Extraction cleaner with heat transfer

An extraction cleaner for cleaning a floor surface, comprising:

• a supply tank configured to store a supply of cleaning liquid;
• a liquid distribution system configured to apply the cleaning liquid to the floor surface;
• a liquid recovery system configured to recover applied liquid and dirt from the floor surface, the liquid recovery system comprising:
• a recovery tank configured to store recovered cleaning liquid and dirt;
• a suction nozzle in fluid communication with the recovery tank;
• and
• a motor generating working air flow;
• a motor-cooling air pathway providing cooling air to the motor and removing heated cooling air from the motor;
• and
• a duct system fluidly downstream of the motor and comprising:
• a heat transfer duct fluidly coupled to the motor-cooling air pathway and delivering heated motor cooling air from the motor to the supply tank to heat the cleaning liquid stored therein;
• and
• a drain outlet fluidly coupled to the heat transfer duct, wherein the drain outlet drains cleaning liquid that enters the heat transfer duct away from the motor.