Fireplace Damper

Fireplace Dampers (Everything You Need To Know)

In Chimneys, Indoor Fireplaces, Wood Burning Fireplaces, Wood Burning Stoves by James O'KellyLeave a Comment

What Is A Fireplace Damper?

A fireplace damper is a device that can be manually opened or closed with the purpose of allowing gases and other byproducts from a fireplace to be safely vented from a building when open, but to also prevent air from escaping the building when a fireplace isn’t being used.

Fireplace dampers can typically be found at the base of a chimney, at the top or a chimney or at the base of a flue. Dampers are usually made out of metal or ceramic to allow them to withstand the heat of the fires and the resulting smoke, air and gases.

An open damper allows smoke and other harmful gases produced by a fire to escape from the fireplace, and to also provide further air from the outside to help keep the fire going. If the damper is closed when a fireplace is in use, smoke and gases will enter into the room, which can be a potentially serious health hazard if not dealt with quickly.

An open damper can cause a draft within the chimney and heat loss from a home, and so a closed damper helps to keep in warm air during the winter, and cooler air during the summer

What Is The Definition Of A Fireplace Damper?

Dictionary.com defines a fireplace damper as:

‘a movable plate for regulating the draft in a stove, furnace, etc.’

Why Is It Called A Fireplace Damper?

The Oxford English Dictionary defines the word damper as:

‘a thing that has a subduing or inhibiting effect.’

In this case, the dampening effect of a fireplace damper is to control:

  • The flow of hot air, smoke and gases from a fire in a fireplace or stove into a chimney or flue.
  • The flow of air down into a fireplace or stove from a chimney or flue.

By controlling how open or closed a fireplace damper is you can inhibit the flow of any air, gas and particles through that damper.

Types Of Fireplace Dampers

There are three main types of fireplace damper:

  • Fireplace throat dampers
  • Chimney cap dampers
  • Flue dampers

I explain below where you can find each of these types of dampers in a fireplace.

Where Is A Fireplace Damper Located?

A traditional fireplace damper will usually be positioned just inside the base of the chimney (called the ‘throat’ of the chimney), at the top of the fireplace. This allows the damper to be hidden from away from view, but also easily accessible from within the fireplace.

Here’s what you can expect a throat damper to look like:

Fireplace Damper
A damper located at the base of a chimney, just inside the top of the fireplace

A damper may sometimes be located at the very top of your chimney, known as top-mounted damper or a top-sealing chimney damper cap.

A damper can also be located at the base of a flue, located just above a wood burning stove or other form of fireplace stove that utilizes as flue.

Here’s where you can expect to find the controls for the flue damper:

Flue Damper Controls
The handle to control the damper located in the flue, just above the wood burning stove

What Is A Chimney Damper Used For?

A damper located within a chimney is traditionally used with a wood burning fireplace and can be found located just above a fireplace or at the top of a chimney, but why would you use a fireplace damper?

A fireplace or chimney damper is used for:

  • Helping to control the efficiency, and reducing the intensity, of a fire in a fireplace by partially closing off the damper.
  • Ensuring that waste smoke and gases from a fire are vented from your home when the damper is open.
  • Preventing warm or cold air from outside from entering a home through the fireplace when it’s not in use and the damper is closed.
  • Preventing warm air or air conditioned air from being lost out of the chimney when the fireplace isn’t in use and the damper is closed.
  • Preventing rain, animals and debris from entering the fireplace via the chimney when the damper is closed.

What Is A Flue Damper Used For?

A flue damper works in the same way as a chimney damper but is slightly different. They can commonly be found with wood burning stoves.

A flue damper is used for:

  • Reducing the draft up the flue by partially closing off the damper.
  • Helping to control how quickly the fire burns through the fuel.
  • Helping to reduce the amount of heat that is lost up the flue.
  • Helping to put out a fire in a wood burning stove in conjunction with using the stove’s air vents.
  • Helping to prevent rain, animals and debris from entering the stove via the flue when the damper is closed.

A closed door on a wood burning stove prevents warm air from leaving a home and cold air from entering. A flue damper therefore doesn’t typically need to be closed like a chimney damper when the stove isn’t being used.

What Is The Difference Between A Flue And A Damper?

A flue is a pipe that extends out of a fireplace to the outside of a house, to vent any waste gases, smoke and small particles from a fire that would have otherwise been released into the home.

A damper is a device located inside the flue that helps to control how quickly warm air, waste gases and smoke are released from the fireplace during a fire, while also helping to reduce the inflow of cold air from the outside while the fireplace isn’t in use.

Does A Fireplace Need A Damper And Is It Necessary?

A fireplace does not specifically need a damper to work, and having one isn’t necessary in order to have a fire in your home.

It can sometimes be an advantage to have a damper installed within your fireplace or stove, but it isn’t essential.

