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Why Is My Kitchen Exhaust Not Pulling Smoke? 8 Common Causes

Smoke rolling out from under the canopy? Poor extraction has several possible causes. Here are eight of the most common, what you can check safely, and when to call a specialist.

By Apex Commercial Exhaust · 6 November 2026 · 6 min read

Key takeaways

Blocked filters and greasy ducts are common, easy-to-check causes of poor extraction.
Fan faults, belts, airflow imbalance and design issues need a qualified technician.
New or larger cooking equipment can exceed what the canopy was designed for.
Check filters first; never climb onto roofs or open ducts yourself.
Cleaning can support airflow but does not fix mechanical or design problems.

When smoke and heat roll out from under the canopy, service gets uncomfortable fast. Poor extraction has several possible causes, and some are simple to check. Here are eight of the most common, and who can help with each.

8 common causes of an exhaust not pulling smoke

Blocked or dirty filters

Heavy grease restricts airflow. Check and clean filters first.

Missing or badly fitted filters

Gaps change how air moves through the canopy.

Grease build-up in ducts

Deposits in the plenum and ducts can restrict airflow.

Dirty fan

Grease on blades and impellers affects the fan.

Fan or belt faults

Worn belts, bearings or motor issues need a technician.

Not enough make-up air

If replacement air cannot enter the kitchen, extraction suffers.

Changed cooking equipment

New or larger appliances may exceed the canopy’s design.

Design or balance issues

Canopy size, position or duct layout may need review.

What you can safely check

Stay safe: never climb onto the roof, open ducts or dismantle the fan. Leave that to trained specialists.

Who to call

Read who handles which problem

Grease build-up (causes 1 to 4): a kitchen exhaust cleaning specialist. Within the agreed scope, Apex cleans all accessible and reachable areas of the canopy, ducts, fan and filters, and notes visible concerns.

Mechanical and design issues (causes 5 to 8): a qualified mechanical or ventilation contractor. The ABCB’s guide to NCC clause F6D12 explains that kitchen exhaust hoods must comply with AS 1668.1 and AS 1668.2, which deal with design and installation.

Cleaning can support airflow, but it does not fix fan faults, airflow imbalance or design problems.

Why it matters for fire safety

Grease build-up that restricts airflow is also fuel. The restaurant fire safety guidance published with Fire and Rescue NSW lists fatty residue in range hoods and ducting among common causes of restaurant fires.

Frequently asked questions

Will cleaning fix poor extraction?

If grease is the cause, cleaning can help. Fan faults, make-up air and design problems need a qualified technician.

Why did extraction get worse after we added a new fryer?

New or larger equipment can exceed what the canopy was designed for. Ask a mechanical contractor to review the system.

Is smoke in the kitchen a fire risk?

Poor extraction can indicate grease build-up, which is combustible. Arrange an assessment promptly.

References & further reading

Government, regulator and Standards sources mentioned in this guide (links checked November 2026; requirements can change, so check the current version):

Australian Building Codes Board (ABCB), NCC guide: F6D12 Kitchen local exhaust ventilation
Fire and Rescue NSW, NSW Rural Fire Service, ACT Fire Brigade and ACT Rural Fire Service, Restaurant fire safety

Need help with your kitchen exhaust? Apex Commercial Exhaust cleans canopies, exhaust ducts, rooftop fans and grease filters for commercial kitchens across Melbourne and Victoria.

This article is general information only and is not legal, insurance or compliance advice. Requirements for your kitchen depend on your system, building and obligations.

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