Anyone opening or refurbishing a restaurant, snack bar or canteen faces an early question: extract air or recirculation in the commercial kitchen? Recirculation solutions look attractive at first glance because no duct through the building and no opening in the roof are needed. But commercial kitchens are held to different standards than domestic ones, and poor planning risks trouble with the authorities, the employers' liability insurance association or the neighbours.
In this guide, we explain the difference between extract air and recirculation, which rules apply to commercial kitchens and why gas appliances play a special role. We also show in which exceptional cases recirculation is conceivable and what to look out for when planning an extract system. As of: October 2026.
Extract air and recirculation in the commercial kitchen: the difference
With an extract system, the hood captures the cooking vapours, the mixture of steam, grease, smoke and odours. Aerosol separators in the hood hold back part of the grease, after which a fan conveys the air through a duct to the outside. Fresh supply air flows in to replace it, ideally via a dedicated supply air system.
A recirculation solution also extracts the vapours, cleans them via grease filters, fine filters and usually activated carbon and blows them back into the kitchen. The problem: filters can bind grease and some of the odours, but they remove neither heat nor moisture. These very loads are enormous in a commercial kitchen with ranges, fryers, combi steamers and a dishwasher. With pure recirculation, temperature and humidity quickly rise to levels that are a strain on staff and encourage condensation on ceilings and walls.
| Feature | Extract air | Recirculation |
|---|---|---|
| Heat and moisture | are removed to the outside | remain in the room |
| Grease and odour | separated and removed | only filtered, filters become saturated |
| Combustion gases from gas appliances | are removed with the air | not permitted without flue gas removal |
| Construction effort | duct, exhaust air, supply air required | low |
What the rules say: VDI 2052 and DIN EN 16282
The state of the art for ventilating commercial kitchens is described above all by the guideline VDI 2052 and the European standard series DIN EN 16282. VDI 2052 applies to commercial kitchens in which the appliances emitting heat and moisture have a combined connected load of more than 25 kW. Such kitchens must be equipped with a supply and extract air system. DIN EN 16282-1 sets out the general requirements and the calculation of air volumes. A revised edition was published in September 2026, replacing the 2017 version.
What the 2026 edition of DIN EN 16282-1 changes
According to manufacturers' technical articles on the new edition, the preliminary sizing distinguishes between kitchen types in more detail, the simultaneity factor is based more closely on the appliances actually used at the same time, and the values for heat and moisture output of the appliances have been updated. A further new requirement is that supply air introduced directly into the kitchen must not cause additional uncontrolled condensation. The German guideline VDI 2052 remains in place alongside it. For operators this means: an existing system does not automatically become non-compliant because of the new edition, but for new builds and conversions the specialist planner should calculate according to the current state.
For smaller kitchens below 25 kW, an extract system is also recommended and, according to a widespread interpretation of the standard, required. For hygiene reasons, pure recirculation is considered acceptable at most for cold kitchens or very limited hot food preparation. Occupational safety and food hygiene come on top of this: under the German Workplace Ordinance, sufficient breathable air that is safe for health must be available at the workplace, and the EU Hygiene Regulation 852/2004 requires sufficient and appropriate ventilation.
What can be approved in an individual case is decided by the building authority, food inspection and, where applicable, the employers' liability insurance association. You should therefore agree your ventilation concept with a specialist planner and the responsible bodies before buying the appliances.
Gas appliances: no gas without running extraction
The situation is particularly clear with gas appliances. Many commercial gas ranges, bratt pans and fryers release their flue gases directly into the room, and the kitchen extract then carries them outside. For such appliances, the DVGW worksheet G 631 requires a safety interlock: the gas supply may only be released when the kitchen ventilation is running. In practice, a flow or pressure monitor supervises the extract air flow and closes the gas valve if it fails.
A recirculation hood cannot perform this task, because carbon monoxide, carbon dioxide and nitrogen oxides cannot be filtered out. Anyone cooking with gas therefore cannot avoid a genuine extract system.
When recirculation is conceivable in catering
There are concepts in which recirculation systems can make sense. These include cold kitchens such as sushi or salad bars, areas in which food is only regenerated or kept warm, and small front cooking stations with electric or induction appliances. High-quality recirculation systems work in several stages with grease separator, fine filter and activated carbon, sometimes supplemented by UV technology.
