24 Aug #99: What Chimney Plug Do I Use if I have No Damper?
Fireplace #99: Wide-Open Smoke Chamber and Flue, No Hardware
These fireplaces with no damper or hardware of any kind are usually quite old. They represent a worst-possible-case-scenario as far and heating and cooling loss goes. Once you get this plugged you will notice an immediate difference in the home.
You can basically take your pick from the chimney plugs we offer. You just need to select the height you want to plug the flue, and measure length and width of that location (image 99-1)
Here are the advantages of each:
- The Chimella is the easiest to take in and out, and is durable. If you order a Large Chimney Umbrella you can fill a flue hole that is 19″x27″ or less. If you plan on using the fireplace, this is a good option. (image 99-2)
- The Flueblocker comes in many sizes. So you can select one that is slightly larger than your measurements and press-fit it in place. This wool pad offers a tight seal and insulation properties. This is good if you prefer a fix it and forget it solution. (image 99-3)
- The Chimney Balloon provides a tight seal and sound buffering capability. It is an inflatable, so it is less durable that the other options. The Chimney Balloon is about 10″ tall when inflated. So you must install it low in the flue where the walls are parallel. so it can grab the walls. It does particularly well at stopping odors and bugs. (image 99-4)
What if I see a cable or chain coming down the chimney?

99-5: Chimney Top damper cable
If there is a cable or chain coming down your chimney (image 99-5) that is a different kind of application called a chimney top damper. You should read the article on that fireplace application.