When choosing a new cooker hood, most people look at design, noise level and extraction performance. One value on the energy label is often overlooked: the grease filtering class of the cooker hood. It reveals how much grease the filter actually holds back and thus helps determine whether a film of grease settles on cupboards, in the extract duct or in an activated carbon filter. In catering, the topic plays an even greater role, because fire protection is also at stake there.
In this guide, we explain what grease filtering classes A to G mean, which filter types exist and how hoods in commercial kitchens are assessed under DIN EN 16282-6. We also show how to care for grease filters properly so that separation is maintained in everyday use. As of: October 2026.
What the grease filtering class of a cooker hood tells you
Since 2015, domestic cooker hoods have carried an EU energy label under Regulation (EU) No 65/2014. In addition to the energy efficiency class and annual electricity consumption, it shows the fluid dynamic efficiency, i.e. how well the fan converts electricity into air movement, the lighting efficiency, the sound power level and the grease filtering efficiency as a class from A to G.
Grease filtering efficiency states as a percentage how much of the grease released during cooking is retained in the filter. It is determined in the laboratory using a standardised test procedure with a clean filter. Whatever the filter does not separate is deposited in the housing, the fan and the extract duct. With recirculation hoods, it reaches the downstream activated carbon filter, which clogs and then binds odours less effectively. A switch to the new energy label has been announced for hoods, but no binding date had been set at last report.
Grease filtering classes A to G at a glance
The following table shows the classes with the corresponding ranges of grease filtering efficiency as used on the EU label. The values are rounded.
| Grease filtering class | Grease filtering efficiency | Rating |
|---|---|---|
| A | over 95 % | very good |
| B | around 85 to 95 % | good |
| C | around 75 to 85 % | average |
| D | around 65 to 75 % | moderate |
| E to G | below 65 % | weak |
For an extract solution in a kitchen where frying is a regular occurrence, a hood in class A or B is advisable. With recirculation, a high class pays off twice over because it extends the service life of the activated carbon. Bear in mind, however, that the class describes a laboratory value. In everyday use, separation drops when the filter is full, and a hood running at too low a setting does not fully capture the cooking vapours in the first place.
Filter types in the hood: mesh, baffle and perimeter extraction
Multi-layer metal grease filters made of aluminium or stainless steel are widespread in domestic hoods. The air flows through several layers of expanded metal, and grease droplets cling to the fins. Cassette filters with deflector plates, also called baffle filters, on the other hand force the air into tight bends. The heavy grease droplets cannot follow the flow, hit the plate and run off. This design comes from catering and clogs more slowly. With perimeter extraction, the air flows through a narrow gap at the edge of a cover panel, which increases the velocity and improves separation.
All of these filters rely on inertia. They separate large droplets well, but very fine aerosols hardly at all. Measurements in commercial kitchens summarised by the testing institute DMT in a technical information sheet found a mean aerosol diameter of only about 0.5 micrometres when grilling and about 2 micrometres when pan-frying. Odours, in turn, are predominantly gaseous and cannot be retained by grease filters at all. That requires activated carbon; read more in the guide Activated carbon filters against odours.
Commercial kitchens: aerosol separators under DIN EN 16282-6
There is no energy label with grease filtering classes for hoods in commercial kitchens. The relevant standard here is DIN EN 16282-6, which sets out requirements for aerosol separators and has replaced the former DIN 18869-5. Two types are distinguished. Type A separators have passed a flame penetration test: a fire under the hood must not pass through the filter into the extract duct. Type B separators have not been tested or have not passed the test.
Above ranges, fryers, grills and other thermal appliances, only Type A separators are therefore permitted. Type B can at most be considered in areas without heat sources, such as the dishwashing area. You can read details of the requirement in the guide Flame protection filters in commercial kitchens.
Comparing separation performance correctly
For separation performance, VDI 2052 Part 1 describes a method for determining the fractional separation efficiency. It shows how well a separator retains particles of a specific size. Experts advise asking the supplier specifically for this curve instead of settling for a single overall efficiency figure. Pressure loss is just as important, because a separator with very high separation but high resistance needs a more powerful fan.
