Extractor Fan Legality: Do You Need One in Your Kitchen?

If you’re sweating it out over whether you need an extractor fan in your kitchen, you’re not alone. The rules confuse just about everyone, even some builders. A lot of folks assume it’s all about keeping cooking smells out, but there’s actually legal stuff to think about too.

Building regs in the UK require any new kitchen or major renovation (like that full-on makeover you’ve been dreaming about) to have 'adequate ventilation'. Seems basic, right? But here’s the thing: how you achieve that ventilation can change depending on your setup. If your kitchen doesn’t have a window or any kind of direct outdoor air flow, you’re almost certainly going to need a proper extractor fan to tick the compliance box. Got a big window you can fling open? That might just get you off the hook.

So, before you Google the fanciest extractor fan on the market or start panicking about breaking the law, keep reading. The details depend a lot on your kitchen’s age, layout, and what sort of work you’re doing. Plus, knowing the smartest way to stay legal could save you hassle — and money — in the long run.

• UK Law: What the Rules Actually Say
• Kitchens That Must Have an Extractor Fan
• Alternative Ventilation Options
• Common Mistakes and How to Dodge Them
• Handy Tips for Easy Compliance

UK Law: What the Rules Actually Say

If you’re dealing with kitchen upgrades or planning a remodel, it pays to know what the rules actually demand. The most important rules sit in the Building Regulations Approved Document F, updated in 2021. It’s not the most gripping read, but if you want your project signed off by Building Control—or just want to avoid future headaches—you should know the basics.

The law comes down to this: every kitchen in a new build, or any kitchen getting major changes, needs what the law calls “adequate means of ventilation.” The point isn’t just about smells; it’s about clearing out excess moisture, steam, and cooking contaminants so you don’t end up with mould and a stuffy house.

For most kitchens, this means a mechanical extractor fan is needed, especially if there’s no window or external wall vent. Regulations say the fan must pull at least 30 litres per second if it’s installed above a hob, or 60 litres per second elsewhere in the kitchen. And yes, the airflow rate matters—inspectors sometimes check! The fan has to vent directly outdoors, not just recirculate air back into the room. Recirculation fans (the kind with filters but no ducting) don’t meet full legal standards for extractor fan requirements in these situations.

• New builds or full refurbishments: Must-have extractor—no shortcuts.
• Kitchen in an open-plan space: Still need a dedicated extractor for the kitchen area.
• No window? Extractor is non-negotiable.

But here’s where it gets a bit grey: if your kitchen is untouched in terms of layout or structure (like you’re just swapping appliances), you might not be forced to add an extractor—though it’s still smart in the long run.

Take a look at the basic requirements for kitchens under current rules:

Long story short: if you’re upgrading or building from scratch, make sure a compliant extractor fan is on your shopping list. Not sure what your case needs? Check with your local council’s Building Control. They’ll tell you straight if you’re covered or if you need to do more. It’s better to ask than to be told to rip out your new kitchen because the airflow isn’t up to scratch.

Kitchens That Must Have an Extractor Fan

Not every kitchen in the UK has to have an extractor fan by law, but certain setups make it a must. If you’re putting in a new kitchen, converting a garage, or giving your current kitchen a total revamp, Building Regulations say you need proper ventilation. This means you’ll likely need an extractor fan unless your kitchen has serious airflow already built in.

The 2020 update to UK Building Regulations (Approved Document F) spells it out: any kitchen ventilation needs to remove steam, smells, and pollutants effectively. If your kitchen doesn’t have an openable window, or if it’s part of a flat or open-plan space, the regulations are even stricter. Relying on a small window just isn’t good enough for new builds or major remodels anymore.

• In new houses or apartments, extractor fans must be installed if the kitchen is inside (no direct outside windows) or is open plan to other rooms.
• If you’re changing the layout so the kitchen moves away from a window, you’ll need to add a mechanical extractor.
• Extensions that turn old rooms into kitchens generally need fans to handle the extra moisture.
• If you rent out property, the law expects decent ventilation to help tackle damp and mold. Many councils now expect extractor fans as standard in kitchen refurbs.

You might be surprised how much moisture and pollutants a normal kitchen creates. Take a look at some real numbers:

Imagine all of that hanging around in your walls and ceiling—no fun. A good extractor pulls that junk out before it can turn into damp patches or worse, black mould.

If you live in a listed building or historic property, you might have exceptions, but you’ll still need to prove the air can circulate. For everyone else, playing by the rules is way less hassle than dealing with mold or a hassle from your local inspector.

Alternative Ventilation Options

So maybe you’re hoping you don’t have to install a full-on extractor fan. Good news: there are legit alternatives, but not all of them will cut it with the law (especially if you’re getting inspected). Here’s how things break down.

