The principle for a ventilation-heat recovery system with supply and extract air is simple. Harmful contaminants and moisture held in the interior air is removed via the extraction vents in the “dirty rooms”; kitchen, bath, toilets and utility rooms. Before leaving the house, the old air gives off its heat to the fresh incoming air in the heat-exchange unit.
With a balanced mechanical system, you control the amount of ventilation in the house. Not too much on windy and cold days and enough on humid and mild days. At the same time the incoming air is filtered from dust and pollen. The system allows you to determine where you want the fresh air to be introduced, in what quantities and at what temperature. The fresh new air is normally supplied through a vent in the ceiling in the “clean rooms” such as bedrooms and living rooms.