Fireplace as required heat source

[Tom Rees]

What are the requirements for a gas fireplace to fill the requirement that every habitable space (IRC 303.8 Required heating) have a heat source. This comes up often that an addition such as a family room is put on the house and they didn't extend the heat ducts to this room but did install a gas fireplace in the addition. I think I remember that the fireplace had to have a thermostat but I am not sure. Thank you.

[Jerry Peck - Codeman]

While the code does not clearly state that a 'heater' without a thermostat is not permitted to be counted as 'the' required heat source, the wording of the code clearly indicates that is the intent:

(bold and underlining are mine)
- R303.10 Required heating.
- - Where the winter design temperature in Table R301.2(1) is below 60°F (16°C), every dwelling unit shall be provided with heating facilities capable of maintaining a room temperature of not less than 68°F (20°C) at a point 3 feet (914 mm) above the floor and 2 feet (610 mm) from exterior walls in habitable rooms at the design temperature. The installation of one or more portable space heaters shall not be used to achieve compliance with this section.

"capable of maintaining"

How else can that be done without the use of a thermostat?

I suppose someone could try to claim that if a fireplace produces enough heat to provide the required heat for the coldest day/night to be experienced, one could stretch that to mean 'turn the heat ALL THE WAY UP' and roast when it gets too hot ... just so it will be hot enough to meet the coldest cold?

Not in my book, but people will stretch things to be cheap.

If there is no thermostat, then the gas fireplace doesn't count. And, just because there is a thermostat for the gas fireplace does not mean it counts either as it may not have a high enough Btu/hr rating to heat the area.

While we have a central heating system, we also have a gas fireplace in the great room (living room/family room with 14 foot peak at the ceiling), with a remote, and there is a thermostat in the remote - but even on high setting, the gas fireplace does not produce heat to get warm beyond about 4 feet into the room from the fireplace. We only use the fireplace for sitting in front of it for the effect of sitting in front of a fire - it is not needed for heating ability.