The main reason you would want a fireplace damper is to help prevent the warmth from leaving your home during the winter months, especially when the central heating is on.

A damper can also be useful in the summer months. A closed damper will prevent air conditioned rooms from venting the cooler air out of your home.

Another advantage would be if the diameter of the chimney is too large for the size of the fireplace. A partially closed damper helps restrict the size of the chimney and therefore the amount of draw on the fireplace from the chimney. Too much of a draft and all of the heat can be lost up the chimney, and the fire will burn through the wood more rapidly.

On the other hand, not having a damper in your fireplace can be a good a thing in some circumstances. It can prevent the potential for a fire to be started in your fireplace when forgetting that the damper is closed. This would cause smoke and gases to pour out into the room rather than up this chimney (this is why some people buy damper signs to let them know whether the damper is open or not).

An open wood burning fireplace will usually work just as well whether a damper is installed within the chimney or not. We have don’t have a damper in our chimney and we regularly have fires in our wood burning fireplace throughout the winter months without a problem.

Do All Chimneys Have A Damper?

Not all chimneys or flues have a damper. Open fireplaces can usually be found with damper located within the upper part of the firebox. It’s common to find a damper as part of an open fireplace, but in some cases there may be no damper at all.

It’s possible that you have an old fireplace with no damper, just like we do. There’s no damper installed anywhere within our fireplace, or further up the chimney.

Here are a few photos I took of the open fireplace in my living room, showing the top of the fireplace and looking up the chimney from directly inside the fireplace:

Chimney From Fireplace
Looking up the chimney from my living room fireplace
Looking into the top of my fireplace from the fireplace opening

You can see that there’s no damper installed within my fireplace. And yes, it can get very cold in my living room in the winter!

When we bought our house in 2016, the fireplace was open and empty. As far we know, the fireplace has always been an open fireplace, and there is no reason to believe that a fireplace insert was ever put in.

It may be the case that our fireplace once had an insert and that the original damper was removed, or it might be that a damper was never installed when the house was built.

If you know why my living room fireplace doesn’t have a damper then please let me know in the comments below!

Does A Wood Burning Stove Need A Damper?

In many cases a wood burning stove doesn’t need a flue damper, but depending on the situation it can be beneficial to have one.

A flue is required to suck any smoke and gases produced by a fire out of a wood burning stove, and to also provide safe passage for the smoke and gases out of your home. Each wood burning stove is designed to work with a specific size and diameter of flue.

A damper located in a flue can be used to throttle the effectiveness of the draft on a wood burner. Too much draw on the stove and much of the heat produced can be lost out of your home.

By slightly closing off the damper you can create the required draw and ensure that the stove reaches its maximum efficiency for releasing heat. By slowing down how quickly gases leave your stove, you and help provide secondary burn of these gases and allow your stove to produce even more heat.

A wood burning stove damper can be used to alter the draw on the stove:

  • During periods of hot or cold weather.
  • During periods of high or low pressure.

Whether a wood burning stove needs a damper or not depends on a number of factors, but most importantly whether your flue needs to be restricted in order for your wood burner to be working to its potential. If the size of the flue is too small for your wood stove then adding a damper can make the situation worse however.

As every single situation is different, it’s worth talking to a local professional to get their views on whether your new or existing wood burning stove needs a damper.

My dad doesn’t have a damper on his wood burning stove flue, and it works effectively and efficiently without one. The right size chimney liner was installed at the same time as the stove, and was designed to ensure that there was sufficient draw on the fire. Many newer stoves are provide enough air tightness that a damper isn’t required.

My dad’s wood burning stove flue doesn’t have a damper

How To Use A Chimney Damper

This section is on how to use a chimney damper associated with an open fireplace and a chimney. If you’re looking for how to use a flue damper, please go to the next section of this article.

Chimney dampers are objects that need to be operated manually. It’s therefore important to understand how they work so that you don’t start a fire when one is closed shut, as it would prevent much of the smoke and gases from leaving your home.

How Does A Chimney Damper Work?

To allow dampers to be open or closed, they are most commonly found with a handle, rotary style screw or pull chain.

Dampers with a handle can also usually be found with latches on the handle to enable them to be partially opened or closed at certain angles.

This allows the efficiency and intensity of a fire to be controlled. By leaving the damper partially open, you can learn to control the fire just like you would by adding more logs or providing more gas to the fireplace, while also allowing any smoke and gases produced by the fire to escape from your home.

Up to 80% or 90% of heat generated in a fireplace can be lost up the chimney rather than being used to heat your home. By adjusting the damper you can help reduce this heat loss.

[To prevent any smoke or gas from entering your home, the damper should always be fully open when starting the fire, and only close the damper when the fire has completely died out and the ashes are cool]

Is My Chimney Damper Open or Closed?

If you’re unsure how to tell whether your fireplace damper is open or closed, follow these simple steps. Be sure to only check when both your fireplace and chimney are cold.

