Commercial Kitchen Grease Filters: Types, Maintenance, and When to Replace Them
Grease filters are the first component in your kitchen extraction system that airborne grease particles encounter. Their job is to separate grease from the airstream before it enters the ductwork — and when they are working correctly, they significantly reduce the rate of grease accumulation in the duct and fan.
When they are blocked, degraded, or missing, the consequences are serious: grease bypasses the canopy and enters the ductwork directly, accelerating accumulation, increasing fire risk, reducing extraction efficiency, and potentially invalidating your TR19 compliance certificate.
This guide covers the three main types of commercial kitchen grease filter, how to maintain them, and when to replace them.
The Three Main Types of Commercial Kitchen Grease Filter
Baffle Filters
Baffle filters are the most common type of grease filter in commercial kitchens. They work by directing the airstream through a series of angled metal baffles, which cause grease particles to collide with the surfaces and drain into a collection trough.
Construction: Typically stainless steel or aluminium, with multiple layers of angled baffles.
Advantages: Durable, washable, and reusable. High grease separation efficiency. Suitable for most commercial cooking types including frying, grilling, and wok cooking.
Maintenance: Baffle filters should be inspected weekly in high-volume kitchens and cleaned as required — typically weekly or fortnightly in busy operations, monthly in lighter-use kitchens. They can be cleaned in a commercial dishwasher or with a degreasing solution.
Replacement: Baffle filters should be replaced when the baffles become distorted, the frame is damaged, or the filter cannot be cleaned to an acceptable standard. With proper maintenance, a good-quality baffle filter can last several years.
Mesh Grease Filters
Mesh filters use multiple layers of aluminium or stainless steel mesh to capture grease particles. They are typically used in lighter-duty applications or as a secondary filter behind baffle filters.
Construction: Multiple layers of woven metal mesh in a frame.
Advantages: Lightweight and lower cost than baffle filters. Available in a wide range of sizes.
Disadvantages: Lower grease separation efficiency than baffle filters. More prone to blocking in high-volume kitchens. Not suitable for heavy-duty frying or wok cooking.
Maintenance: Mesh filters require more frequent cleaning than baffle filters in equivalent cooking environments. They should be inspected weekly and cleaned as required.
Replacement: Mesh filters should be replaced when the mesh becomes blocked beyond cleaning, the frame is damaged, or the filter is more than 12–18 months old in a high-use kitchen.
Carbon / Charcoal Filters
Carbon filters are used in recirculating extraction systems — systems where the extracted air is cleaned and returned to the kitchen rather than discharged externally. They use activated carbon to absorb cooking odours.
Construction: Activated carbon granules or carbon-impregnated foam in a cartridge.
Advantages: Effective at absorbing cooking odours. Essential for recirculating systems where external discharge is not possible.
Important limitation: Carbon filters must be replaced, not cleaned. Once the activated carbon is saturated, it cannot be regenerated by washing — it must be discarded and replaced with a new cartridge.
Replacement: Carbon filters should be replaced every 3–6 months depending on cooking volume. In high-volume kitchens, replacement may be required more frequently. A saturated carbon filter will allow odours to pass through and may also restrict airflow.
How Filter Condition Affects TR19 Compliance
TR19 (the BESA standard for kitchen extraction system cleaning) does not specify filter replacement intervals directly, but it does require that the extraction system is maintained in a condition that prevents grease accumulation in the ductwork.
A blocked or degraded grease filter that allows grease to bypass the canopy and enter the ductwork will cause the ductwork to accumulate grease faster than the TR19 cleaning schedule anticipates. This can result in grease deposit levels exceeding the TR19 limit of 200 microns before the next scheduled clean — which means the system is non-compliant between cleans.
During a TR19 clean, your contractor should inspect the condition of your grease filters and note any deficiencies in the post-clean report. If filters are severely degraded or missing, this should be flagged as a recommendation for remediation.
Recommended Maintenance Schedule
The following table provides indicative maintenance frequencies based on cooking volume. Your specific requirements may vary depending on the type of cooking carried out.
- Cooking Volume — Filter Inspection — Filter Cleaning — Filter Replacement
- --- — --- — --- — ---
- Light (café, sandwich bar) — Monthly — Monthly — Annually
- Moderate (restaurant, pub kitchen) — Weekly — Fortnightly — Every 12–18 months
- Heavy (high-volume restaurant, hotel kitchen) — Weekly — Weekly — Every 6–12 months
- Very heavy (fast food, wok cooking) — Daily — Weekly — Every 3–6 months
These are indicative frequencies only. Your cleaning contractor should assess your specific system and cooking patterns and recommend an appropriate schedule.
Signs That Your Filters Need Replacing
In addition to following a maintenance schedule, watch for these signs that your filters may need replacing:
- Visible damage: Distorted baffles, damaged frames, torn mesh, or corrosion
- Persistent grease after cleaning: If filters cannot be cleaned to an acceptable standard, they should be replaced
- Reduced extraction efficiency: If your kitchen feels smokier or more humid than usual, blocked filters may be restricting airflow
- Increased grease in the ductwork: If your TR19 cleaning contractor reports faster-than-expected grease accumulation in the ductwork, filter condition may be a contributing factor
- Age: Even well-maintained filters have a finite service life. If your filters are more than 2–3 years old, have them inspected by a professional
Supply and Fitting
BlueTick Extraction Hygiene supplies and fits commercial-grade grease filters across Peterborough, Cambridgeshire, Northamptonshire, and Lincolnshire. We supply:
- Baffle filters in standard and custom sizes
- Mesh grease filters in standard and custom sizes
- Carbon filter cartridges for recirculating systems
All filters are commercial-grade and sourced from approved UK manufacturers. We can supply filters as a standalone service or as part of a scheduled TR19 cleaning contract.
Filter pricing:
- Baffle filters: £25 – £65 each (supply and fitting, excluding VAT)
- Mesh filters: £15 – £40 each (supply and fitting, excluding VAT)
- Carbon cartridges: £30 – £95 each (supply and fitting, excluding VAT)
To arrange a free site survey and filter assessment, call us on 07840 992 246 or complete our online enquiry form.