chimney plug
Is there an airtight 6″ diameter chimney plug that you would recommend for the off-season, for energy-saving purposes? Currently I’m using a Cherne test plug but it’s not a perfect seal and it’s hard to place perfectly.
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In an old house I had, the tightest, and most cost effective solution was to take a garbage bag, cut a few pieces of rigid insulation to sort of fill up most of the gap and put in bag, stuff it up there with the open end of the bag towards the bottom, and start spraying canned spray foam into it. Fills the gaps, easy to remove if you make sure it does not get into any kind of inverted bell shape, and effective.
I have used the same approach as CL, basically stuffing a plastic bag with wadded up newspaper and pushing it up the chimney. I've also used inflatable draft stoppers by Battic.
Regardless of approach, make sure you leave a very obvious visual reminder that the chimney is blocked off, so that the next user removes the plug before lighting a fire.
Andrew C,
UI comment: Stuff the plastic bag with yellow safety chain, leave a few feet dangling down into the fireplace, then foam it together. Now you have both a handle and a warning.
I've had good luck with Lock-Top dampers, which are tightly-sealing chimney top dampers that are operated by a metal pull chain. You get year-round savings without the hassle and mess of the garbage bag method (which I've also used).
A chimney top damper makes a lot of sense, I'd prefer that approach if I have the situation again.
Keeping critters out is part of the issue, especially if the building is unoccupied. True story: when I flushed a toilet at a cottage last week, a live red squirrel (covered in muck so that it was black) swam up out of the toilet. I only had a toilet brush to fend him off and I couldn't push him back down from whence he came. (insert long story here...) The squirrel ended up exiting through the front door of the cottage. I've since put some hardware cloth over the vent pipe outlet on the roof.