The gold standard for alternative ventilation is a decent-sized window you can actually open. UK building rules say a kitchen needs an opening window or “external door” to qualify. If your window’s at least 1/20th of the floor area of the kitchen (yep, they’ve measured it down to that), you’re probably fine as far as regulations go. For most small kitchens, that means a good standard casement window does the trick.

Trickle vents are another thing you’ll see in modern properties. These are little slots at the top of windows that let a bit of air move in and out even when the window’s closed. They don’t count as the main ventilation unless you combine them with something else, but they’re handy for keeping condensation down.

There’s also passive stack ventilation systems, which basically use a pipe running up through your roof. Warm air rises, escapes naturally, and pulls out the smells and steam with it. It’s quiet and there are no moving parts—great for those who hate noisy fans—but it’s not common in standard homes and can be a hassle if you haven’t got space in your roof.

If you live in a flat or anywhere you can’t easily add an extractor, recirculating cooker hoods might pop up as an option. These use charcoal filters to suck in air over the hob, clean it, and spit it back out. Thing is, they don’t actually get rid of moisture, only smells and grease. So, if fighting damp is part of your goal, don’t rely on recirculating hoods alone.

• Openable windows (must be at least 1/20th of the floor area for new builds or conversions)
• Passive stack ventilation (pipe to roof—no fan needed)
• Trickle vents (extra help, not a main option)
• External doors (as main ventilation in some layouts)
• Recirculating cooker hoods (for smell and grease, not moisture)

Just so you know, about 77% of UK kitchens in new builds still install a fan even when a window is there—mostly because it keeps landlords, inspectors, and future buyers happy.

Bottom line: unless your kitchen is tiny, has a good-sized window, or you’re doing just a minor refurb, skipping a proper fan can make life tricky down the road. Knowing your options means you won’t get caught short—or accidentally break the rules.

Common Mistakes and How to Dodge Them

Folks mess up kitchen ventilation more than you’d think. Most issues come from misunderstanding the rules, trying to skip steps to save cash, or just ignoring stuff until it’s a real headache later. Here’s where people slip up most and what you actually want to do instead.

• Extractor fan not venting outside: Loads of people install fans that just recirculate air back into the kitchen. Feels easier at first, but it doesn’t shift moisture or grease properly. Building inspectors usually want ducted fans that send air out, especially if the kitchen is internal with no direct window.
• Not checking local council rules: The UK building regs are national, but some councils have their own quirks. Always double-check or your installation could get rejected during inspection.
• Installing too small a fan: There’s a minimum extraction rate—60 litres per second for mechanical fans near cookers, or 30 litres per second elsewhere (says Approved Document F). Grab the wrong spec and you might as well have thrown your money out the window.
• Skipping maintenance: Even the flashiest fan struggles if it’s gummed up with grease and dust. Dirty filters and blocked vents mean poor airflow and, yep, failure during inspection.
• Ignoring noise levels: Choose a fan that’s too noisy and you’ll stop using it. No one wants a kitchen that sounds like a plane taking off every dinner time.

If you want zero stress at inspection and a kitchen that doesn’t turn into a steam room, start by reading the packaging. Make sure your fan is ducted and hits the required extraction rate. Clean or swap filters every few months, especially if you cook a lot of curries or fry-ups. Ask your installer to double-check with local authorities before fitting anything. Sometimes it’s the small stuff—like buying a quieter model or wiping down the cover regularly—that saves you the most hassle.

Handy Tips for Easy Compliance

Staying on the right side of kitchen ventilation laws isn’t as tough as it sounds. If you want to keep things simple, here’s what actually works in real homes.

• The golden rule: Make sure your kitchen can clear out moisture, odours, and grease. That’s the heart of all extractor fan requirements under UK Building Regulations (specifically Part F, if you want to look it up).
• If you’re putting in a new kitchen or making major changes, always use a fan that can move at least 30 litres of air per second above your hob (or 60 if placed elsewhere). These numbers aren’t random; they’re the minimum legal specs.
• Already have a window? You can sometimes skip an extractor fan for minor repairs or in non-rental homes, but that window needs to open wide and easily. If it’s painted shut or tiny, don’t chance it — just install a fan.
• For rentals, landlords almost always need a working extractor no matter what, thanks to HMO and local rental rules. A broken fan can lead to fines.
• When picking an extractor, look for one with a high enough extraction rate (measured in cubic metres per hour or litres per second). Cheap ones may not cut it, and you could fail an inspection down the line.
• Place the fan close to where you cook for the best airflow. Corner units or installing above the hob usually give the best results.
• Regular cleaning makes a difference. Greasy filters can slow down even a top-range fan, so wash or swap them out every couple of months.

If you’re ever in doubt, ask your builder to show you the exact airflow stats in the spec sheet before fitting a fan. No one wants a surprise snag right when you’re ready to show off your shiny new kitchen.