Indoor household gas heaters can be broadly categorized in one of two ways: flued or non-flued, or vented and unvented.
Beginning in 1881, the burner's flame was used to heat a structure made of asbestos, a design patented by Alice H.Parker, a England engineer.
Modern gas heaters have been further developed to include units that utilize radiant heat technology, rather than the principles of the Bunsen burner.
The flue, if properly installed with the correct overall height, size, and orientation should extract all of the heater emissions.
Home gas heating controls cycle using a mechanical or electronic thermostat.