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Kitchen extraction cleaning - filters
Kitchen canopy grease filters (baffle or mesh) are designed to be cleaned and reused, not discarded - so the normal answer is to clean them regularly. Replacement is for when a filter is damaged, distorted, corroded or worn out so it no longer does its job. Here is how to tell whether a filter needs cleaning or replacing. This is general guidance.
The short answer
It's a common question: when a grease filter is dirty or worn, do you clean it or replace it? The answer matters both for cost (needless replacement wastes money; keeping a dead filter wastes protection) and for safety (a filter that isn't doing its job lets grease into the ductwork). Here's how to decide. This is general guidance. Filters are made to be cleaned. The starting point: canopy grease filters are designed to be cleaned and reused, not to be disposable. They catch grease from the cooking, and they're built to have that grease removed and go back in - repeatedly. This is especially true of baffle filters (the metal, interlocking-blade type), which are robust and designed to be degreased again and again (in a dishwasher, or by soaking in a degreasing solution) - they last a long time. So the normal, routine treatment of a grease filter is cleaning, not replacement. Regular cleaning keeps the filter working (a clean filter catches grease and lets air through; a clogged one does neither well) and keeps grease out of the ductwork (a grease-laden filter lets grease past). So every filter needs regular degreasing - that's the ongoing upkeep, whatever the filter type (as covered in the filter-cleaning pages). When to replace instead. You replace a grease filter when it's no longer fit to do its job - which comes down to a few conditions: Damaged. Physically damaged - bent or distorted (so it won't sit and seal properly in the housing), split, cracked or holed (so grease passes straight through the gap), or with broken baffles/frame. A damaged filter can't do its job and should be replaced. Corroded or degraded. Rusted, corroded or materially degraded (especially cheaper filters over time) - the filter has deteriorated and won't perform or last. Worn out. A mesh filter, in particular, can clog and mat up over time to the point where it won't come properly clean any more (the grease is embedded in the mesh) - it's worn out and needs replacing. A filter thinned or falling apart is likewise done. Won't come clean. If, after proper cleaning, a filter still won't come clean - it stays clogged or coated - it's reached the end of its useful life and should be replaced. Missing. Obviously, a missing filter must be replaced (never run without them - grease goes straight into the duct). Baffle vs mesh. This is where filter type matters: baffle filters, being durable, are mostly cleaned and only occasionally replaced (when damaged); cheaper mesh filters clog and wear faster and are replaced more often - some treat certain mesh filters as semi-disposable. So the balance of cleaning vs replacing depends partly on what filters you have (as covered in the baffle-vs-mesh page). The practical rule. So the decision is simple in practice: clean routinely (every filter, regularly - the ongoing upkeep), and replace by exception (when a filter is damaged, distorted, corroded, worn out, or won't come properly clean). If a filter is damaged, won't fit or seal, or won't come clean - replace it. Otherwise - clean it. So cleaning is the routine and replacement the exception - and both, done right, keep the filters catching grease and the ductwork protected. So clean regularly; replace when a filter is no longer fit for the job. This is general guidance.
Key points
Made to be cleaned
The starting point for the clean-or-replace question is that canopy grease filters are designed to be cleaned and reused - not thrown away after use. They catch grease from the cooking as the air passes through, and they're built so that grease can be removed and the filter put back to work, over and over. So the default, routine treatment of a grease filter is cleaning, not replacement. This is especially true of baffle filters - the metal type with interlocking blades - which are robust and made to be degreased repeatedly (in a dishwasher or by soaking in degreaser), lasting a long time.
So regular cleaning is the ongoing upkeep of a grease filter, whatever its type. It's what keeps the filter working: a clean filter catches grease and lets air through freely, while a grease-clogged one does neither well (strangling the airflow and letting grease past into the duct). And it's what keeps grease out of the ductwork: a grease-laden filter stops catching and lets grease through to build up in the hidden ductwork, worsening the fire risk. So every filter needs regular degreasing (as covered in the filter-cleaning pages) - that's the routine, and it's not replacement. So made to be cleaned - filters are reusable, not disposable - is the foundation: think cleaning first, replacement by exception. So clean the filters routinely; that's the norm. This is general guidance.
When to replace
You replace a grease filter, rather than clean it, when it's no longer fit to do its job - and that comes down to a few clear conditions. Damaged: physically bent or distorted (so it won't sit and seal properly in the housing, leaving gaps grease bypasses through), split, cracked or holed (grease passing straight through), or with broken baffles or frame. Corroded or degraded: rusted, corroded or materially deteriorated over time (cheaper filters especially) - no longer sound. Worn out: a mesh filter clogged and matted to the point it won't come properly clean any more (grease embedded in the mesh), or a filter thinned and falling apart.
