› Chimney Dampers

Chimney Dampers

Stop The Fireplace Draft

Chimney dampers serve a useful purpose by acting as a "doorway" that opens and closes your chimney, and your house for that matter, to the outside elements. However most flue dampers that exist in traditional masonry fireplaces are made of cast iron and they aren't the greatest sealing devices.

If you stop and think about it, your flue opening acts like a horizontal window to the outdoors and if it doesn't close and seal well enough it can let a lot of heat and air conditioning go right out of the house.

Not only that but you might also feel those cold drafts as your home's heated air rises out through the chimney and cold air rushes in to take it's place. Sealing up your chimney flue is the best way to stop a fireplace draft and curb the escalation of your heating and cooling bills too. All it takes is a good chimney seal and there are several products that aim to do just that.

What You Should Know About A Fireplace Damper

The fireplace chimney damper serves as the gatekeeper for anything that can or might

attempt to pass from the fireplace to the outside of your home. Traditional masonry fireplaces usually have a cast iron damper located just above the firebox at the lower end of the chimney flue.

The problem with these kinds of dampers is that they don't seal well even when they're closed. This is because metal-to-metal contact between the damper plate and the frame makes for a poor seal.

Add to the mix some years of moisture and corrosion and perhaps some warping due to heat and that closed damper is likely to leak even more. This allows your heat and air conditioning to escape and invites cold drafts to flow down the flue.

To combat these problems and save on your heating and cooling bills you should invest in a damper that acts as a chimney seal. These are after-market chimney dampers that supplement the existing metal damper that's already in your fireplace.

Several different styles are available and they're classified by where they're installed in the chimney; either top mount or throat mount.

This simplified X-ray view of a fireplace and chimney shows the locations where each type of damper seals can be installed.

fireplace flue

Chimney Top Damper

Top mount chimney dampers are installed on top of the chimney and consist of a metal cap or gate that opens and closes. Most have a silicone rubber gasket that provides a tight leak-proof seal across the top of your chimney when the damper is closed.

Top mounted dampers are opened and closed by means of a steel cable attached to a lever that's fastened inside the fireplace. Moving the lever up or down opens and closes the damper seal.

Specific product examples include the Lyemance damper, Lock-Top and CHIM-A-LATOR®. The Lyemance and Lock-Top dampers are aluminum whereas the Chim-A-Lator is made from stainless steel. The All Season Control Cover is a painted or powder-coated steel chimney top damper. It doesn't have a rubber seal but is available in custom sizes.

Some products like the Chim-A-Lator Deluxe, Lock-Top II and Lyemance OPC are designed so that the damper is enclosed within a metal mesh guard. This prevents animals from being able to enter the chimney flue when the damper is open. In essence, they're a combination of an energy saving damper and a protective chimney cap.

Top mount chimney dampers cost about $150 to several hundred dollars depending on size, features and brand. This also does not include any installation costs.

Throat Dampers

Throat dampers differ from top mount dampers in that they are installed in the vicinity of the existing damper (just above or below). These aftermarket dampers are inflatable seals that form a "plug" in your chimney.

A throat damper is like a balloon that you inflate to seal up the flue and then deflate when you need to open it, whether for a fire or to clean the chimney. They're easily installed and removed and come with a "reminder device", like a tube or banner, that hangs down into the firebox to let you know it's there so you don't light a fire with the damper seal in place.

Users report mostly positive results although the key to its effectiveness is getting a size that fits your fireplace flue and installing it in a section with parallel walls.

Products include the Chimney Balloon® and the Fireplace Draft Stopper™. The Chimney Balloon comes in a wide variety of sizes and custom sizes can be ordered too.

Costs range from $40 to $60 however some larger sizes can cost up to $100.

Seals For Metal Fireplace Boxes

Lots of fireplaces installed in homes are pre-fabricated units made from metal, in contrast to built-in masonry fireplaces. Metal fireplace assemblies typically have vents in the front and the flue is a circular pipe that's attached to the top of the metal firebox.

