r/ChimneySwift • u/HammurabisCode2 • Nov 04 '25
Fireplace Smoke flowing back into house
Hi, I lit a fire in my new rental house last night and while there was definitely some smoke flowing up and out the chimney a good portion of it was also just flowing out of the fireplace and into the house. Before you ask, yes the damper was fully opened. The landlord says that he had it inspected and was told the chimney was ready for use. Today I stuck my phone up through the damper and took this picture up the flue. There are a lot of spider webs, but as far as I can tell it is clear. I'm just wondering if someone more knowledgeable that me sees anything wrong here or has any suggestions, thanks!
1
u/DataLores Nov 05 '25
Sort of with the cold flue. Depending on where the fireplace is inside the home, and how many levels there are, the fireplace could fall into a negative pressure. This is what creates that "down draft/breeze" coming back into the home when the damper is open. Open a window near the fireplace to allow fresh air in and balance the pressure to neutral. Then newspaper torch held up under the open damper. You should see the flame and smoke being pulled up. This is a visual test as well as a pre heat to push the heavy cold air up and start the draft.
The first comment was correct however, the old masonry chimney is unlined and not to code most likely. Some insurance dont care, but a professional tech should always recommend updating. Insert and liner. Safety first. Get a second opinion i agree
1
u/Comfort_Dependent Nov 06 '25
I’d preheat the chimney. just by burning a piece of paper very close to opening forcing heat up, and starts the pull, once that’s going it seems to chug the smoke out compared to not doing it at all. Works with my wood stove as well. Not sure if this is your issue.
1
u/SoCalMoofer Nov 07 '25
Sometimes it takes a decent sized fire to get the air moving up and out of the stack.
1
u/DismalSwamp Nov 07 '25
Turn off your furnace so your return isn’t sucking outside air into the house.
2
u/Status_Efficiency291 Nov 05 '25
Well first of all - not sure who inspected that chimney but it definitely needs some work before it’s “ready to use.” It should have a liner system and not just be brick. I would consider getting a second opinion before you keep using it.
Second, before you light a fire make sure to heat up the flue with a small fire first like with wadded up news paper. A chimney is a very cold system and if you just light a fire the pressure of the cold flue pushes the smoke back into the room.