Recirculation cooker hoods draw in cooking vapours, filtering the air through a charcoal filter and then re-circulating the cleaned air back into the kitchen, leaving it free from cooking odours. The carbon filtration process guarantees air purification and a pleasant cooking environment. This active carbon filter absorbs grease and moisture while cooking, preventing unpleasant odours in the kitchen. The non-toxic charcoal in the filter works under any temperature or humidity conditions. To keep your kitchen smelling fresh it is recommended that you replace the carbon filter every 3 to 4 months, depending on the cooker hood usage and type of cooking (fried, fatty food, steam etc.).