Charcoal filters, carbon filters, grease filters, vented extraction, recirculating extraction. It’s easy to see why some clients get a little confused around cooker hoods and what they need for their particular setup.

A question I’m often getting asked is, do I need a charcoal filter for my cooker hood?

In this post, I’ll explain what a charcoal filter is, if and when you need one as well as answer some frequently asked questions I get around the topic.

Let’s get into it!

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What Is A Charcoal Filter (Cooker Hood)?

A charcoal filter is an additional filter that can be installed into most modern-day cooker hoods. They come in various shapes and sizes to fit the various cooker hood types and manufacturers models and are designed to help remove unwanted smells in your kitchen caused by cooking.

They have a black mesh appearance and can be a single layer, multiple layers and even constructed in a honeycomb structure. This is all the maximise the surface area available. Which is important to how effective they are and how long they can last.

The filters contain activated charcoal scattered throughout the black mesh filters. These charcoal particles are incredibly effective at adsorption. This is when anything organic (such as the oils from cooking) that comes into contact with the charcoal will get stuck and held by it.

That means you won’t get those bad smells blowing around your kitchen. So, the bigger the charcoal filter, or the bigger the surface area of the filter, the more smells can get trapped and the longer it will last before becoming completely saturated. Once that happens you’ll need to replace the charcoal filter.

Are Charcoal And Carbon Cooker Hood Filters The Same?

Yes. Charcoal and carbon filters (sometimes called active carbon or active charcoal filters) are the same thing when it comes to cooker hoods. It’s just that different manufacturers call them by these different names. Which can cause a little confusion.

However, they perform the same task when it comes to cooker hood filtration.

Do I Need A Charcoal Filter For My Cooker Hood?

You should always install charcoal filters when your cooker hood is recirculating the air (recirculation mode) and not venting to the outside. If the cooker hood is installed using a vented extraction system, you do not need charcoal filters.

Charcoal filters are there to adsorb the bad smells created during cooking. Your cooker hood will suck in the air which contains grease and oils (the source of the smells) and draw them through the charcoal filter. The filter will then trap any oils in place, thus removing them from the air which will then get recirculated back into your room.

Without the charcoal filters, there is nothing to trap these oils and smells. So the air containing them will simply get blown back into your kitchen and won’t be effective at removing unwanted smells.

However, if your cooker hood is installed to vent to the outside, you don’t need a charcoal filter. There is no need to filter this air of smells as it won’t get blown back into the room. It gets blown along a vent and outside the house completely.

How Often Should You Change A Charcoal Filter In A Cooker Hood?

A good general guide is that charcoal filters should be replaced every 3-9 months.

However, this will depend on how often you cook and use the cooker hood, the style of cooking you do as well as how big the filter is or to be more precise, how much surface area the filter has. As that will determine how many active charcoal particles it can hold, and how much it can adsorb.

Some filters are designed to have more surface area and can perform for longer. Check the type of filter specific to your cooker hood to see what the manufacturer recommends.

Can Charcoal Filters Be Cleaned And Reused?

No, unfortunately not. Standard charcoal filters will eventually stop working and cannot be cleaned or reused.

This is because the filter becomes full of all the impurities that it has adsorbed. Once that happens, the air being drawn up by your cooker hood no longer gets cleaned of smells and will blow the ‘smelly’ air back into the room. You cannot wash a standard charcoal filter to clean it either.

The only way to clean a standard charcoal filter is to activate the charcoal again by heating it over 900 degrees celsius. This then releases any particles trapped by the charcoal. This process can cause toxic gases to get released, so definitely not a good scientific experiment for your home. Just get a new filter.

Long Life Carbon Filters

However, there are such things as long life carbon filters. These are a particular type of carbon (charcoal) filter that can be cleaned and reused. Depending on how much they get used you can generally wash and restore them 4-8 times before they will need to be replaced.

Simply rinse them under hot water, without using a sponge or any soap. Once drained, place the filter in an oven at 60°C for about 7 minutes. Until the filter has fully dried out. Once cool you can then put it back in the cooker hood.

What Is The Difference Between A Grease Filter And A Charcoal Filter?

A grease filter is fitted as standard to every cooker hood and helps to trap grease particles generated while cooking. It has a metal mesh construction that the grease sticks to (image below) and is usually exposed on the underside of your cooker hood directly above your hob.

Grease filters are used on all cooker hoods regardless of whether they are vented to the outside or in recirculating mode. They are designed to help prevent grease from entering the cooker hood or getting blown around your kitchen.

A key difference is that grease filters do not contain any active charcoal so don’t trap oils and smells in the same way charcoal filters do.

Can Grease Filters Be Cleaned And Reused?

Yes. Unlike a standard charcoal filter, you can clean and re-use your grease filters.

People often forget to clean their grease filters but it is a task that should be done to maintain the optimal performance of your cooker hood. Plus, it can be much easier than you think. Most grease filters are on simple clips on the underside of the cooker hood. Simply unclip and remove them, then give them a soak and wash or even put them in the dishwasher (always check that they’re dishwasher safe first).

How Often Should You Clean A Grease Filter In A Cooker Hood?

This will depend somewhat on your style of cooking and how often you actually cook. A good general rule is every 2-6 months.

If you do a lot of cooking involving frying which releases more grease into the air, then maybe up that to 1-3 months. However, f you barely use the hob and cooker hood, then you’ll probably be fine with 6-12 months. 

If you do not clean your grease filters it will impact the performance of your cooker hood. It may lead to increased noise levels and can be a fire safety hazard.

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Final Thoughts…

There you have it! Everything you need to know about charcoal filters for your cooker hood.

In short, if you’re having a cooker hood in recirculation mode then you should purchase some charcoal filters to get the best performance out of the appliance and keep your kitchen as clean and smell-free as possible. If your cooker hood is being vented to the outside, you don’t need to worry about them.

I hope this guide has helped clear up any confusion around charcoal filters for your cooker hood and best practices around them. Happy cooking!

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