Anatomy of Your Chimney

How your chimney works?

Your chimney is a living, breathing structure within your home that can be extremely functional.  Many people think of their fireplace as a community-gathering place on cold winter evenings.  Others use their fireplace as another heating source.  Fireplaces also provide great aesthetic value but despite all the positives that come with your glowing fire, there is still a dangerous element that comes with operating a home fireplace. 

One of the first things that a homeowner needs to know is what type of fireplace is in your home?   Home fireplaces generally come in two different types, masonry fireplaces and factory built fireplaces.  Your typical masonry fireplace is built entirely of brick and mortar and depending on the size of your home can be anywhere from four to seven tons in weight.  A factory or pre-built fireplace is an all-in-one structure from the ground up, meaning that the metal firebox also has a pre-built chimney attached to it, along with some other features that are model specific.

So, how does your chimney work?  First off your chimney is designed to provide an exit path for the combustibles that you burn inside your fireplace.  The smoke and gasses rise up the chimney through a process known as draft and flow.  When you have a roaring fire going in your home the warmer gasses in the flue rise, while the cooler fresh air from the outside has more pressure and draws the air back down into the chimney creating combustion and the draft and flow effect.

Chimney pressure inside your house is affected by a few key factors and if not monitored or addressed can cause the draft and flow system to not work properly.  The three main factors that affect the pressure system process are the amount of adequate air within the house, the air movement in the house and finally the competition for this available air that exists in the house.   Open windows, a poorly insulated or drafty home, a tall stairwell or anything else that allows hot air to exit the house, can overcome the draft and flow system and allow smoke to enter the house rather than exit through your chimney.