Why does smoke come into the room after my fireplace has been
burning for awhile?
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Like a lot of questions, there are so many answers to this one that is
would take a small book to explain most of them. In fact, this has become
so prevalent that the Chimney Safety Institute of America has several
courses on this subject over multiple days of classes.
Today's energy prices for homes are on an upward curve, although the
winter of 2006-2007 is supposed to be a bit better priced than last year.
For years, builders and homeowners have been tightening the envelope
of the home to help cut down the energy bills. Basically, that means that if
you find a spot where air is leaking into the house, then you do something,
such as caulking or insulation to stop the air flow.
When you are burning a fireplace, unless you use an outside air feed,
your house air is being used to feed the fire. If you have opened your
glass doors, you then have a tremendous amount of house air going up
the chimney.
Other events in the house that can also contribute to the exodus of the
interior air are: running of a bathroom vent, clothes dryer, combustion
furnaces, and down draft kitchen stove vents really pull a lot of air out of
the house. If you have several of these conditions activated as well as the
fireplace burning, you can create what is called "negative pressure" in
the house.
The way I explain negative pressure in a very easy to understand way is:
take a deep breath and hold it for a second. Your lungs now represent the
air in your house. Let as much air as possible out of your lungs. This
represents the air exiting your house through various means. After all of
the air is out of your lungs, just take a pause. What do you want to do? (Or
should I say "What do you have to do?") You must breathe in or your body
will start to struggle to pull air in through any means possible, which
means either your nose or mouth.
Your house reacts in the same way. It wants to have equal pressure
inside and outside. The house will use the easiest way possible to bring in
more air. The fireplace now becomes a source of incoming airflow. It
doesn't matter if there is a fire burning that is producing smoke. The
airflow in the chimney will be reversed, along with the reversal of the
smoke.
All of a sudden, your nice cozy fire is filling the house with smoke.
This is a very common problem. But there can also be other reasons.
Some of these are: the dimensions of the firebox, the placement of the
damper, and the size of the flue, just to name a few.
Sometimes it takes a trained Certified Sweep to analyze the problem.
That is one of the values of Certification and continuing education
courses. That is also why these processes are part of the core beliefs of
Abbey Road Chimney Sweeps, Inc.