Cleaning grease filters: maintaining separation performance
A dirty filter separates less effectively and slows down the airflow. Metal grease filters from domestic hoods can usually be cleaned in the dishwasher; the manufacturer specifies the interval in the operating instructions. Many hoods indicate when cleaning is due via a saturation indicator. Aluminium filters may discolour in the dishwasher, but this does not affect their function.
In commercial kitchens, VDI 2052 provides for a daily check of hoods and separators, with cleaning as required, correspondingly often with fryer and grill operation. Large dishwashers or soaking tanks with a grease-dissolving cleaner have proven effective. Afterwards, refit the filters in the intended direction and at the intended angle so that the separated grease runs into the collecting channel. Downstream electrostatic filters are an option for very fine aerosols. An overview of the entire kitchen planning is given in the guide to planning a commercial kitchen.
Which grease filter goes where? Designs compared
You will come across very different grease filters on the market. The following overview classifies the common designs by area of use. The separation performance a specific model achieves and whether it has been tested for flame penetration is stated in the manufacturer's data sheet.
| Filter design | Principle | Typical use |
|---|---|---|
| Multi-layer metal grease filter | Expanded metal in several layers | Domestic hoods, recirculation hoods upstream of activated carbon |
| Cassette or baffle filter | Deflector plates, grease impacts and drains off | Catering hoods, high-quality domestic hoods |
| Knitted mesh filter | Knitted stainless steel or aluminium wire | Pre-separation, exhaust air cleaning, appliances with a high grease load |
| Type A aerosol separator | Tested for flame penetration under DIN EN 16282-6 | Above ranges, fryers and grills in commercial kitchens |
| Electrostatic filter | Electrostatic separation of fine particles | Downstream exhaust air cleaning, reduction of odour and smoke |
A stainless steel knitted mesh filter is easy to clean and is suitable as a pre-stage, for example upstream of activated carbon or an exhaust air cleaning unit. Above thermal appliances in a commercial kitchen, however, only the tested design counts. Whether your business may use recirculation at all depends on the appliances and the menu; read more in the guide Extract air or recirculation in the commercial kitchen.
When buying replacements, pay attention to the correct dimensions and installation position. A filter that does not sit tightly in its frame allows air and grease to flow past the edge. Good separation performance then helps little, because part of the cooking vapour does not pass through the filter at all. Replace deformed or damaged filters instead of continuing to use them.
A simple rule applies to domestic hoods: use replacement filters from the appliance manufacturer or replicas that are expressly suitable. The grease filtering class on the label was determined with the original filter; a different filter can change separation and airflow. In commercial kitchens, only use replacement separators with proof of Type A and file this proof with the system documentation.
Frequently asked questions
Which grease filtering class should a recirculation hood have?
Class A or B is advisable. The more grease the metal filter retains, the longer the activated carbon filter behind it stays absorbent and the less often it needs replacing.
Does the grease filtering class also apply to catering hoods?
No. The EU energy label applies to domestic hoods. In commercial kitchens, what counts is the type under DIN EN 16282-6; Type A is required above thermal appliances.
May I use domestic grease filters in a commercial kitchen?
This is not advisable. Domestic filters are generally not tested for flame penetration and are not designed for the quantities of grease in a commercial kitchen.
Does a new filter improve the grease filtering class?
The class is an appliance value and does not change. However, a clean or new original filter ensures that the hood actually achieves its tested performance in everyday use.
Conclusion
The grease filtering class on the energy label shows how much grease a domestic cooker hood retains in the laboratory. Class A or B protects furniture, extract ducts and activated carbon noticeably better than the lower classes. Different standards apply in commercial kitchens: there, Type A under DIN EN 16282-6 determines use above cooking appliances, supplemented by the fractional separation efficiency. In both cases, only a regularly cleaned filter delivers what the test promises. You will find hoods, separators and exhaust air cleaning for commercial kitchens in our categories Kitchen Extraction and Cooker Hoods, InoxAir and Air Purifiers and Exhaust Air Cleaning.
