Rangehoods
Rangehoods are best employed in a passive house or low energy build with their own internal filtering (via air filter) for energy efficiency.
Rangehoods are those fast exhaust fans over your cooktop. Hard at work while you cook, removing smoke, steam and odours — but they can be a real problem for a passive house or low energy build. Known sometimes as a cooker hood traditional exhaust fans take smoke and exhaust from the cooktop and send it outside. The problem is that along with that overcooked sausage smoke, heat energy also goes, at a rate comparable to opening a window. A rangehood sucking heat energy out of your kitchen can defeat the purpose of a heat recovery ventilation system in a passive house or low energy build.
The solution might be a recirculating rangehood, which recirculates filtered air back into the kitchen, these can be equipped with various air filters, including active carbon air filters to remove that smoking sausage odour. This solution is easier on the ventilation system overall, but in a kitchen that gets an intensive, high filter use, this may not be the best option. Another solution is to use the rangehood traditionally but supply the same amount of air back into the home. Recirculation systems generally operate at 300 to 500 m³ per hour, however a rangehood running to contain fumes from cooking gets up to 1000 to 3000 m³ per hour — this imbalance can create a vacuum unless we install a release valve for when the rangehood is in operation. This intake is where we encounter heat loss as well as possible condensation points forming in the system. A relatively new third solution of plasma air filters is now available which does the same intensive filtering but does away with the need for filter cartridges.