Canopy Cleaning vs Duct Cleaning: What's the Difference — and Do You Need Both?

A question that comes up regularly from commercial kitchen operators — particularly those new to managing extract system compliance — is what's actually different between canopy cleaning and duct cleaning? And do you need both?

The short answer is yes, you need both. But understanding why requires a quick look at how a commercial kitchen extract system actually works.

How a Commercial Kitchen Extract System Works

When you cook in a commercial kitchen, heat, steam, smoke and grease-laden vapour rise from the cooking equipment. The extraction canopy, positioned directly above the cooking line, captures this vapour and draws it into the extract system. From there, it travels through ductwork — sometimes a few metres, sometimes tens of metres, sometimes through multiple floors or ceiling voids — to reach an external discharge point where it exits the building.

Grease is deposited throughout this entire journey. Every surface that grease-laden vapour touches accumulates a deposit: the canopy hood, the filter frames, the plenum chamber above the filters, and every metre of duct between the canopy and the outside. The fan at the end of the run — which drives the whole system — also accumulates grease on its impeller blades and motor housing.

What Canopy Cleaning Covers

Canopy cleaning refers to the cleaning of the extraction hood and its directly associated components. This typically includes:

• —The canopy body — internal surfaces of the hood, including the sides, back and top of the extraction unit
• —Filter frames and filter channels — the housing that holds the grease filters in position
• —Grease filters — the baffle or mesh filters that capture the primary grease load from rising vapour
• —The plenum chamber — the air collection space above the filters where grease accumulates before the duct run begins

Canopy cleaning makes the visible parts of your extraction system look clean and removes the primary grease accumulation at the point closest to the cooking equipment.

What Duct Cleaning Covers

Duct cleaning covers the extraction ductwork between the canopy and the external discharge — everything beyond the plenum chamber. This is the section of the system that is invisible during normal kitchen operation, hidden inside walls, ceiling voids, risers and roof spaces.

Duct cleaning requires access hatches at appropriate intervals along the duct run. Contractors use specialist tools — brushes, vacuum systems, chemical degreasers — to remove grease from the full internal length of the ductwork. A thorough clean covers every accessible section from the canopy connection to the external grille or discharge point.

Fan cleaning is also typically included as part of a full system clean, covering the impeller blades, fan housing and discharge arrangements.

Why Canopy Cleaning Alone Is Not Enough

Here is the critical point: the ductwork is where the greatest fire risk accumulates.

Grease deposits in ductwork harden over time. Unlike the soft, fresh grease that accumulates on canopy surfaces during normal service, duct grease that has been in place for months or years becomes a thick, sticky, highly flammable deposit. If a grease fire at the cooking surface reaches this accumulated duct grease, the result can be a fast-moving duct fire that spreads through the building.

TR19 guidance from BESA is explicit that a compliant extract system clean covers the full system — canopy, ductwork, and fan. A clean that only addresses the canopy and filters does not constitute TR19-compliant cleaning, will not produce compliant post-clean documentation, and will not satisfy the requirements of a commercial insurer in the event of a claim.

What the Post-Clean Report Should Show

After a complete professional extract clean, your post-clean report should confirm that the following were all addressed:

• —Canopy and hood cleaning
• —Grease filter cleaning or replacement
• —Duct cleaning — specifying which sections were accessed and cleaned
• —Fan cleaning
• —Any access hatch locations inspected

If a post-clean report or certificate only mentions canopy or filter cleaning without referencing the ductwork, the job was not a complete system clean.

Getting Both Done in Pembrokeshire

We arrange complete commercial kitchen extract cleaning — canopy, ductwork and fan — for food businesses across Pembrokeshire and West Wales. Every clean includes post-clean documentation confirming the full scope of work.

Contact us with your kitchen details to arrange a tailored quote.