterior hood or cover on the outside. If you put your hand on the exterior cover, there should be strong airflow towards the outside. The flapper should be pushed open with the strong airflow coming from the hood.

If there isn't strong airflow, there must be an obstruction along the vent or some other defect.

#4. Measure Suction With A Wind Speed Gauge

Homeowners can purchase a cheap wind speed gauge which is known as an anemometer. This gives homeowners a quantitative way to measure the suction as compared to just a qualitative 'feel' of it.

I recommend cycling through the different hood fan speeds to see how the wind speed gauge changes. The wind speed gauge can be used on the inside just below the hood filters as well as on the outside at the cover.

how to test range hood suction (1)

Range Hood Troubleshooting For Not Pulling Air

Here are a few tips on diagnosing a range hood that has low suction...

#1. Vent Obstruction

Probably the most common reason for low suction on a range hood is some type of obstruction along the duct.

Birds like to nest in ducts and homeowners should check the exterior cover with a flashlight to make sure there isn't a birds nest or a dead animal in the duct.

#2. Dirty or Clogged Filters

Some people just don't know that range hood baffle filters need to be frequently cleaned. And if there is a mesh filter, they need to be periodically replaced entirely.

An easy way to test if the dirty filters are causing low suction is to remove them and turn on the range hood. If suction is restored or increased, then dirty filters are the culprit.

Read Also >> Our 8 Steps To Clean Range Hood Baffle Filters

#3. Range Hood Set To Recirculating Mode

Some range hoods have a small switch on the hood that moves a damper to put in recirculating mode.

Likewise, there may be a metal plate on the duct exit that was never removed from the hood. If the range hood is new, carefully inspect it with a flashlight to make sure it isn't accidentally in recirculating mode and that all metal knockout plates have been cleared.

Read Also >> How Do Recirculating Range Hoods Work?

#4. Makeup Air System Needed

If the home is very tight and air sealed, a makeup air system may be needed. Makeup air systems provide fresh outdoor air as a replacement for the air the range hood removes from the kitchen.

If the home is thoroughly air sealed, there may not be enough makeup air for the range hood to work properly — especially if the hood is rated at 400-cfm or greater.

An easy way to test if this is the problem is to open a kitchen or nearby window when the range hood is on. If the suction increased with the open window, then your range hood likely needs a makeup air system.

Read Also >> How To Pick The CFM For Your Home's Range Hood?

Final Thoughts

A range hood that has low suction or isn't venting at all is a perplexing problem.

The most common reason is a vent obstruction but some other issues can also be the culprit. Homeowners should always check the exterior cover as one of the first things to inspect to make sure there isn't an animal's nest blocking the exit.

I hope you enjoyed my guide, ask me any questions below or share your range hood story.

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2 thoughts on “4 Ways To Test Range Hood Suction (And Why It’s Not Pulling Air)”

  1. Hi Arie. I am looking at a Best rangehood UCB3I, there is only one fan which is on the left side, CFM is 550. I went to a store that displays this range hood, when I put paper on the left, there is suction but there is no suction on the right. Would that be a problem when I cook on the right side of my electric stove as there will be no suction?

    Reply

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