The Rumford Store
Gas Logs

Dampers and Doors

Do I have to remove or block open the damper on my fireplace and install doors if I install a gas log set?

The simple answer is "maybe". But does it make sense? "No".

Fireplace experts generally recommend removing the damper because the customer will forget to open the damper and gas logs emit lots of carbon monoxide becasue they burn rich to mimic the look of a yellow wood fire flame.

But leving the damper open all the time wastes a lot of heat up the chimney.

So how about fireplace doors? They are expensive and we alreay know that they don't block much air see The Skinny on Fireplace Doors.

There are also electonic dampers like the Eco Damper. They work in conjunction with chimney-top fans and electronic gas log ingnisition systems. You click the remote which turns on the fan which opens the damper which closes a switch to ignight the gas logs. Now you're talking real money. The electronic dampers leak about 15% when closed and the complicated systems are useless if the electricity goes off.

So what do the codes say?

The International Residencial Code (IRC) is silent on the issue except for a note in an apendix on inspections that requires the damper to be open ...

    IRC Apendix 9 Inspections
    (7) Gas Log Sets and Gas Fireplaces
    a. For gas logs installed in wood burning
    fireplaces equipped with a damper, verify that the fireplace damper is in a fixed open position.
The California Energy Code requires tight-fitting fireplaces dampers but in an appaarent contradiction requires that the dampers for fireplaces fitted with gas logs the "shall be blocked open if required by the CMC or the manufacturer's installation instructions."

Here is what Rasmussen Iron Works, the manufacturer of our Rumford gs logs, says ...

    Practically speaking, the damper can be closed when the unit is not burning, so that heat may be kept inside the room. The same is true of glass doors (open when burning, closed when off). However, many jurisdictions have determined that people cannot be trusted to open the damper before using their gas log set (sarcasm), so the damper must be either removed or permanently blocked open. In such cases, glass doors provide you the ability to keep the heat inside the room when not burning your gas log set.
A lot of confustion and contradictory advice.

Here is what we recommend: Since the concern is that you will forget to open the dmaper when you light the gas logs, install a good carbon monoxide detector. CO detectors work well and are widely available for about $100. Chances are you won't have to comply with any of the codes which seem to be selectively enforced but, if you do, all codes allow for "alternative methods and materials" to comply with the intent of the code.

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