Extractor Hood Filters, What Are They And Which Filter Do You Need?

The filters for extractor hoods are possibly the most important element of our hoods, since the retention of fat and the annoyance of smells and fumes in the kitchen depend on it, a bad extraction can even generate annoying smells in the dining room.

This last point is very important in a commercial restaurant as no customer would like to go out with “food smell” on their clothes after eating.

The most common filters for extractor hoods

• Stainless Steel Slatted Filter: These filters have become widespread in cooker hoods for two main reasons “Aesthetics” (they are eye-catching and have an attractive design) and practice (they are very easy to clean even in a normal kitchen sink).

This type of filter for extractor hoods causes a kind of centrifugation inside it that throws the grease particles against the tubular walls of the filter, retaining them and draining them towards the bottom of the filter.

Although it is not considered very important by hood installers, this filter increases the efficiency at a certain air passage through the slats, decreasing its effectiveness when the passage through the slats is very fast, above 1.5 m/s. The efficiency of these filters does not usually exceed 60%.

• ECO stainless steel slat filter: These filters, although aesthetically similar to the previous ones, are usually made with half moons and incorporate a metallic mesh or screen to capture the grease particles that the half moons cannot capture. These filters have a very low efficiency in the capture of oils (less than 30%).

• Mesh Filter: Usually manufactured in two versions stainless and galvanized (or a mixture of the two) is a sandwich of several layers of mesh in a zig-zag or double zig-zag, is manufactured in two widths 25 and 50mm. This type of filter is called a condensation filter. 

The oil particles pass through the different meshes condensing on the wires and draining towards the bottom of the filter, this type of filter has a very high efficiency with an efficiency in some manufacturers above 70%.

• Combined Filters: These filters combine a louver filter on the outside and a mesh filter on the inside so that a double filtering is produced with an efficiency of more than 90%. It is rare to find them since in the times we live in the tendency is to invest as little as possible in what is not seen.

• Activated Carbon Filters: These filters are used to eliminate odors from filtered fumes by the chemical reaction of activated carbon with the odor particles. It is important to combine them with a mesh filter on the outside that eliminates the oil as much as possible, since the oil saturates the filter and makes it inactive. 

There are two qualities: the “blanket” filter, which is more cost-effective and less efficient, and the “granules or grain” filter, which is made up of small balls of active carbon inside a mesh that acts as a support. These filters cannot be cleaned or regenerated and have to be changed once they are no longer effective.

• Electrostatic Purification Filters: Unlike the previous ones that are inserted in the hood itself, these filters are installed in the ductwork, if possible at more than 26 feet from the hood or heat source so that the air that passes through them is as cold as possible. Their mission is to eliminate fumes and odors.

It is usually equipped with a triple filter Mesh (filters coarse particles), Electrostatic (fine particles) and activated carbon (odors), in combination with a hood equipped if possible with mesh filters allows to make installations of hoods without the need for duct to the roof.

• Ozone filters: They are used in combination with electrostatic purifiers for the total elimination of odors, although really are more than filters are ozone injectors. 

these injectors need a minimum duct section of 8 meters to effectively perform the oxidation of odor particles, a point, the duct must be stainless steel, as the galvanized steel is corroded by ozone in a very short time.

Do all cooker hoods need filters?

All the hoods need a filter depending on their connection, the hoods need filters of different types:

• Metallic filter: Made of aluminium mesh or it can also be made of stainless steel. This is the anti-grease filter, which is incorporated as standard in all the hoods.

• Activated carbon filter: This is a filter that serves to clean the air by capturing the odors on a porous surface (it absorbs the grease, the vapor and the odors), so that it filters the dirty air and returns it to the kitchen already renewed, it has a limited lifespan and is easy to dispose of. 

it is very easy to apply. It can be installed in the vast majority of cooker hoods without an outlet and is sold separately from the cooker hood.

Which hood filter should you choose for your kitchen?

There are many possibilities to equip the hood with different types of filters for extractor hoods, sometimes you have to analyze the convenience of one or another, depending on the type of use.

for example, if in your kitchen you make a lot of fried food the ideal would be a mesh filter, however if you make a lot of pouting the one with stainless slats will favor the extraction.

Also, when choosing a filter for an extractor hood, you should take into account that the grease that does not remain in the filter ends up in the motor fan, the motor of the ventilation box, ducts, etc. 

This grease ends up damaging the mechanical elements of the extraction box and the grease in the ducts needs to be cleaned, as it can cause accidents due to grease ignition, so it is better to choose a proper filter than to pay for expensive cleaning maintenance.

How long do cooker hood filters last?

Like all filters, the filters of the hoods have to be renewed every few years, always according to the frequency with which the kitchen is used. 

For normal operation (between one and two hours a day) it is advisable to change the filter once a year. There are modern models of cooker hoods that have an indicator that warns when the filter is blocked and you should clean or change it.

How do you change a extractor hood filter?

• Most filters have a very simple fixing system to be easily removed from the bottom of the cover, the first thing is to open the blockage and to fold down the metal anti-grease filter. Grasp it underneath with the other hand and pull it out of the holder.

• In the case of perimeter suction filters, pull the metal anti-grease filter down and grasp it underneath with the other hand.

• In the case of additional filters on the inside, the lock must be opened and the metal anti-grease filter must be folded down. Grip the filter underneath with the other hand.