Old homes can have many charming features – carved wood, old fixtures, fireplaces. But a beautiful old wood burning fireplace or stove can have a serious affect on your indoor air quality if it’s not kept clean and in good repair.
If your home was built before the 1950s, it likely has an old masonry fireplace and chimney. Though the coziness of having a crackling fire is tempting, wood smoke can release many harmful pollutants into your indoor air quality, especially if it is old or cracked, or if you’re burning improperly or burning bad materials.
Burning wood creates smoke that may contain compounds that affect your indoor air quality and health. In a well-functioning chimney, there should be minimal affect to your indoor air quality – smoke is drawn up the flue and vented outdoors. But there are a number of ways that your chimney may not be functioning properly and could be affecting your indoor air quality.
Burning creates gasses that can contain creosote, carbon monoxide, and other chemicals. Your chimney should be reducing their levels in your indoor air quality by safely venting them up the sealed flue tiles in your chimney. But over time, the mortar keeping your flue sealed can erode, leaving gaps between the tiles – instead of leaving your home, they are often drawn by air pressure back into your home where they affect your indoor air quality and can rapidly spread into many rooms. Cracks in the flue tiles themselves may have a similar affect on your indoor air quality. Tiles may crack due to chimney fires, seismic events, or even just the settling of you home.
Over the lifetime of your chimney, a small crack here or there shouldn’t cause too many indoor air quality problems. It’s when these cracks and creosote buildup that they can start having serious indoor air quality effects as well as more serious events, such as fires. Fires can start when things (such as birds nests, fallen bricks, or leaves) lodge in your chimney. While at first you may just notice more smoke in your indoor air quality, over time, the heat and gasses from a fire can ignite these objects and start a fire.
One of the biggest worries of an improperly maintained fireplace is carbon monoxide poisoning. Carbon monoxide is a colourless, odourless gas that can enter our indoor air quality when something – like wood burning in a fireplace – doesn’t get enough air to burn up completely. Slightly denser than air, carbon monoxide is deadly to humans and their pets; it’s often called ‘The Silent Killer’ because you may not even know that it is affecting your indoor air quality until it’s too late. Other chemicals that can be released into your indoor air quality by a fireplace are nitrogen oxides, sulphur dioxide, hydrocarbons, and formaldehyde. All are serious indoor air quality pollutants which can have a dangerous cumulative affect on your health.
Maintaining your chimney to prevent these indoor air quality problems or more serious events, like a fire, should be part of your spring or fall home maintenance ritual. Preserving the character of your home and the cozy crackle of wood can be safely enjoyed without any risks to your indoor air quality or health, and with professional help, can be easy to achieve.