Question: I have a gas fireplace that was installed by my builder. I have a brick chimney that would be fully functional should I chose to burn wood. How can I tell if the gas fireplace is supposed to be vented or non-vented? In addition, I have been told that I should only use logs appropriate to the brand of gas fireplace that was installed or I may run into the problem of excess carbon monoxide. . . The gas jet stick (I don't know what they are called) has the name Hearth Master on it. Have you ever heard of this brand? I was also told that logs are not sold without the entire unit. How is it, then that I have no logs, but seem to have the jets and a log holder? I am so confused. Answer: I have not heard of Hearth Master, but here's the scoop. If your gas fireplace was a factory built gas prefab unit (for gas only), then it must use the specific log set that came with it. Someone must have taken the logs if they are not there. If the gas fireplace has a vent to the outside, then it is vented. It might also have a vent outside that does not go up past the roof line - this is a "direct vent" fireplace. Maybe it's even a wood fireplace that had a gas log..or a gas starter installed in it. One other way to tell - most gas fireplaces have sealed doors that do not open. Best bet is to have a chimney sweep or other expert look at it to determine the proper use.