Q: I have a top sealing damper, and I still get a draft from my fireplace. It cost me $550 to get the chimney top damper put on my chimney and it only half solved the problem. Will a $50 Chimney Balloon stop the draft that is still there? – DP

A: DP – I remember talking to a Chimney Balloon customer from Detroit on the phone for nearly one hour regarding this very same issue. The result of our conversation was that the lock top damper and Chimney Balloon damperwork well together. The Locktop (otherwise known as a top sealing damper) and Lymance dampers keep birds and animals out and the Chimney Balloon stops the convection draft and chimney odor. You can use one or the other alone, but using them together is a very effective approach at eliminating draft, odor and other infiltration. This is an issue that we have addressed before in the Chimney Balloon Blog, but it is worth revisiting since it is a common question.

The light draft you are experiencing with the lock top or lymance damper is very common with top sealing dampers. When you seal a chimney at the top you are making your chimney into a large stopped tube that still has to be filled with warm interior air, so your furnace heats that air and it rises up into the chimney. Over time this air cools against the cold metal of the top damper and starts to sink. When it sinks it creates a light cool draft sensation in the hearth or the opening of the fireplace. This makes it feel like the damper is letting in cool air.

If you install a Chimney Balloon low in your fireplace you will eliminate this cold draft sensation. You may have concerns about the lock top or lymance damper chain or cable interfering with the Chimney Balloon, but we have found most of the time the Chimney Balloon will form around this chain or cable without a problem. However, there are a few things to keep in mind about the chain or cable for a lock top damper.

In the picture above the top sealing damper cable as a very faint line just to the left of the Chimney Balloon valve in the picture (see the orange arrow). You can also see that the Chimney Balloon has folded around and enveloped the cable. You see the cable runs along the edge of the metal damper there as well. In this application, the cable is getting frayed over time as it rubs up and down against the metal edge of this damper opening. That frayed section of cable has little needle-like protrusions and a flat side that is like a saw blade in roughness. Also, notice that the Chimney Balloon is tight like a drum. It is probably a little two tightly inflated.

  1. In this type of application wrap packaging tape around your chimney top damper cable in the area, the Chimney Balloon will come in contact with it. This will keep the flat sharp end of this cable from cutting the balloon. Also, do not actuate the cable by opening and closing the damper while the Chimney Balloon is in place. Remove the Chimney Balloon before you move the cable.
  2. When the Chimney Balloon is installed do not fill it drum tight full with air. Leave a little springiness in it.
  3. Also, purchase a Chimney Balloon that is a little oversized to allow for the extra material to envelop the cable. Two or three inches extra in length and width should give you what you need. In this photo example, a 33×12 could have been used normally, but they bought a 36×15 to get it around the damper cable.

If you take these prescribed precautions your Chimney Balloon will work just fine with your top sealing damper and stop the cold draft. – Jason