After our recent energy audit found drafts in a number of places in our house, and even though the damper was closed, one of the biggest was the chimney — the auditor recommended a “chimney balloon“. It’s a good, simple product, and I can tell that it works beautifully. The maker claims that you can save almost twice it’s cost annually: a good way to reduce heating bills.
The chimney balloon is an inflatable bag, available in various sizes to fit inside your chimney. A tube and valve on the bottom allows you to inflate it so that it conforms to even the roughest, oddest shaped chimney interiors. The inflating tube is detachable, so there’s nothing visible when installed. The balloon is made of a tough, durable plastic. It can be easily removed as needed (but don’t forget to before lighting a fire!) and just as easily reinstalled. The cost is under $50, and their web site has a lot of great and helpful information on how to choose the right size.
I can tell that the chimney balloon works because it has solved an annoying problem for us already this summer: during cooler evenings, we get fresh and cool air into the house using our whole-house fan. If we don’t have enough windows open, the living room would have a smokey smell, as the fan would draw air in through the chimney. After we installed the Chimney Balloon, the problem is solved, and we get fresh air in the house.
As a result of an inadvertent slip, I did manage to put a small puncture in our chimney balloon (don’t ask: I’ll just say it was not a very clever move on my part, and involved a razor knife :-). After a quick look around on their site, I found good instructions for repairing it: a patch with packing tape did the trick and it’s as good as new.
It’s hard for me to quantify the savings in heating (and cooling) one could expect from this product. Based on our audit, we’re expected to save about $350 per year on our heating bill after completing the various air sealing projects identified. It’s pretty clear, just from walking around with the inspector while the blower-door sucking air out of the house during the test that the chimney, even with damper closed, was one of several large sources or air leakage. Perhaps if it accounts for 10% or 15% of the fixable leaks, the cost of the larger sized chimney balloon we needed should be paid for in a year or less. This seems to be backed up by independent testing reported by the seller which suggests savings of more than $100/year (for a house in Minneapolis). At a cost of under $50, it’s a quick payback on fuel alone.
Another solution for blocking chimney drafts is to install glass doors over the fireplace opening. They are far more expensive, however (around $250 and up), and a bit of a chore to install, especially if your fireplace opening is not relatively flat. The tests I note above suggest that the chimney balloon is a bit more effective than glass doors, too, although I suspect either makes about the same difference.
This is a small expense and small effort that can save you a lot of money over the years, and reduce your carbon footprint a little bit.