Smoke is removed from a building interior by a system in which a controller is activated upon a signal from any of one or more smoke detectors connected thereto. A conduit, with an air-receiving end located in the building and an air-exhaust end located outside the building, has an associated air mover arranged to exhaust air from the building through the conduit. A first and second valve in the conduit are normally closed, preventing air flow. On a smoke detection signal from the controller, the first valve and second valve open, the air mover actuates and air/smoke is withdrawn from the building until a “reset” signal is received. On reset, the air mover shuts down and the first and second valves close. The air-receiving end is preferably directly connected through a forced-air HVAC system of the building to avail use of its ducts and air movers.