When a system like a furnace works almost around the clock, you can expect to encounter several problems due to which you might hear different odd sounds.
Noises like clanking, banging, screeching, whooshing, etc., indicate the furnace may have problems with the blower belt or bearings, screws, and bolts, fan motor. Some of these problems happen due to regular and tear. However, the moment you face this problem, call for support.