accessing . . .

accessing . . .

Home Care Library

Fireplace (gas)

The Home Wizard app calculates your ideal home care program to avoid problems with your Fireplace (gas), but sometimes trouble can still occur. Here are answers to questions about fireplace (gas) soot buildup.


Mr Wizard - I was taken by your answer to Cheryl, Oct 08, about her poofing sound and incomplete combustion. I have a NG fireplace that worked fine Oct-Dec except the poofing sound. A week or so ago, I started it up and filled the room with a smell the set off the smoke detector. I realized the logs and flue were fairly covered with soot and thought maybe the chimney needs cleaning. We bought the house in Aug and were told the chimney was clean. Also the weather has turned very cold and it seems to be rushing down the flue into the house. Related? Thank you for your advice.


Dear Nick:

Probably not what you had hoped to hear, but I would suggest that you not operate your gas fireplace until you can have a trained service person inspect it. You mentioned a number of things happening that are of concern.

Regarding the incident a week ago, I assume that you have a natural-vent gas fireplace, right? And I assume when you started it up, it was very cold outside? If your chimney is very tall and it's a very cold day, and if you don't open a window or outside door near where your fireplace is located, then your fireplace can have trouble creating a draft, which could be why you had the flue gas backing up into your room. This is especially true of houses with very tight construction. By opening the window or exterior door, it allows air to come into the house as the warm air is trying to rise up the cold chimney. Hot air rises, but if the chimney is long and cold, then it quickly cools the flue gas and makes the flue gas harder to rise. As more exhaust gas comes in, it gets backed up, and can therefore come back into the room.

This could be what happened with your incident a week ago, but it could be other combustion or flue problems. Especially since you mentioned that you are also getting a "poofing sound" and a significant amount of sooting, despite that you are burning clean natural gas. Plus, since it's a new house, you can't be sure of the service history on the unit. Gas fireplaces are great, but they can be dangerous if not adjusted and operated properly.

Regarding the cold air coming down the flue when the unit is turned off, does your unit have a lever for closing the damper in flue when the fireplace is not in use?

Hope this is helpful.


Mr Wizard - Thank you for your quick reply.

Yes, I do have a natural vent, it was very cold, and the chimney is tall. Will try opening the door, however, I'm not sure how "tight" our house is. Will have the poofing checked especially as I now realized how much soot was building up. I've had less burning firewood in previous homes. Thanks again.

This is a great resource.



Glad we could be of assistance. And glad to hear that you've decided to have your gas fireplace inspected by a service technician. Hopefully it will just need some adjustment and/or cleaning.



why does excessive carbon build up on the elements of a gas fireplace? There are 6 elements but only 3 & 5 get build up.


Dear Barry:

Is your gas fireplace fueled by propane or by natural gas? And is it a gas log model, or is it direct vent model?

When it comes to gas fireplaces, if you are having problems, I recommend that you involve a trained professional who can physically see and inspect your particular gas fireplace. Gas fireplaces are wonderful, but they can also be dangerous.

But with this said, in general, uneven carbon build-up on the elements of a gas fireplace indicate uneven flow of gas. This could be from how the logs are placed by the burner, or it could be due to irregularities in the burner itself.

Are you also seeing "delayed ignition" when you start the fireplace? That is, do you get a "poof" when it starts?

But again, it will help to know whether you are using propane or natural gas, and what style gas fireplace that you have.

Hope this is helpful.


This is a natural gas fireplace.



I am surprised that you are getting significant carbon build-up with a natural gas burning fireplace. Natural gas burns much cleaning than propane, where you can tend to see more carbon sooting.

Is it a direct vent or non-vented type model? In other words, does it have a tight-fitting glass cover in the front that keeps all of the products of combustion from coming into the room? Or is a model that is designed to allow combustion products to come into the room? If you are seeing evidence of uneven or incomplete combustion in a model that allows flue gas to enter the room, then I would recommend that you not use the unit until it can be inspected by a professional.

And lastly, when was the last time that you had a professionally trained service person clean, inspect and adjust your gas fireplace? To be safe, we recommend this be done once a year.


Open fronted 6 bar and inspected 3 months ago.



I would definitely recommend having it inspected by a professional service technician.

Soot build-up happening that fast from a natural gas burning fireplace is not normal, and is an indication of likely incomplete combustion, which produces deadly carbon monoxide gas. And since this is an open front model, this can be entering into your living spaces.

I would suggest not using it until your fireplace has been cleaned, inspected and adjusted by a trained service technician.


I have a peterson real-fyre gas log set (vented) that has been in place for about three years. It recently started creating a lot of soot in the room. I was wondering what might cause this and what can be done to remedy this.



Dear Ken:

First, if you are seeing soot coming into the room from your gas log fireplace, you should stop using it until you have your chimney checked.

Here is a webpage from that discusses gas log sooting problems:

As you will read in this webpage, the causes of gas log sooting can be: 1) that your chimney needs cleaning; and/or 2) that your gas logs need to be serviced. Either if these can lead to serious safety problems.

Hope this is helpful.

Fireplace (gas)

Home Inspections, Asbestos Inspections, Mold Assessor, Naca, 203k HUD and Radon Inspections