Also see if it happen when the heater fan is on.
Draft from direct vent gas fireplace.
A direct vent gas insert will stop those pesky drafts because the insert fits snugly inside the fireplace opening and the insert itself is a sealed firebox.
The direct vent fireplaces are sealed as far as the firebox goes so there should not be any drafts created by the flue.
Our magnetic fireplace vent covers stop drafts from vents circulating cold air.
There is an icy cold draft coming from the face of the unit mainly at the bottom where the controls are but the draft can be felt all around.
Use our magnetic fireplace vent covers to stop the draft instantly.
Easily removed and stored when you want to burn the fireplace.
We have a new direct vent gas fireplace installed flush to the wall in a new home.
Another great solution for preventing these drafts is to install a direct vent gas insert.
This insulated magnetic cover will stop all of the drafts that are coming in from the outside.
If so the area in and around the fireplace may be the source of make up air that the rest of your house needs for mechnical devices like fans hvac etc.
If you feel a draft try opening a window else where in the house to see in that reduces the air coming in.
Our flue zee flue covers and our termination cap covers deal with the draft of outside air coming in through your flue.
I suggest finding a plumbing company that specializes in gas fireplaces and a local contractor if this is not something you feel comfortable doing.
Draft decor products compliment each other and are versatile too.