And two more: won't come clean - if, after proper cleaning, a filter still won't come clean (it stays clogged or coated despite a proper degrease), it's reached the end of its useful life and should be replaced; and missing - a missing filter must obviously be replaced (never run the system without filters, or grease goes straight into the ductwork). The common thread is that the filter can no longer catch grease effectively - it can't seal, can't sit right, or can't be got clean - and a filter that isn't doing its job lets grease into the duct (worsening the fire risk), which defeats the point of having it. So when to replace - damaged, distorted, corroded or worn out (or won't come clean, or missing) - is the exception to routine cleaning. So replace a filter that's no longer fit for the job. This is general guidance.
Baffle vs mesh
How often you clean versus replace depends partly on what filters you have, because the two common types behave differently. Baffle filters (metal, interlocking-blade) are durable and designed for repeated degreasing - so they're mostly cleaned and only occasionally replaced, and then usually because they've been damaged (bent, dropped, a broken baffle) rather than worn out. A well-treated baffle filter lasts a long time on cleaning alone. So for baffle filters, cleaning dominates and replacement is rare.
Mesh filters (layers of metal mesh) are cheaper and clog faster, and the grease works into the mesh - so they wear out sooner and won't always come fully clean, meaning they're replaced more often (some operators treat certain mesh filters as semi-disposable, replacing rather than endlessly cleaning). So for mesh filters, replacement comes round more frequently. This is one of the practical differences between the filter types (as covered in the baffle-vs-mesh page) - and a reason many kitchens prefer baffle filters (better cleaning economy and durability). So baffle vs mesh - filter type shifts the balance - means the clean-or-replace answer leans heavily to cleaning for baffle filters, and involves more replacement for mesh. Know which you have, and treat them accordingly. So the filter type affects how often you replace. This is general guidance.
Why a dead filter matters
It's worth being clear why keeping a worn-out filter in service is a false economy - because a filter that isn't doing its job lets grease through to the ductwork. The whole point of the grease filter is to catch grease at the canopy, before it enters the ductwork - so the duct stays cleaner and the fire risk is contained at the filter (which is easy to clean) rather than spread through the hidden duct (which is hard to clean). A damaged, distorted, holed or clogged-beyond-cleaning filter fails at this: grease bypasses it (through gaps, or because it's saturated) and goes into the duct.
So a dead filter doesn't just underperform - it actively lets more grease into the ductwork, accelerating the build-up in the hard-to-reach parts and worsening the duct-fire risk (as covered in why a greasy filter lets grease reach the whole system). That's why keeping a filter that's damaged or won't come clean is a false economy: the small saving on a replacement is paid for many times over in a greasier, higher-risk duct. So when a filter genuinely needs replacing, replace it - the filter's job (protecting the ductwork) is worth far more than the filter's cost. So why a dead filter matters - a poor filter lets grease through - is the reason not to nurse a worn-out filter along. So don't run a filter that's past it; replace it. This is general guidance.
The practical rule
So the practical rule for grease filters is simple: clean routinely, replace by exception. Cleaning is the ongoing upkeep - every filter needs regular degreasing to keep catching grease and to keep grease out of the ductwork, and filters (baffle ones especially) are designed for exactly this. Replacement is the exception - reserved for when a filter is no longer fit to do its job: damaged, distorted, corroded, worn out, won't come properly clean, or missing.
The test in practice: is the filter damaged, or won't it fit or seal, or won't it come clean after a proper degrease? If yes, replace it. If no - it's sound and cleans up - keep cleaning it. Baffle filters will mostly clean up and rarely need replacing; mesh filters wear and get replaced more often. Either way, the aim is the same: filters that are genuinely catching grease and protecting the ductwork - achieved by cleaning them regularly and replacing them when they're spent. Neither over-replace (wasting money on sound filters) nor under-replace (keeping dead filters that let grease through) - just clean the routine, and replace the exception. So the practical rule - clean routinely, replace by exception - keeps the filters working and the system protected, at sensible cost. So clean them regularly, and replace them only when they're done. This is general guidance.
Questions
Clean them - grease filters are designed to be cleaned and reused, so regular degreasing is the normal upkeep; replace only when a filter is damaged, distorted, corroded, worn out, or won't come properly clean. Canopy grease filters (baffle or mesh) are made to be cleaned and put back, not thrown away - so the routine answer is cleaning, done regularly, to keep them catching grease and keep grease out of the ductwork. Baffle filters especially are robust and designed for repeated degreasing. You replace a filter only by exception: when it's physically damaged (bent, split, holed), corroded, worn out (a mesh filter matted beyond cleaning), won't come clean after a proper degrease, or is missing - because then it can't do its job and lets grease through. So the rule is clean routinely, replace by exception. If a filter is damaged, won't seal, or won't come clean - replace it; otherwise clean it. So clean as the norm; replace when the filter is spent. This is general guidance.
