Why Is Cold Drafty Air Coming in My Chimney?

Fluesbrothers Chimney & Fireplace provides the greater Kansas City area, Shawnee KS, Shawnee Mission KS, Overland Park KS, Merriam KS, Gardner KS, Edgerton KS, De Soto KS and surrounding towns with top quality chimney services including solutions for cold air drafts coming from the chimney.

cold and drafty air coming out of fireplaceDuring this time of year, our crew gets many calls regarding cold air coming into homes from the fireplace or stove. The causes of this problem and the best solutions reveal some of the basic physics of chimneys. A chimney is a vertical shaft that conducts air and/or flue gases to the outdoors. When a fire is being burned in a fireplace or heating stove, the air or gas in the chimney flue is warmer than the outdoor air. Because of its buoyancy, the warm air or gas rises, creating the desired upward flow, ensuring the draft is properly venting the combustion byproducts out of the home.

However, there are occasions when the natural air pressure in your home pulls cold air from outside through the chimney, adding a chill to the room you are trying to keep warm and cozy. A home has a way of stabilizing air pressure, where hot air rises and cold air comes in by the way of least resistance or by natural pressure. The hot air that rises creates higher pressure at the top of your home and lower pressure area at the bottom of your home. In these low-pressure rooms towards the bottom half of your home, air will try find a way in. Fireplaces & heating stoves are a common source of least resistance, which is why you may be feeling cool air drafting in from the opening of your hearth.

Whether you feel a constant cold draft when a fire is not going or you feel gusts of cold air when it’s particularly windy outside, our certified chimney technicians in the Kansas City region can provide a solution to these cold drafty home invaders.

Top Sealing Dampers

When your fireplace is in use and you have a roaring fire burning in your hearth, your chimney serves as a necessary escape for smoke & gases. When the fireplace is not in use, your chimney acts like an open window or door. It sucks the warm, ambient air in your home out of the chimney and allows cool air to pour in. A top sealing chimney damper can solve this cold draft problem. Unlike traditional throat dampers, which feature a metal-on-metal closure, top sealing dampers feature a gasket closure that fully seal off the chimney opening when the fireplace isn’t in operation.

cold air coming in fireplace chimney repairInsulation

Improper insulation around a zero-clearance fireplace or insert may also provide a path for cold air to come into the home. If the fireplace unit is place on a wall whose back half faces the outside, proper insulation is critical. If insulation has dropped over time or was simply put in incorrectly, the gap between the wall and the fireplace will become a gathering place for cold air. Checking the status of insulation is not easy and may require pulling off siding or making a small hole so the insulated area can be seen. Our fully certified chimney sweeps may also utilize special chimney cameras for this task to reduce the amount of structural intrusion.

Avoid Creating a House Vacuum

Modern homes are usually designed to be airtight which can cause a problem when you use another appliance that requires air at the same time as your fireplace. When a kitchen vent, bathroom vent, furnace, or gas clothes drier utilizes the air within the home, new air cannot be drawn in through gaps in windows or doors due to airtight seals. As an alternative, cold air is drawn down the chimney to replace lost air in the home. A good way to lessen a chilly chimney draft is by aiming to use ventilation fans less frequently or cracking a window ever so slightly near the appliance that’s being operated so new air can freely come in and re-stabilize the air pressure in the home.

If you are suffering from the “cold hearth syndrome,” please contact our chimney & fireplace professionals today. A thorough chimney inspection will let you know if there are additional issues that need attention and our crew will be able to ensure you can enjoy your fireplace or heating stove while also avoiding cold air drafts from your chimney. Call Fluesbrothers at (913) 236-7141.