Gas furnace

A gas furnace comprising:

• a burner in which a mixture of air and fuel gas burns;
• a heat exchanger through which a combustion gas produced by the combustion of the mixture flows;
• a duct comprising a room air duct through which air coming from a room passes and a supply air duct through which air supplied to the room passes;
• a blower that induces a flow of the room air supplied as the supply air to the room through the heat exchanger;
• and
• a humidification and dehumidification device being installed on one side of the supply air duct for adjusting the amount of moisture contained in the supply air,
• wherein the humidification and dehumidification device comprises:
• a rotor with an adsorbent coated on the surface that rotates in a certain direction, the rotor comprising a first portion located inside the supply air duct and a second portion located outside the supply air duct;
• a casing that accommodates the second portion therein and has a first air-through hole and a second air-through hole formed therein, with a flow path of air passing through the second portion between the first and second air-through holes;
• a guiding member placed on one side of the rotor, the guiding member comprises a first partition wall separating the first and second portions and a third partition wall separating the second portion into at least two parts,
• wherein the first and second air-through holes correspond in position to the at least two parts separated by the third partition wall, and
• wherein there is no water supply installed on the humidification and dehumidification device.