On Oct 14, 8:58*pm, "cm" wrote:
We have a two sided fireplace in our house. The house is 18 years old and
the fireplace is original to the house. We purchased the house about a year
ago. We tried several times last winter to have a fire and most of the time
smoke backed up in the house. We have tried having a window partially/fully
open and warming the chimney prior to lighting the logs, with no luck.

I measured the chimney height tonight and it is taller than it needs to be.
I was told it needs to be 2' taller than the point where it is 10' away from
the roof. There is a large rooftop A/C unit 7' feet away from the chimney
that is 2' taller than the chimney. Should I raise the chimney above the A/C
unit? What else should I look for?

Thanks,

cm

Once I get fire started, I have glass doors to keep out smoke let
enough air in to support combustion.
My fireplace in family room was problem because when furnace came on
nearby it created negative pressure in room drawing smoke out of
fireplace. Part of solution was keeping doors open to room from other
parts of house. You would do well to sweep chimney yourself or have
it done, just to check out your system and make sure there is no
creosote build up.