When you are having problems lighting a fire in your fireplace, it may be caused by a pressure issue in your home that is affecting the chimney draft. You may not realize this because you cannot see it, but the air in your home moves constantly. Typically, air attempts to flow out of the upper parts of your house, and more air flows into the lower parts of your house to make up for the air that left. If physics is not your strongest area, it can help to think of your home as a system to understand the reasons for airflow. Ace Chimney Sweeps would like to tell you about some of the pressure issues that can affect the airflow in your home to help you understand how it affects your chimney draft.

The Stack Effect

Stack Effect Air Pressure - Elkton MD - Ace Chimey Sweeps

You have probably heard your entire life that hot air rises, and this is true. The stack effect is when hot air rises into the upper areas of your house and is trapped because you have weatherized your home to be airtight. This can make it difficult for air to exit and for the make-up air to enter your house. According to the Chimney Safety Institute of America (CSIA), that trapped air creates pressure so that it can force its way out of your home through recessed light fixtures and window frames. Many times, the stack effect will cause outdoor air to enter your home through the chimney, which can bring in smoke and unpleasant odors from the flue when it enters.


If you are having problems with getting a fire started in your fireplace, you could be having backdrafting caused by the wind affecting the pressure in your home. When wind hits your house, it causes high pressure on the side where it hits (the windward side) and low pressure on the opposite side (the leeward side) of your home. To increase your chimney draft, you can open windows on the windward side, but if you open windows on the windward side, you can depressurize your home, which increases the likelihood of having a backdraft. Backdrafting is when your chimney draft is reversed so that smoke enters your home instead of going out of the chimney.

Interior Mechanical Devices

Another cause of depressurization of your home has to do with mechanical devices like fans, clothes dryers, and central vacuums. These devices can remove large amounts of air from your house, and this creates negative pressure around your fireplace. Other mechanical systems can also depressurize your house, including a forced-air furnace, especially one with leaky ducts. Since your fireplace needs a large amount of air for combustion, Ace Chimney Sweeps can help you deal with the negative pressure being caused by these devices.

Dealing with pressure issues can improve the draft in your chimney. Contact us at Ace Chimney Sweeps if you are experiencing any of these issues so that we can help you adjust the pressure in your house.