This means that you'll be able to search for NAICS codes directly (if that's your jam). We'll do the math; let's make better data on public procurement together.
Boilers, 15 pounds WSP and under (for boilers over 15 pounds WSP, see FSC 4410); Domestic Water Storage Tanks through 100 gallon capacity; Fireplace Heaters; Furnaces; Space Heaters; Heating Radiators; Immersion Heaters; Water Heaters, through 100 gallon recovery capacity (for heaters over 100 gallons recovery capacity, see FSC 4410).
Vehicle Heaters (FSC 2540); Aircraft Heaters (FSC 1660).
Possible NAICS Codes
333414 – Heating Equipment (except Warm Air Furnaces) Manufacturing
238220 – Plumbing, Heating, and Air-Conditioning Contractors
333415 – Air-Conditioning and Warm Air Heating Equipment and Commercial and Industrial Refrigeration Equipment Manufacturing
423720 – Plumbing and Heating Equipment and Supplies (Hydronics) Merchant Wholesalers
333318 – Other Commercial and Service Industry Machinery Manufacturing
444130 – Hardware Stores
423730 – Warm Air Heating and Air-Conditioning Equipment and Supplies Merchant Wholesalers
332410 – Power Boiler and Heat Exchanger Manufacturing
335210 – Small Electrical Appliance Manufacturing
332323 – Ornamental and Architectural Metal Work Manufacturing