Don’t Forget the Fireplace When Winterizing Your Home


Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation

One home feature that is popular because of its charm is the fireplace.  While many homeowners like to have one to provide a cozy room on cold, damp winter days you also have to remember that a fireplace represents a big hole leading up to the sky in your building envelope. If the chimney is not properly sealed when you are winterizing your home your indoor heat will simply go straight up the chimney.

In many homes, the chimney actually accounts for more air leakage than windows and doors.

Many homeowners, like me, don’t use their fireplace during the heating season because it is easy to create a back draft from the fireplace in an air tight home.  If I am using my fireplace and my furnace kicks on it will cause the smoke to back up into the house unless a window in the room is kept open a crack.

When you are not using your fireplace you should make sure that you have a system in place to seal the chimney and make it air tight.  Standard chimney dampers are simply not air-tight enough. There are two methods that could help tighten your chimney:

  • Install a chimney cap that will snug down on the top of the chimney that can be closed and opened by reaching into the chimney and pulling the chain to secure the cap – or release the cap – on the top of the chimney.
  • Install a bladder-like devise that – using the reverse air feature on your shop vacuum – will fill the bladder and create an air barrier.

There are dozens of common sense ways to deal with air leakage from your fireplace.

However, if you do choose an air tightening devise remember to remove it before you use your fireplace or you will have a major smoke event in your home!

Remember, you don’t have to sacrifice charm or aesthetics when working toward high efficiency in the home but you do need to minimize air loss everywhere you can.


  1. I have an insert in a stone fireplace and need insulation to surround the open space. I need to know if your company has a product that can be used in this situation.
    Please respond ASAP……’s getting cold!

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