A furnace burning smell that smells like rubber is a sign something needs attention. In older furnaces with belt-driven blowers, a slipping or worn belt can give off that odour. In newer furnaces, it can come from damaged wire coating or something caught in the blower. Either way, it isn't a smell to wait out: turn the furnace off and have a technician check it. Purcell Heating & Air in Calgary explains what causes a rubber smell and how a licensed technician finds and fixes the problem.