Is a separate air supply also needed for an extractor hood that vents outside?

Yes, in many cases it is. An extractor hood that vents air outside temporarily draws a lot of air out of the home while cooking. The Fresh-r Compac cannot replace that extra extraction, because the Compac keeps its supply and extract air in balance.

A window trickle vent or a dedicated facade vent in or near the kitchen gives the extractor hood enough replacement air. This allows the hood to better capture cooking fumes, moisture and — when cooking on gas — any combustion gases. Without sufficient supply air, the extractor hood can perform less well, and cooking fumes or moisture can linger in the home for longer.