Ventilation filters for range hoods: not all of them filter well

Ventilation filters for range hoods: not all of them filter well

The ventilation principle is used in numerous range hoods. But the easier assembly and the slightly lower initial investment are not everything. That's why it's worth taking a closer look. This is what Naber did as part of a scientific study. One of the results: the plasma filters examined were disappointing across the board.

As a partner of no less than three research institutes (see below), Naber was able to bring its competence in kitchen ventilation to the study. In addition to aspects of energy efficiency, the quality of ventilation systems was also put to the test. As we know, these devices push the drawn-in air through several filters to stop grease and odors before the air is led back into the room.
It was investigated, among other things, how well the activated carbon filters of range hoods with ventilation technology block odors. For this purpose, the concentration of volatile organic compounds (VOC) in front of and behind the filter unit was measured. The values in new filters varied widely. With more than 95 percent of all VOC, Naber's GREENflow filter box removes the most odors from cooking vapor. Several other of the brand filters also achieved a filtering rate of just under 95 percent. Poorer filters remove only about 80 percent of odor-forming substances from the sucked-in water vapor. Little surprise: thicker filters (30 mm) filter better than thinner ones (10 mm) that contain less activated carbon because the air dwells longer in thicker filters.

Good filters also regenerate well

Quality differences were also found to exist after regeneration of the filters by heating in the oven. With good filters, the degree of odor reduction decreased by only about 3 percent. With poorer filters, the cleaning power clearly decreased by 8 to 20 percent compared to the original cleaning power. In practice, these poor results mean that odors from cooking have to be discharged additionally through the window more often, with correspondingly higher heating costs.

Plasma filters without effect

The three plasma filters examined from two manufacturers disappointed. One device did not function at all; switching to a replacement device did not produce any improvement. With the other two plasma filters, the researchers could not determine any difference in terms of cleaning performance with and without an activated carbon filter or plasma filter. Thus, the cleaning effect was solely due to the activated carbon filter.

Do not lead water vapor into the kitchen cabinet

Together with still other results of the study, including on detection rates of range hoods, sensor-controlled power controls and the influence of different systems on the afterflow of air, an interesting picture emerges: when choosing an efficient range hood with a good cooking vapor detection rate that directs the air to the outside via aerodynamically optimal channels such as the innovative COMPAIR PRIME flow® and a wall penetration unit from Naber, no or only minimal restrictions in living comfort in a passive house are to be expected even in exhaust air mode. This also applies to smaller homes where the exhaust of the odor-, pollutant- and moisture-laden, warm room air has a greater impact on the energy balance. If automatic performance controls are used for the extractor hood, the influence decreases even more.

The study "Investigation of extractor hood systems in residential kitchens with regard to energetic, flow-technical and hygienic aspects" was commissioned by the German Federal Institute for Building, Urban and Space Research (BBSR) and subsidized by the German Federal Ministry of Public Works on the basis of funds from the "Future Building" innovation program. Involved were the Passive House Institute in Darmstadt, the ITG Institute for Technical Building Equipment and the Institute for Wood Technology, both in Dresden, as well as the company Naber from Nordhorn.