Smart hoods can be connected to an appropriate hob and can be controlled by app. Photo: AMK
Combined kitchen/living rooms are on trend. This is where living, cooking and eating merge into one, the architecture is open and the kitchen is the focal point of domestic life. The unfortunate consequence is that less pleasant odours sometimes spread throughout the home, too. Modern ventilation systems can help solve this problem, with the various designs offering different solutions, depending on how our living spaces are designed and what our cooking habits are.
Extraction or recirculation: it’s a question of configuration
During the extraction process, the cooking fumes being sucked out (the steam) are discharged to the outside via an exhaust air duct system together with the odours and moisture. To fit this sort of ventilation system, a hole must be made in the house wall. There is also a need to feed new, fresh air into the kitchen-cum-living room to replace the air that has been removed so that no unacceptable negative pressure is created.
In an air recirculation system, the extracted air is conducted through several filters, stripped of grease and odours and then fed back to the combined kitchen/living room. This design, however, does not remove the moisture generated during cooking. Therefore, when choosing this ventilation system of this kind, there should always be a way of providing additional ventilation, for example through a balcony door or a window near the hob.
Although most fume removal systems are designed to exhaust air to the outside or recirculate air, there are also hybrid models that make it possible to switch operation between recirculation and extraction (in conjunction with a corresponding air duct system and wall box). This way, the advantages of both operating modes can be exploited and, for example, ventilation can be provided by means of the recirculation mode in winter so that the cleaned, warm indoor air remains in the kitchen-cum-living room. In summer or during cooking processes that produce strong odours, it’s then possible to switch over to extraction mode.
Against the laws of physics: downward suction
For those who find “conventional” cooker hoods visually unappealing or who want to use the space for extra storage, there are alternatives in the form of a downdraft extractor – also known as a venting hob or worktop extractor – or a trendy induction hob with an integrated extractor unit. In these downdraft systems, the cooking fumes are extracted downwards contrary to the laws of physics. However, they require a significantly more powerful fan than the hood variants do.
When choosing a downdraft system that recirculates air, it’s recommended that you install an additional, enclosed air duct system in the kitchen base unit. This will direct the filtered air away from the base area and thus prevent moisture damage to furnishings, walls or floor coverings.
Various factors determine efficiency
Modern island hoods can regulate their fan power automatically on request and switch off automatically after cooking. Photo: AMK
The efficiency of an extractor unit that sucks away cooking fumes and removes grease and odours depends on various parameters. On the one hand, you should look at the size and extraction capacity (fan power or extraction rate in m³/h) in relation to the floor area of the kitchen-cum-living room. On the other hand, you should consider how often you cook and with what intensity. The positioning and design of the unit also have an important role to play. So too does the quality of the filters used (metal grease filters, activated carbon filters) and ensuring they are cleaned regularly, according to the respective manufacturer’s recommendations. For example, an activated carbon filter used in an air recirculation hood can be regenerated several times, but it will still need to be replaced at some point.
In view of energy saving, sustainability, environmental awareness and climate protection concerns, it’s also worth considering which ventilation system is best suited for particularly climate-neutral buildings and energy-efficient homes. As a general rule, it’s possible to operate either air recirculation or extraction systems in energy-efficient buildings. The most suitable operating mode in the individual case depends both on the building’s structural conditions and on user behaviour.