How Often Should Kitchen Extract Systems Be Cleaned?
It is the single most common question we are asked, and the honest answer is: it depends on how hard your kitchen works. How often a kitchen extract system should be cleaned is governed by the TR19® frequency guidance, which ties the interval to daily cooking hours. Clean too rarely and you build a fire risk and a compliance problem; get the interval right and you stay safe, insured and inspection-ready. This guide sets out the frequency table, real-world examples, and exactly what goes wrong if you leave it too long.
What is the recommended kitchen extract cleaning frequency?
TR19® groups kitchens into three usage tiers based on how many hours the cooking line runs each day. The heavier the use, the faster grease accumulates in the ductwork, and the shorter the interval between cleans. If you are new to the standard, start with our guide on what TR19® is and why it matters, then use the table below.
| Usage level | Typical daily cooking hours | Recommended cleaning interval |
|---|---|---|
| Heavy use | 12–16 hours per day | Every 3 months |
| Moderate use | 6–12 hours per day | Every 6 months |
| Light use | 2–6 hours per day | Every 12 months |
These intervals are a starting point, not a hard rule. The type of cooking matters too — high-volume frying and chargrilling produce far more grease than steaming or baking — so two kitchens open the same hours can need very different schedules. A grease-thickness measurement during a survey gives you an interval based on your actual system, not a guess.
Want an interval set from your real grease levels rather than the calendar? Book a kitchen extract clean and survey.
What do these tiers look like in the real world?
The abstract hours make more sense with examples from kitchens we deal with every week:
- Busy takeaway or fast-food outlet (heavy use). Fryers and a grill running from late morning until late at night, often 12–16 hours a day, seven days a week. Grease builds quickly, so a three-monthly clean is typical — sometimes more often for the heaviest fryers.
- High-street café or bistro (moderate use). Breakfast through to early evening service, roughly 6–12 hours of cooking, with a mix of grilling and lighter dishes. A six-monthly clean usually keeps the system within standard.
- School or staff canteen (light use). Cooking concentrated around a lunchtime service, only a few hours a day and often closed in holidays. An annual clean is frequently enough — but only if the cooking really is light; a school running a busy breakfast and after-school club may move into the moderate tier.
The examples show why a blanket "clean once a year" policy is risky: it under-serves heavy users badly and can lull moderate users into non-compliance.
What happens if you don't clean your extract system often enough?
Skipping or stretching the interval is where real trouble starts. The consequences fall into four familiar categories:
- Fire risk. Grease is fuel. A thick, hardened film inside the ductwork can ignite from a flare-up on the line or a fault in the extract fan, and a duct fire spreads fast through the building via the very system meant to remove smoke.
- Invalid insurance. Commercial policies commonly require the extract system to be cleaned to a recognised standard at appropriate intervals. Without dated certificates and photo evidence, an insurer can reduce or refuse a fire claim, leaving you to carry the loss.
- EHO action. Environmental Health Officers can act on a grease-laden, poorly maintained system, and heavy grease deposits also raise wider hygiene and pest concerns that can trigger further scrutiny.
- Failed audits. Franchise, brand and facilities audits increasingly require proof of TR19® cleaning. No paperwork means a failed audit, and for franchised sites that can put the agreement itself at risk.
None of these are hypothetical — they are the everyday reasons businesses call us after an inspection or a near-miss. Cleaning to the right frequency, with certificates on file, avoids all of them.
How do I know which category my kitchen is in?
If you are unsure, do not guess. Count the genuine daily cooking hours, consider the type of cooking, and if you are near a tier boundary, get the grease measured. A free survey will confirm your usage level, recommend an interval and set up a schedule so cleaning happens automatically before grease reaches a risky level — rather than being remembered only after a problem appears.
Is once a year enough for a kitchen extract clean?
Only for genuinely light-use kitchens cooking 2–6 hours a day. Moderate-use kitchens need cleaning around every six months, and heavy-use kitchens roughly every three months.
Does the type of cooking change how often I need to clean?
Yes. High-volume frying and chargrilling produce far more grease than baking or steaming, so heavy-grease kitchens may need shorter intervals than the hours alone suggest.
What proof do I get that the clean was done to standard?
A dated TR19® certificate with before/after photographs and grease-thickness readings covering the full accessible system — the evidence your insurer, EHO and auditors expect.