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February 12, 2012
We're always on the lookout for clever, easy ways to make your home more comfortable, less drafty and more energy efficient. A chimney balloon is one of these.
Here's the scoop: a lot of homes have chimneys that are rarely used. Maybe you have a fire in the fireplace once in a while, but typically it's reserved for special occasions. The rest of the time the chimney, which is designed to effectively remove smoke and unsafe gases from your house, keeps removing air from your house, but it's not the unhealthy air that a fire creates -- it's the warm air inside your home that you're paying to heat with your home's central heating system.
While closing a damper does make a small difference, dampers are made out of metal. They're not typically air tight, and warping over time makes them even more prone to air leakage. A chimney balloon does what a damper doesn't do, by completely sealing off the fireplace and preventing any warm air from escaping your home.
In addition to keeping your house warmer, chimney balloons serve some other pretty nice functions as well:
The warm air escaping up your chimney needs to be replaced somehow, and it's typically replaced with air seaping into your house through air leaks in your basement, poorly sealed exterior walls, and around windows and doors. The air movement created in this process is what we know as a draft. A drafty house in the winter is no fun.
Lower your heating bill.
Of course, all the heated air that's escaping up your chimney is air that you paid good money to heat. Think about it: every minute that your heating system is turned on, your hard-earned dollars are literally going right up the chimney. In this economy, that's no good at all.
Keep out the critters.
Another downside of a leaky chimney is that bugs, bats, birds and who-knows-what-else are free to climb right down into your house. Especially if your damper is particularly warped, leaving gaps on either side, you're welcoming some unwanted guests into your home. By sealing the chimney off completely, a chimney balloon will prevent uninvited guests from entering your house. (Saint Nick, of course, is magic, and should have no trouble temporarily removing the chimney balloon to bring your toys on Christmas, so don't worry about that.)
We asked energy auditor and home inspector DeWitt Kimball, owner of Complete Home Evaluations, what he thought about these things. (He's one of the best energy auditors in Maine, so we trust him.)
Here's his response:
I recommend the balloon to everyone that has a wood burning fireplace. Fireplaces are made to remove smoke and heated combustion gases from a home. Removing heat occurs even when the fireplace is not in use.
The metal flue dampers have a very poor air sealing and warm air sneaks by them and exits the home. The chimney balloon completely seals the flue. When I do a blower door test and depressurize a home air blasts by closed flues and will blow ashes into the living space.
This does not happen when a balloon is installed. Virtually no air gets past the balloon.
They are also easy to install and remove which increases the chance that they will be used.
Be sure to measure your chimney before you purchase a chimney balloon, but you do have some slack: up to 6 inches on either side larger than your chimney size should work fine. Also make sure to leave the balloon tag in the fireplace so you don't forget the balloon is up there.
Happy hump day!