Home generalExtractor hood: is exhaust air or circulating air better? | 9 tips

Extractor hood: is exhaust air or circulating air better? | 9 tips

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    • Exhaust air or recirculated air: 9 tips

A kitchen without an extractor hood is unthinkable at the present time. It does not matter whether they convey the vapors produced during cooking to the outside or clean them via air circulation and release them back into the air, without extractor hoods the whole kitchen would stink of fat and other food odors. When installing a fume hood, you must opt ​​for a model with exhaust air or circulating air.


Exhaust air or recirculated air are the typical terms that you will encounter when choosing a new extractor hood. At first glance, this differentiation seems to be simple, but a closer look at the matter makes the decision much more difficult. Each of the two types has its advantages and disadvantages and not every kitchen supports the possibility of installing an exhaust hood.

Here it is important to compare both variants and decide based on your initial situation, which of the two types fits and is worthwhile in the first place. With appropriate tips on this topic, you will find it much easier to choose the right hood in your kitchen.


First of all, you must first be aware of the direct difference between the terms exhaust air and recirculated air, as these determine the function of the steam outlet .

The recirculation variant works in the following way:

  • Vapors are sucked off via the fan
  • In doing so, the air is purified via contained filters (eg grease filter)
  • purified air will give off to ambient air

Accordingly, the air circulates in the room, while the fat contained in the vapor hangs in the filters. In the case of the exhaust hood, on the other hand, after cleaning, the air is led outwards through manholes with a diameter of 125 or 150 millimeters. That's the big difference between the two types of cooker hood. As you already know, these have different advantages and disadvantages, which are discussed in detail below in 9 tips.

Tip: Often it is the case that commercially available extractor hoods are not directly a recirculation or exhaust air variant, but simply the unit that sucks in the air and forwards accordingly. It is therefore purely a form of transmission that either circulates the air inside the room or transports it outside through a shaft.

Exhaust air or recirculated air: 9 tips

The purchase of an extractor hood is important for modern kitchens. To help you with this step, you will find relevant information on the most important points in the following nine tips so that you can integrate the right type of fume hood into your kitchen.


The installation of the extractor hoods is extremely different. The recirculation version has the great advantage that it can be retrofitted without any alterations. Only holes and a power outlet are needed to equip the kitchen with this.

For an exhaust hood, however, exhaust pipes must be let into the wall, which is a big effort. Depending on the thickness of the masonry, the costs can increase significantly, because the wall breakthrough is not really cheap and already alone costs around 200 euros without the installation of the pipes.


The fat is absorbed in both variants via grease filters and thus cleaned the air. This protects against fatty deposits in the kitchen, which rise with the vapors up and could reach the surfaces and walls. Too much grease poses a potential fire hazard, especially if the work surfaces and walls are not cleaned for a long time without an extractor hood.

An exhaust hood conveys significantly more fat from the kitchen, as the smallest of grease remains completely transported out of the building and does not stay in the kitchen if they are not stopped by the filter. The grease filters must be cleaned at regular intervals, which works in the dishwasher. Do not miss this, otherwise the filters become a fire hazard.


If more vapors are routed out of the kitchen and not just cleaned by filters, the odor development during cooking is reduced significantly. An extractor hood with circulating air circulates part of the odor generated during cooking in the room and does not transport it outside. That is why many older apartment buildings often smell intensely of cooked food in the stairwell.

Exhaust air, on the other hand, effectively transports most of the odor outside, thus ensuring a pleasant indoor climate after cooking. Exhaust air is therefore recommended if you prepare very aromatic food with many spices whose aroma would remain in the room for a long time.


If you want to put on a quiet hood, the idea of ​​exhaust or recirculation is also justified. Even if the exhaust hoods are connected via a hole in the wall with the outside world, the noise pollution is clearly limited.

The reason for this is the lack of additional filters that are needed for the operation of a recirculation hood . These hinder the airflow audibly when the hood is in use and may even interfere with the neighbors depending on the model. An extractor hood with exhaust air, on the other hand, draws the fumes exclusively through the grease filter, thereby considerably reducing noise emissions.


Mold growth is a problem which is noticeable especially in circulating air extractor hoods . Since the damp steam is not directed out of the living rooms to the outside, this can settle in walls, furniture and other objects.

If moisture does not escape, mold can form over time, which is not only bad for your health, but can also be costly to clean up. Mold is aggressive and can literally eat into the brickwork if it gets out of control. Mold formation is very difficult with an extractor hood with exhaust air .


As a subtenant, it is necessary to obtain a permit from the property manager or the private landlord, if you want to install an exhaust hood . Since this requires a wall breakthrough, you must clarify with this beforehand, whether this is possible or even meaningful. The installation is not possible in all rented apartments or houses, especially if the basic section of the building is not permitted.

Some landlords will only give you the Ok for the installation if you pay the full cost yourself. You do not have to make that effort with a ventilation hood . For their installation, you should only make sure that there are no cables at the drilling site and that you remove them when you move out.

energy costs

Do not be fooled by the energy efficiency of recirculation hoods . Although these are not so effective, heating costs are significantly reduced over the winter. Since exhaust hoods move heated air out of the living area to the outside, there is an energy loss that has to be compensated.

In this case, you use more energy to make up for the shortfall caused by the use of vapor extraction. If you are careful not to waste too much energy, a hood with circulating air is better for you.

Activated carbon filter

Each extractor with circulating air must have an activated carbon filter. This works in addition to the grease filter active against the vapors, but in a different way. While the grease filter removes grease from the fumes, the activated charcoal filter absorbs unpleasant odors, as the air can not be routed out of the kitchen.

The activated carbon filters are a constant burden on the purse, as they need to be replaced every four to six months. These cost between 20 and 50 euros per piece and the change must be done on your own if you do not want to bear any further costs. Exhaust air hoods do not require an activated carbon filter.


When installing an extractor hood with exhaust air, be sure to use fireplaces in the room, which are also provided with an air outlet. This refers to fireplaces. The reason is the possible poisoning by carbon monoxide (CO) by the pull function of the vapor outlet.

For example, if the fireplace uses real wood, the cooker hood can redirect the smoke back into the room, increasing the concentration of the toxic gas, for example, when the windows are closed or there is no other supply of fresh air. High carbon monoxide pollution can be fatal. Therefore, you should clarify the installation with a chimney sweep .

Based on these tips, it can be said that exhaust air or recirculated air is completely dependent on your living situation, the possible costs and the effort for installation and maintenance. If you are short of cash, a circulating air variant is better than nothing and can be replaced after some time. If you often cook and are a homeowner, a fume extraction hood is definitely much more recommendable, as you can thereby avoid a high odor and noise nuisance .

Tip: Alternatively, you can opt for a cooker hood that supports both functions. These are referred to as switchable and are often installed in energy efficient houses, as the exhaust air function is mainly operated over the summer, while over the winter circulating air is used, which significantly reduces the cost of electricity over the year.

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