Sunday, August 30, 2009

Insulate your unused chimney

Some years ago we had a fireplace, but we never used it that often, and there was always a cold draft from it when it was not in use. So we sold the fireplace (and got space for a home movie theater instead..) and sealed off the chimney. Much of the draft was gone, but last winter I noticed that the chimney was still very cold when touching it. Both on the ground floor, but even more on the first floor. No wonder when all that cold outside air fills the entire chimney.
So in preperation for this winter I made a simple unused chimney insulation. I used a total of seven plastic bags, each filled with some insulation material. After tieing the top of each plasticbag, I connected them all together with a string. Using a long stick a pushed the first one about 4 m ( 12 ft) down the chimney.

Then I pushed the next one a little bit shorter, and the next even shorter, and so on until the last one finshed it off right at the top of the chimney. This should defenitely slow down any cold air trying to go down the chimney this winter. Should we decide to get a fireplace in the future I can easy pull all the insulation bags out of the chimney using the string that interconnect them all.

Summary in Norwegian: En ubrukt pipe er en kald pipe. Du kan isolere pipa ved å trykke plastposer med isolasjon ned i pipa. Hvis du forbinder dem alle med et tau, så går det greit å få dem opp igjen hvis du skal bruke pipa igjen.


Jonathon said...

Thanks. I had a similar idea - using only one bag - but your method is better. Even if my one bag effectively stops cold air from entering the chimney from above, the other bags will provide much-wanted wall insulation.

Jonathon said...

Hmmm, I just read: "If you do not use your fireplace, you may want to seal off and insulate the chimney. Be sure, however, to provide some ventilation for the flue. If you fail to provide ventilation, condensation will form in the chimney." ( Do you know how I could do that without letting the cold air in?

Svein* said...

Hi Jonathon,

You are referring to the last section of . When warm, moist air enter any place cold, condensation will form. So I agree there is a risk for this. If the chimney is seal off completely on the inside, this should not happen. With just one bag of insulation last year I did feel some draft coming out behind my slightly imrovised cover that I have used to seal off the chimney on the inside. This year I feel no draft. I will keep an eye on it. I guess one result from condensation could be some bad smell, but that has not been a problem so far. We will see. So I guess my advice will be to seal the inside completely, and make sure the bags in the chimney are not completely air tight which will allow moist air to escape.

Jonathon said...

Thank you.
I have a 6-centimetre-thick foam board underneath the "damper", above the fireplace, at the entrance to the chimney. I will add lots of caulking where the foam meets the brick, so warm, most air does not enter the chimney. And I suppose I'll allow the insulation bags to be less than 100% air tight.

Roselyn Withem said...

How is everything going now? Have you sealed the chimney? Why don't you try roofing insulation? If you still have that chimney, then try both chimney insulation and roofing insulation so you can be warmer during the winter.

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