Why Is There Water On The Inside Glass Of My Gas Fireplace?

You click the remote on and by the time you nestle into your favorite chair, you notice small water droplets forming on the inside of the fireplace.  Is this dangerous?  Will it cause any damage to the gas fireplace?  Can it be prevented?  If this has ever happened to you or if you have ever asked yourself these questions, you will want to read this article.


Temperature difference is the main reason that moisture forms on the inside of the glass on your gas fireplace, free-standing gas stove or fireplace insert.  If one would measure the inside temperature of the firebox and the room temperature when the fireplace is off, you would see that the temperature is similar.  But turn the fireplace on and the temperature in the firebox changes very quickly.

The heat from the gas flames warms the air inside the fireplace.  And, warmer air has more moisture than cooler air.  As discussed in other articles, one of the by-products of combustion is water vapor.  As the water vapor in the warming air comes in contact with the cooler glass surface, condensation forms on the inside of the glass.  As the inside of the fireplace gets hotter and the steel, refractory and logs in the fireplace begin the heat up, the condensation will begin to evaporate and the glass will clear itself.

You will likely notice the gas flames looking a bit too blue upon initial start-up.  This is especially true with natural gas.  LP gas to a lesser extent.  As the flames begin to yellow-up, normally after 5 minutes or so, the condensation on the glass has already begun to clear itself.


Condensation on the inside of glass is actually quite common and really nothing to be too concerned about.  It can be a bit irritating, but nothing on the fireplace will be damaged.  Condensation forming on the inside of the glass at start-up is not unusual and is no cause for alarm.


If a white, foggy film develops on the inside of the glass, this is a different story.  By-products from the combustion process, including Sulphur, can accumulate with the condensation on the glass.  If left unchecked, this can build-up and form a white, acidic film.  This needs to be removed.  To take the glass off your gas appliance, refer to your owner’s manual.  The latching or sealing mechanism will vary from model to model and from one manufacturer to another.  If you need help removing and cleaning the glass, just call your WE LOVE FIRE expert for assistance.


Over time and if the condensation is heavy, you may begin to notice water marked streaks on the inside of the glass.  These water lines as well as the white hazy film can be cleaned quite easily.  A gas appliance cleaning product is what you will need.  Usually around $10.00/bottle, this cleaner is a thick, creamy, paste-like polish designed to clean the glass on your fireplace, stove or insert.  And, your WE LOVE FIRE dealer has a supply on the counter.  It’s easy to use, just follow the directions on the bottle.

If your glass has any black soot deposits building up on the inside, this normally indicates an issue with the amount of combustion air that’s mixing with the gas.  This will require a technical adjustment that should be made by a qualified service technician.  This soot can be easily cleaned with the same gas appliance cleaning polish.

Below is a list of fireplace and grill stores that service Virginia (VA)

Manassas, VA

Winston's Chimney Service
11301 Industrial Road
Manassas, VA 20109

Winston's Chimney Service LogoVisit Store Page

Mechanicsville, VA

Hearth & Home Shoppe
8151 Mechanicsville Tpk
Mechanicsville, VA 23111

Hearth & Home Shoppe LogoVisit Store Page

Roanoke, VA

Dixie Building Products Inc.
3342 Melrose Ave NW
Roanoke, VA 24017

Warrenton, VA

Costello's Warrenton Fireplace & Hot Tub
251 West Lee Hwy
Warrenton, VA 20186

For more information, contact your local fireplace and grill store..

12 Responses

  1. Linda Luigs
    I understand the condensation on the glass, but what if the condensation is so thick that it drips water down the glass? It also take a while for it to clear up and have no condensation. We are also getting soot on the outside of the glass. Any help would be appreciated.
    • Dominique Page
      Hello Linda Thanks for your comment. I believe a service call is in order. Soot is not normal at all on a gas fireplace. There should not be any. Either the logs are out of place or the burner needs attention or the air adjustment needs to be tuned. Dominique
  2. beverly gardner
    i have a see through fireplace in my basement - this is a new construction. during the summer I noticed water running down the glass. they keep telling this is normal but it was running down the glass and that was not happening upstairs and others that I know never seen that. This fireplace also has a lighting system - after the summer the lights would not work and they came to fix them. i was told they had rust and he replaced the parts. This fireplace is not even 1 year old - I think the rust is from the condensation. What are your thoughts?
    • Dominique Page
      Hi Beverly Thanks for your message. Sorry you are having issues with your fireplace. I am guessing this is a gas fireplace? I certainly would encourage you to look at 'cause and effect'. Is the water dripping in when it rains? If yes, look at the venting termination outside. It might not be sealed properly. If the water is dripping and there has been no rain, where can it come from? Is there an air conditioning dripping water near the fireplace? Condensation comes from the temperature differences. Is it worst when very cold outside? Is it happening when snow is melting? Is there ice on the venting termination outside? All I can do is giving you hints to look at...A local should be able to help you find the source. Sorry I was not able to be of anymore help. Dominique
    • Helen
      Hi I have been having the same problems with a new gas fire, condensation runs down the glass, it’s collecting and stains the metal work inside, also white stains on the rear black mirror. I was wondering what make fire you have, mine is a Loft by Gazco it cost £2000 and it looks a mess. Also the battery corroded and the fire wouldn’t ignite. Engineer on his 3rd visit.
      • Dominique Page
        Hello Beverly Sorry you are having issues with your gas fire. I would suggest you call a gas fireplace tech to come and inspect your fire. We are in North America. So I cannot be of much help... Dominique
  3. Donna
    I have lived in my condo since 2009, today I noticed condensation on the inside of the front of the fireplace. Keep in mind, I HAVE NOT turned my fireplace on in over 10 years. What can this be? Also, smells a little damp when I get close to the fireplace. Thank you kindly! Donna
    • Dominique Page
      Hello Donna Thanks for reaching out. I don't know where you live, but if it has been very humid lately, there may be humidity trapped inside your fireplace. If you have not used it in 10 years, it might be a good idea to have it inspected. Ideally, to get rid of the humidity, turning on the fireplace for 15 minutes would do the trick...but, I highly recommend to have it inspected prior to turning it on. Dominique
  4. Reeves
    We're designing a bathroom which includes a double-sided gas fireplace with a tub (in-deck) about 12" parallel to the wall and centered under the fireplace. The fireplace window will be about 9" above the deck of the tub and slightly shorter (36") than the tub (60"). The fireplace has ceramic glass. Do we need to be concerned about the possibility of water occasionally being splashed on the hot ceramic glass? Are there any other design concerns that we should consider? Thanks!
    • Dominique Page
      Hello Reeves Thanks for your comment. Here's our thoughts on your project: Be sure and check with your fireplace dealer. Splashing cooler water on a hot surface could cause thermo-shocking of the glass and cause it to break. Ceramic glass is quite expensive. Try to keep all water off the hot glass! All the best on your projet!
  5. Jason
    We have a new home in NC. Our gas fireplace continuously fogs up on the inside of the glass. We have barely used it, but it seems like it should not be getting moisture build up almost daily. Yes, we have had humid days. But shouldn’t it be insulated properly for prevent this.
    • Dominique Page
      Hello Jason Thanks for reaching out. The best way to find this fix is to get a technician to come in. We might have a Partner Store near you. If not, search for the local fireplace store.

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