Two points remain important. First, the room ventilation must still remove the heat and moisture, so recirculation does not replace basic ventilation. Second, the filters need consistent care: saturated activated carbon no longer holds back any odour. How long activated carbon works and when it needs replacing is explained in the guide Activated carbon filters against odours.
Planning an extract system: hoods, supply air and exhaust air
The hood should project beyond the cooking appliances on all sides so that it fully captures the rising vapours. Flame-arresting aerosol separators belong above ranges, fryers and grills; you can read more in the guide Flame protection filters in commercial kitchens. The extract ducts must be airtight and cleanable via inspection openings, because grease deposits in ducts are a considerable fire risk.
Supply air is just as important. Every cubic metre that is extracted has to be replaced. Without a supply air system, negative pressure builds up: doors are hard to open, there are draughts and the hood captures less effectively. It is common practice to bring in slightly less supply air than extract air so that the kitchen is at a slight negative pressure relative to the dining room and odours do not drift into the guest area.
The exhaust air is usually discharged above the roof. If this is not possible or neighbours complain, exhaust air cleaning with an electrostatic filter, UV technology, ozone or activated carbon can significantly reduce grease and odours before discharge. This is still an extract system, not recirculation. An overall overview of the planning is given in the guide to planning a commercial kitchen.
Extract air or recirculation: a decision aid by kitchen concept
Which solution suits your business depends less on the size of the room than on what is cooked there. The following overview summarises the usual classification. It does not replace planning, but it helps you prepare well for the discussion with the specialist planner and the authorities.
| Kitchen concept | Typical appliances | Usual solution |
|---|---|---|
| Restaurant, canteen, hotel kitchen | Ranges, bratt pans, fryers, combi steamers | Extract system with supply air, Type A aerosol separators |
| Snack bar with fryer or grill | Fryer, griddle, gas appliances | Extract system, with exhaust air cleaning if needed |
| Café, bake-off shop | Bake-off ovens, coffee machines | Extract air depending on heat load, check recirculation if the load is low |
| Cold kitchen, sushi or salad bar | Refrigeration, few electric appliances | Room ventilation, recirculation conceivable for individual appliances |
| Front cooking station | Induction or electric, small quantities | Multi-stage recirculation system, only after consultation |
For the classic restaurant kitchen this means in practice a hood over the entire cooking line, for example a ceiling hood with flame protection filters above a free-standing cooking block or a wall hood along the cooking line. Ideally, the fan sits outside the grease-laden airflow so that the motor does not become clogged. If odour complaints arise, exhaust air cleaning with an electrostatic filter, UV technology or activated carbon can be retrofitted without giving up the basic principle of extraction.
Also think about operation when deciding. An extract system incurs costs for electricity and for heating the replacement supply air in winter. A recirculation system saves here but requires regular filter changes. Ask for quotations for both variants including the running costs for filters, cleaning and energy before you commit.
Frequently asked questions
May I use a recirculation hood in a small snack bar?
That depends on the menu and the appliances. For a fryer, griddle or gas appliances, recirculation is generally not sufficient. With a few low-output electric appliances, a recirculation system may be possible if the responsible authorities agree.
When do I need a supply air system?
According to VDI 2052, kitchens with a connected load of more than 25 kW for the appliances emitting heat and moisture must be equipped with a supply and extract air system. But even below that, the extracted air must be able to flow back in a controlled way.
Who inspects the ventilation of a commercial kitchen?
Depending on the project, the building authority, food inspection and the employers' liability insurance association are involved, and with gas appliances also the specialist company for the gas installation. A specialist planner brings the requirements together in a ventilation concept.
Is activated carbon enough to deal with odour complaints from neighbours?
Activated carbon can bind odours effectively, but it requires good grease separation upstream, otherwise it clogs quickly. Where loads are high, multi-stage exhaust air cleaning with electrostatic filters and UV technology is often used.
Conclusion
In the commercial kitchen, extract air is the rule and recirculation the exception. Recirculation can filter grease and odours but removes neither heat nor moisture, and for gas appliances it is not an option. It remains conceivable for cold kitchens or small electric stations, always in consultation with the responsible bodies. Anyone planning an extract system should consider the hood, separators, supply air and exhaust air as a complete system. You will find hoods, exhaust air cleaning and duct systems for commercial kitchens in our categories Kitchen Extraction and Cooker Hoods, Air Purifiers and Exhaust Air Cleaning and Ventilation Ducts and Fittings.
