The kitchen hood captures the cooking plume, filters remove part of the grease, the duct carries contaminated air away, and the exhaust fan creates the pull that moves it. These parts share one air path, but they do different jobs and collect grease in different places.
Calling the complete system “the hood” can create a scope problem. A contractor may clean the visible canopy while the restaurant expects the duct and fan to be included. Name each component before requesting a quote or signing a report.
Kitchen Hood: The Capture Point Above the Cookline
The hood or canopy sits above commercial cooking equipment. Its shape and position are meant to collect heat, steam, smoke and grease-laden vapour before they spread into the kitchen.
Grease often shows first along the lower hood edge, filter frame, light area or collection channel. Staff can usually see these surfaces during daily checks, but visibility stops above the filter bank. A clean front face says little about deposits farther inside.
The cookline must also remain within the hood’s intended capture area. Moving a fryer or charbroiler to the edge can let smoke escape even if the canopy is clean. That is a layout or airflow issue, not proof that stronger chemicals are needed.
Grease Filters: The First Collection Stage
Commercial hood filters sit between the cookline and the plenum. They catch a portion of airborne grease while allowing exhaust air to pass. Different filter types have different cleaning and replacement instructions, so staff should use the manufacturer’s directions.
A filter can cause trouble when it is heavily loaded, damaged, missing or installed with gaps. Air and grease then take an unintended path. Never run grease-producing appliances with filters removed simply because the clean set is not ready.
Filter care is usually more frequent than internal duct cleaning because filters receive the grease first. The right interval depends on cooking volume and filter condition. A busy wok or frying line may need closer attention than a low-use reheating station.
Plenum: The Space Behind the Filters
The plenum is the chamber behind or above the filters before air enters the duct. It is easy to overlook because kitchen staff do not see it during a normal surface wipe.
Grease that passes the filters can coat plenum surfaces. Poor filter seating may create heavier deposits in one area. When access is safe, before-and-after records should identify the plenum separately instead of grouping it with the visible canopy.
Grease Duct: The Hidden Route Through the Building
The duct carries exhaust air away from the hood toward the discharge point. It may run horizontally, vertically, through a shaft or across the roof. Direction changes and long runs can create several inspection points.
Grease inside a duct is hidden fuel. Cleaning only the first reachable section can leave deposits beyond a bend or closed panel. That is why access-panel locations and inaccessible sections belong in the work scope.
The duct is not ordinary air-conditioning ductwork. Grease-exhaust systems have specific fire and access considerations. Do not cut new openings or send untrained staff inside. Refer design, access and fire-rating questions to qualified people and the authority requirements that apply to the building.
Exhaust Fan: The Part That Creates Air Movement
The exhaust fan pulls contaminated air through the hood, filters and duct, then discharges it outside. Depending on the system, it may sit on a roof, wall or plant area.
Grease can build on accessible fan parts and inside the housing. It may affect balance, create vibration or leak into a collection area. A new noise does not prove grease is the only cause; belts, bearings, motors or loose parts may need mechanical attention.
Fan work also introduces electrical, moving-part and access risks. Safe isolation and qualified access must be agreed before opening or cleaning the assembly.
Make-Up Air: The Air That Replaces What the Fan Removes
An exhaust fan removes a large volume of air from the kitchen. Make-up air replaces it. If the balance is wrong, doors may become hard to open, outside air may rush through gaps, and the hood may struggle to capture smoke.
A dirty hood is not the only explanation for weak capture. Building ventilation settings, blocked supply points or changes to the kitchen can alter air movement. If cleaning does not correct smoke escape, ask for airflow and mechanical checks rather than repeating surface work.
Grease Cups and Collection Points
Filters and fans may drain residue into cups, trays or other collection points. These small parts can overflow if they are ignored. The daily or weekly site checklist should name who checks them and how waste is handled.
Grease outside the collection point may signal overflow, poor fitting or a leak. Take a photograph and trace the source safely instead of treating the surrounding stain as the whole problem.
Fire-Suppression Equipment Is a Separate System
Many commercial cooking lines have fire-suppression equipment linked to the hood. Nozzle caps, piping, detectors and controls may sit near areas being cleaned, but cleaning them is not the same as servicing or certifying the fire-protection system.
The hood-cleaning scope should state how nearby fire-system parts will be protected and who is authorised to isolate, inspect or restore them. Dubai Civil Defence publishes the UAE Fire and Life Safety Code of Practice, which should be used with current site-specific directions.
Match the Cleaning Scope to the Component
- Before booking, list what is included:
- Visible hood canopy and channels
- Removable grease filters
- Accessible plenum surfaces
- Accessible duct sections and panels
- Exhaust fan and housing
- Grease cups or collection areas
- Protection and handover of nearby surfaces
- Photographs and restricted-access notes
The commercial kitchen exhaust maintenance guide gives a practical routine for connecting staff checks with professional visits. If the system needs a site assessment, Clean Well offers kitchen hood cleaning in Dubai for restaurant hoods, accessible ducts and exhaust components.
Frequently Asked Questions
Is a kitchen hood the same as an exhaust fan?
No. The hood captures the cooking plume above the equipment. The fan creates the pull that moves air through the filters and duct. They are connected parts with different functions.
What is the purpose of a commercial hood filter?
It captures part of the grease carried in cooking vapour before that grease travels into the plenum and duct. It must fit correctly and be cleaned or replaced according to its condition and maker’s instructions.
Does hood cleaning automatically include the duct?
Not always. “Hood cleaning” can be used loosely. Ask for a written scope that names the canopy, filters, plenum, duct sections, fan and collection points included in the price.
Where does grease collect in an exhaust system?
It can collect on the canopy, filters, plenum, duct walls, access-panel edges, fan parts and grease cups. The pattern depends on cooking load, airflow, filter condition and system layout.
Can commercial hood filters be cleaned instead of replaced?
Some reusable filters can be cleaned, while damaged or non-reusable products need replacement. Follow the filter manufacturer’s instructions and do not reinstall a bent, broken or poorly fitting filter.
