This industry comprises establishments primarily engaged in manufacturing ventilating, heating, air-conditioning, and commercial and industrial refrigeration and freezer equipment. Manufacturing household-type fans (except attic), portable electric space heaters, humidifiers, dehumidifiers, and air purification equipment--are classified in Industry 33521, Small Electrical Appliance Manufacturing; Manufacturing household-type appliances, such as cooking stoves, ranges, refrigerators, and freezers--are classified in Industry 33522, Major Appliance Manufacturing; Manufacturing commercial-type cooking equipment--are classified in Industry 33329, Other Industrial Machinery Manufacturing; Manufacturing industrial, power, and marine boilers--are classified in Industry 332410, Power Boiler and Heat Exchanger Manufacturing; Manufacturing industrial process furnaces and ovens--are classified in Industry 33399, All Other General Purpose Machinery Manufacturing; and Manufacturing motor vehicle air-conditioning systems and compressors--are classified in Industry 33639, Other Motor Vehicle Parts Manufacturing.