The flue pipe is equipped with a flapper valve that opens and closes the flue by means of a chain. But because of wear, use or simply by design these kinds of flue dampers don't always seal as well as they should and allow cold air to leak into your home and heated air to escape. And depending on how the fireplace is vented to the outside, those vents in the front can let cold air sneak in when the fireplace isn't being used.

Products that solve these problems on metal fireplaces include magnetic covers for both the vents and the flue opening (more info on where to find them below). Prices range from approximately $15 to $50 depending on the particular product you buy.

Back To Page Section List

Choosing The Right One

Choosing the right chimney damper depends on what your objectives are and the problem you're trying to solve. If you're looking to stop a fireplace draft an inflatable chimney seal may be all that's needed. However if you're looking for something that will seal your entire chimney and prevent any pests from setting up a home in your flue, the top mount damper might be the best solution.

To that end, here are the positives and negatives associated with each type of damper. Inflatable damper plugs are typically intended for masonry fireplaces that have larger and sometimes angled dampers. Round magnetic damper/flue covers are intended for metal fireboxes and their smaller round flue pipes.

Inflatable Throat Dampers and Metal Flue Covers


Pros Cons

Easy to install and remove

Relatively inexpensive - you can purchase several of these for the cost of a chimney top damper

No need for professional installation

The inflatable ones many sizes and their design "self-adjusts" to the size of your flue

Magnetic flue covers for metal fireboxes make sealing the flue a quick and relatively easy task

The dangling banners or metal chains give you quick indiation that the flue is plugged and prevent you from starting a fire while they're in place

Forgetting it's in place before lighting a fire (you'd have to overlook the reminder strip to do this)

Doesn't prevent unwanted items (leaves, rain, critters) from entering the flue

Can be punctured though most are made to withstand the roughness of a typical fireplace flue

Inflating/deflating might become a hassle depending on how many times you use your fireplace




Chimney Top Dampers


Pros Cons

Durable devices made of aluminum/metal

Provides positive seal of entire chimney flue and keeps out the elements, drafts and animals

Products typically come with lifetime warranty

Cold air is kept out of the chimney so the home's spaces surrounding the flue stay warmer

Installation best handled by professionals unless you're pretty handy

Mechanical components might stick, freeze or corrode over time

Offers a slight restriction to the flue - chimneys with marginal draft may smoke more

More expensive than a balloon-style damper



In the end it's really about how much you want to spend to eliminate problems like drafty fireplaces and higher utility bills. If you have several masonry fireplaces the more economical solution might be to purchase the inflatable chimney dampers, avoiding the more costly route with the chimney top varieties.

Also, if you already have a chimney cap that has some form of protection from animals as well as the elements, the inflatable draft stopper might be the simplest solution.

Keep in mind that regardless of which way you go you'll still need to open the flue before a fire. That means deflating and removing the inflatable dampers or reaching into the firebox and manually opening the chimney top damper.

Back To Page Section List

Where To Find Them

These chimney dampers aren't hard to find though your first step should be to decide who's going to do the installation.

An inflatable chimney damper is something you can easily do yourself and you can find them from various sources online. Just search using keywords such as "inflatable chimney plug", "chimney balloon" or "fireplace draft stopper".

The chimney top dampers are another story however and while they can be installed by someone with the right tools and skills, it's not for everyone (particularly if you don't like heights).

Businesses that specialize in chimney repairs and supplies can supply you with a chimney top damper and install it too. Keep in mind you'll need to pay for the labor to install the damper in addition to the damper itself. Do a local online search for "chimney supplies" or "chimney repair" and add your city or town to the search term. Some chimney sweep businesses also install these types of energy saving dampers.

If you're going to install it yourself you can buy chimney top dampers from online chimney supply sources or possibly from local chimney repair businesses.

Back To Page Section List

Where Would You Like To Go Next??...

Putting The Stone On The Fireplace - Speaking of chimney dampers, in part 15 of the 'Real Life Remodeling Adventure' the stone gets put on the fireplace. Did we go with real stone or faux stone?




survey page ad