METHODS AND MEANS FOR ENERGY-EFFICIENT VENTILATION SYSTEMS FOR BUILDINGS

A ventilation system for a building (1)comprising a stairwell (2);a fire cell (3) separated from said stairwell (2) by a wall (4). Said ventilation system comprises an fresh air intake (5); a stale air exhaust (6);a means for providing air flow (7) in the ventilation system;a heat exchanger (8) arranged to exchange thermal energy between fresh air coming in from the air intake and stale air going out to the exhaust;a ventilation duct (9) arranged for transferring stale air from the fire cell (3) to the stale air exhaust (6) via the heat exchanger (8);a ventilation duct (10) arranged for transferring fresh air from the fresh air intake (5) to the stairwell (2) via the heat exchanger (8);a fire proof air transfer unit (100) arranged as a conduit for transferring air between the stairwell (2) and the fire cell (3). Fire proof air transfer unit suitable for said ventilation system, and uses thereof.