- Burners, furnaces, boilers, and strokers (2)
- Boilers, low-pressure heating: steam or hot water (25)
- Furnaces, domestic steam or hot water (7)
- Gas burners, industrial (10)
- Gas-oil burners, combination (4)
- Oil burners, domestic or industrial (7)
- Stokers, mechanical: domestic or industrial (2)
- Logs, gas fireplace (5)
- Radiators, except electric (18)
- Room heaters, except electric (10)
- Space heaters, except electric (1)
- Unit heaters, domestic (7)
- Wall heaters, except electric (1)
- Gas infrared heating units (7)
- Heaters, swimming pool: oil or gas (2)
- Solar heaters and collectors (19)
- Steam heating apparatus (5)
- Stoves, wood and coal burning (20)
