This industry comprises establishments primarily engaged in manufacturing ventilating, heating, air-conditioning, and commercial and industrial refrigeration and freezer equipment.

Cross-References. Establishments primarily engaged in--

• 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 33241, Power Boiler and Heat Exchanger Manufacturing;
• Manufacturing industrial process furnaces and ovens--are c lassified 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.