The system works by removing air from wet rooms e.g. bathrooms and kitchens and exchanging the heat with incoming fresh air which is then supplied to general living areas.
In a modern reasonable airtight and adequately insulated house it is estimated that 30% of the heat loss is through standard ventilation. Heat Recovery units can recycle over 90% of this heat which is otherwise completely wasted. The result is considerable energy savings as well as a filtered air supply providing a fresher, healthier indoor atmosphere. These systems can be applied to a single room or whole house. The systems can be retro fitted to an existing property and very often with minimal disruption. The main unit will usually go in the loft, and the system can be individually designed to be discreet.
One unit discretely situated in a loft or cupboard will more than adequately ventilate most properties. The units use minimal power and are extremely quiet. In most situations using them saves considerably more energy than they use, knows as "Net Energy Gain".