What’s the Difference Between a Chimney Cap and a Damper?

So, you’re wondering about the difference between chimney caps and chimney dampers? There’s a big difference, but as per usual the confusion is in the use of the terms.

Chimney Dampers

A damper is a device which slows down the flow of smoke. In the case of fireplaces, it also slows down the heated house air from going up the chimney. This is the main purpose of a fireplace damper.

Chimney Cap

chimney cap

Stainless Steel Chimney Cap

A rain cap, a chimney cover or an animal guard is something that mounts over the top of the flue. It helps to keep rain and animals out. While you can get a cover made out of ordinary steel, don’t. You absolutely want a stainless steel chimney cover because the other ones rust. A cap also usually has some sort of screen to prevent birds and animals out as it keeps the rain out.

A chimney cap does not stop the flow of air/smoke in the flue. There is nothing to operate; they just sit on top of the chimney and keep rain out. Caps are usually called chimney caps and that pretty well sums it up for them.

Top-Sealing Dampers

So let’s talk about Top-Sealing dampers. These dampers do in fact mount to the top of the chimney; in this way they are the same as caps, and this of course is where the confusion comes from.

The top-sealing damper is a device with a base for mounting on the flue tile and it has a lid which lifts up and down to block smoke, which also helps to keep rain out. The lid is held up by strong springs and it’s natural position is open. The lid has a stainless steel cable attached to it which runs through the chimney and mounts to the side wall of the fireplace below.

Within the fireplace, the damper cable has a handle and the mounting bracket is made in such a way as to hold varying degrees of openness. This openness ranges from fully open to completely closed. To operate the damper just grab the handle and pull it into the position you want it to be in.

Is there any further confusion about chimney caps or chimney dampers? Share your responses below.

4 thoughts on "What’s the Difference Between a Chimney Cap and a Damper?"

leanne harper says:

I have removed a freestanding gas heater (big and ugly, but effective) from the hearth in front of a fireplace. There is currently a length of flexible hose the same size as a dryer-vent that runs up into the chimney and a separate round steel piece with a knob that is unattached to anything. The floor of the firebox seems intact. there is a space below it which is open to the room and looks like it should be covered with something – a grate maybe. There is also an open space immediately above the firebox.

What kind of professional should I call to find out how to return this fireplace to working order? I don’t see anything online that seems especially useful in this regard.

Dale Howard says:

Leanne,

A Certified Chimney Sweep should be able to help you out. I can tell you that the dryer-vent sized hose the liner for the gas appliance. Not sure I picture all the rest of that but either a Certified Sweep or the people at a hearth store (who also make house calls) should be able to assess the situation for you.

Good luck and stay warm!

Debbie says:

Are fireplaces dampers meant to only be all the way open or all the way closed. If so this makes no sense to me please explain.

High's Chimney Service Inc. says:

Good question. Most people do in fact open or close it completely. But the original idea is that you’ll adjust the opening as appropriate for the smoke. The thought being that you’ll keep more heat in the house. How that works out in practicality is another fair question. But yes, feel free to adjust the damper opening to any width you think is appropriate.

And stay warm!

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