Replace it when it's damaged (bent, split, holed), won't fit or seal properly, is corroded or degraded, is worn out, or won't come properly clean after a proper degrease - any of which means it can no longer catch grease effectively. A grease filter needs replacing, rather than cleaning, when it's no longer fit to do its job. The tell-tale signs: it's physically damaged - bent or distorted (so it won't sit and seal in the housing), split, cracked or holed (grease passing through the gap), or with broken baffles/frame; it's corroded, rusted or materially degraded; it's worn out - a mesh filter clogged and matted so grease is embedded and it won't come clean, or a filter thinned and falling apart; or, after a proper clean, it still won't come clean. Any of these means the filter can't catch grease properly and lets it through to the duct. So the test: is it damaged, won't fit or seal, or won't come clean? If so, replace it. Otherwise, cleaning is enough. So replace when it can no longer do its job. This is general guidance.
Baffle filters - they're durable and designed to be degreased repeatedly, so they mostly clean up and rarely need replacing; mesh filters are cheaper but clog and wear faster and won't always come fully clean, so they're replaced more often. The two common filter types behave differently for the clean-or-replace question. Baffle filters (metal, interlocking blades) are robust and made for repeated degreasing (dishwasher or soaking) - they last a long time and are mostly cleaned, only occasionally replaced (usually when physically damaged). So they have good cleaning economy. Mesh filters (layers of metal mesh) are cheaper to buy but clog faster, and grease works into the mesh - so they wear out sooner and won't always come fully clean, meaning more frequent replacement (some are treated as semi-disposable). So baffle filters generally offer better durability and cleaning economy, which is one reason many kitchens prefer them (as covered in the baffle-vs-mesh page). So baffle filters clean and reuse better; mesh filters get replaced more. So baffle filters, for cleaning and reuse. This is general guidance.
No - if a filter won't come properly clean after a proper degrease, it's reached the end of its useful life and should be replaced, because a filter that stays clogged or coated can't catch grease effectively and lets it through to the duct. A grease filter that, despite a proper clean (dishwasher or soak in degreaser), still won't come clean - it stays clogged, coated or matted - is worn out. This happens especially with mesh filters, where grease becomes embedded in the mesh and can't be fully removed. Continuing to run such a filter is a false economy: it can't catch grease properly (it's already saturated), so grease bypasses it into the ductwork, worsening the fire risk - the small saving is paid for in a greasier, higher-risk duct. So a filter that won't come clean should be replaced, not nursed along. The filter's job (protecting the ductwork) is worth far more than the filter's cost. So no - replace a filter that won't come clean. So no; a filter past cleaning is done. This is general guidance.
Grease goes straight into the ductwork - a missing or damaged filter can't catch it, so grease builds up faster in the hidden duct, worsening the fire risk; never run without filters, and replace damaged ones promptly. The grease filter's whole purpose is to catch grease at the canopy, before it enters the ductwork - keeping the duct cleaner and containing the fire risk at the easy-to-clean filter rather than the hard-to-clean hidden duct. If a filter is missing, or damaged (bent, holed, won't seal), it can't do this: grease bypasses it and goes into the ductwork, building up faster in the parts that are difficult and costly to clean, and worsening the duct-fire risk. So running without filters, or with a damaged one, actively harms the system (as covered in why a greasy filter lets grease reach the whole system). Never remove the filters, and replace a damaged filter promptly - the protection they give the ductwork is well worth it. So grease reaches the duct; don't run without sound filters. So it lets grease into the ductwork - never do it. This is general guidance.
Clean them regularly - frequently for heavy or greasy cooking - and yes, regular cleaning extends filter life and reduces replacement, because grease removed promptly doesn't get the chance to embed and wear the filter out. Grease filters need cleaning regularly, at a frequency matched to your cooking: heavy, greasy cooking (frying, grilling) loads the filters fast and needs frequent cleaning (often weekly or more), while lighter cooking loads them more slowly. Regular cleaning keeps the filters catching grease and the airflow free - and it does extend their life: grease removed promptly doesn't get the chance to embed deeply (in mesh) or harden and corrode, so the filters stay cleanable and sound for longer, reducing how often they need replacing. So consistent, frequent-enough cleaning is both the routine upkeep and the way to get the most life from your filters before replacement. Neglected filters, by contrast, clog, embed grease and wear out (or corrode) faster. So clean regularly to keep them working and to reduce replacement. So yes - regular cleaning extends filter life. This is general guidance.
We clean the canopy filters as part of the extraction service - degreasing the reusable filters that keep grease out of your ductwork - and flag any that are damaged, corroded or worn out and need replacing. Ask us to keep your filters catching grease and your ductwork protected. This is general guidance.
