Saving energy at home: Chimney flue maintenance

If you have a fireplace, you know the feeling of walking by one when not in use and shivering from the cold.

My sister’s house was built in 1910, the same year as my house was built. The people who built her house gave her a fireplace. I suspect the people who built mine installed a wooden stove in the living room that was removed long ago.

On a recent visit to her house, I noticed a breeze. She said she had no idea if the flue was open or not, even though she has never used her fireplace over the years.

I showed her Avista’s website that talks about fireplaces at Tom Lienhard, Avista’s chief efficiency engineer, offers some expert advice for making your home more energy efficient.

He said that when you have an open flue in your chimney, the warm air escapes through the chimney and the cold air from outside is forced into your home. For this reason, you should use your wood-burning fireplace sparingly (with the flue open, of course).

At my sister’s house, we suspected her flue was open. Her fireplace has a natural gas insert that was there when she moved in years ago. I don’t think she’s ever used it and she thinks if she ever wanted to, she would have a professional come in and change out the insert.

She had a professional chimney sweep come by many years ago, but since then, she hasn’t thought about her fireplace very much. We took a look at it and it turns out, her flue was open.

When you have an open flue, it’s exactly like having an open window in your house. As she started to close the flue, soot and all kinds of other stuff started to fall down into the fireplace and on her. She powered through it and got it shut. According to Avista’s website, since she has a natural gas insert, she should not use a rooftop damper, which closes off the chimney from the roof. In fact, if you have a natural gas furnace that uses the chimney for its fumes, you shouldn’t use a rooftop damper, either. If you think it is safe to use one with your fireplace, make sure you work with a professional to choose the right one for your house.

In the next couple of weeks, I’m going to check back in with her to see if she notices any change in her comfort level, but I suspect she may notice there is no longer cold air seeping into her living room.

Lisa, an Avista customer, bought her 1910 house because she loved the old-world character, some of which doesn’t make her house very energy efficient.  Lisa is sharing her experience on taking some simple do-it-yourself improvements to inspire others to do the same. You’ll find her stories right here every Tuesday morning.

Read more energy efficiency expert advice.


  1. At Home with Lisa
  2. Energy Saving