Every summer when the weather gets hot and humid, Mr. Smokestack Chimney Service gets calls from our customers asking us why stinky smells are invading their homes from their chimneys. Several different things could be causing these unpleasant odors, including creosote, soot, water, leaves, or a trapped or dead bird or animal, but there is a reason why these bad smells are coming into your home through the chimney. According to the Chimney Safety Institute of America (CSIA), negative air 
pressure affects your chimney by changing the direction of the chimney draft. Instead of smoke and unpleasant odors exiting out of your home through the chimney, negative air pressure forces the draft back into your home. No matter what the odor source is, negative air pressure is why those stinky smells are getting into your home. We would like to tell you more about what causes negative air pressure and how to can correct this problem.
Why do I have negative air pressure in my home?
Many homeowners weatherize their homes by sealing off any air cracks in their doors and windows, and although weatherization can save you money on your utility bills, it also creates negative air pressure because you have no way of getting outside air into your home, except through the fireplace and chimney. Other things besides weatherization can cause negative air pressure, including new furnace installation, new roofing, and new bathroom or kitchen exhaust fans.
How can I correct negative air pressure?
There are several ways to combat negative air pressure, but the trick is finding the right balance of a combination of these ways. Mr. Smokestack Chimney Service recommends trying the following steps to correct air pressure:
- Close the fireplace damper when the fireplace is not in use.
- Install glass fireplace doors to keep warm air from escaping when a fire is burning.
- Update your chimney cap and damper by having a top-sealing damper installed. This type of damper has an airtight seal that does a great job of monitoring airflow.
- Provide combustion air to your combustion appliances by opening a window in the same room as the appliance to balance the air pressure.
If you are noticing unpleasant odors coming from your chimney, contact us at Mr. Smokestack Chimney Service. We can take care of the source of the odor and help you correct any negative air pressure problems.
