In order to function properly, every fireplace needs a source of oxygen. Oxygen is a vital component of combustion, which the process that results in fire, and the fire will draw oxygen from the most readily available sources to continue burning. Many fireplaces take oxygen directly from inside the home. This causes a wide range of problems, but fortunately, they can be solved by installing an outdoor air kit to funnel in outside air for combustion.
The most common traditional fireplaces rely on the correct flow of air, also known as the draft, to function properly. Hot air from the fire rises through the chimney, making room for fresh oxygenated air to enter the fire. This flow of air into the fire and up through chimney is necessary to keep the dangerous gases produced by the fire from filling the house. Fireplaces commonly draw new air into the fire from the house, which can cause several problems.
First, the air being pulled from the house must be replaced somehow in order for the fire to continue burning. In older homes, this generally happens by outside air entering the home through tiny openings around windows and doors. However, newer homes are built more and more airtight to increase energy efficiency, which makes replacing the air taken by the fireplace much more difficult.
When air is taken from the home and cannot be replaced, the draft can actually reverse directions. The pressure in the house can reach such a low point that the fire begins drawing air to burn through the chimney and expelling the smoke and other gases right into the home. Not only does this fill the home with irritating, smelly smoke, but it can also cause problems like carbon monoxide poisoning. A quick way to test if this pressure change is to blame for the back draft is to open a window. If the smoke stops filling the house, there was too little oxygen and pressure inside the house.
Whether you have to open a window or the house is drafty enough to replace the indoor air through cracks, the air coming into the house is still cold outdoor air. When burning a fire, you probably do not expect to make your house colder, but this is likely the case. To prevent this from happening, an outdoor air kit can be installed by a chimney specialist. These kits are designed to funnel outdoor air directly into the fire, which avoids using the inside air to fuel the fire. In turn, this prevents back draft resulting from lowered pressure, keeps air quality higher by not burning indoor oxygen, and does not waste furnace-heated air on fueling the fire.
If you suspect an issue with your fireplace burning too much indoor air, contact a chimney expert to discuss installing an outdoor air kit. In the area of D.C., get in touch with Winston’s Chimney Service to speak with a professional.