1) Visual Inspection

Position yourself just outside of your fireplace and lean in under your chimney. You may be able to see an unflattering metal thing just within the opening of the chimney or flue. If you can see up through the damper to your chimney then you know that the damper is open. If you can only see a metal plate then your damper is closed.

If you can’t see in your fireplace because it’s too dark, try to find a flashlight. I used the torch function on my phone to allow me to see up my chimney, and used the flash on my phone camera take the pictures you can see of my chimney in this article.

If you have a top-mounted damper then you probably won’t be able to see it from the inside of your home. Have a look outside at your chimney to see if you have a metal object at the top of your chimney, which may be a sign that you have a chimney cap damper.

If you have a chimney cap damper then you’ll need to look for the controls in your fireplace to operate the damper.

2) Look for the controls

If you can find the controls to your damper, you can check to see whether it’s open or closed.

If you have a traditional damper that’s located at the base of the chimney, there should be a metal handle with a latch or rotary style screw, which usually found in the centre of the unit, on the opening side of the fireplace.

Typically, the further away from you the handle or level is, the more open the damper is. If you can’t move the handle any further away, then the damper may be open. If you can pull the handle towards you then you may be closing the damper. Some dampers also work in reserve; pulling the handle towards you will open the damper, while pushing it into the fireplace will close it.

Other throat dampers can also be opened and closed by moving a lever to the left or right. A lever pushed to the left will mean a damper that is closed, while a lever pushed to the right will signify an open damper.

If you have a damper located at the top of your chimney, known as a top-mounted damper, you should have a chain on the inside side of your fireplace. A chain that is hooked onto the side of the fireplace wall surround is usually a sign that the damper is closed. A chain that is hanging freely and not hooked to anything is a sign that the damper on the top of your chimney is open.

It’s always worth getting professional advice before using your fireplace if you’re not sure whether your damper is open or closed.

3) Check for a draft

Simply place your hand at the top of the inside of your fireplace. Can you feel a draft? It’s probably a sign that your damper is open.

You can also take a match or rolled up newspaper and light it, and place it near the inside top of your fireplace. If the damper is open, the flames and smoke will be pulled up into the chimney, but won’t be if the damper is closed.

4) Listen out

In my living room fireplace I can hear the sound of the air moving within the chimney, as well as noises from the cars driving past outside. It’s faint, so the room has to be quiet, but I think it can be another way to tell if your damper is open, especially if you don’t have a light source available to look up your fireplace.

Many chimney dampers don’t close with a tight seal, and so hearing the movement of air within your chimney may not always give a good indication of whether your damper is open or closed.

It’s definitely not a good idea to start a fire to see if your damper is open because, if it‘s not open, you’ll have all of the smoke and gases from the fire entering your room.

If you can’t find any sign that you have a damper then your chimney and fireplace many not have one (ours doesn’t). It’s important to seek the opinion from a professional to make sure that there isn’t a closed damper that’s hidden that would prevent harmful gases and smoke from leaving your home during a fire.

A chimney sweep will be able to confirm whether your chimney has a damper or not, and how to open or close it. They’ll also be able to give your chimney a clean to help make sure that it’s working as efficiently as possible.

How To Open And Close A Fireplace Damper

Check to see if your damper is already open by following the steps above.

If you have a traditional damper located within the throat of your chimney, find the controls to your damper by looking under the top of your fireplace. You may have a lever of handle that is forward operating or sideways operating, or a screw-type handle.

For a handle with latch control, lift the handle and push it away from you as far as possible to fully open the damper. Drop the handle back down in the latch to prevent the damper from closing again. To close the damper, simply reverse the process; lift the hand and pull it towards you as far as it will go.

Other dampers will work in reverse; pulling the lever towards you open the damper, while pushing it back into the fireplace will close it.

Here’s a video showing how to open and close a fireplace damper with a forward operating handle:

Some dampers have a lever handle that operates sideways to open and close the damper rather than forwards and backwards.

The video below shows how a damper level can be moved to the right to open and to the left to close:

For a rotary style screw control, turn the screw handle clockwise to open the damper, and turn it counterclockwise to close the damper.

If you have a top-mounted damper, find the chain hooked on the side of your fireplace and unhook it. The chain should spring up as the damper opens, and you should start to feel a draft. To close the damper, put the chain back down and place it back onto the hook, making sure not to let the chain move up allowing the damper to open again.

If the chain doesn’t spring up when let go then there may be a problem with your top-mounted damper. You should consult your local chimney sweep before starting any fires in your fireplace.

Here’s a quick video showing a chain in a fireplace for a top-mounted damper and explaining how it works.

How To Use A Flue Damper

This section is on how to use a flue damper associated with fireplace stoves and flues. If you’re looking for how to use a chimney damper, please go back to the previous section of the article.

How Does A Flue Damper Work?

A flue damper is usually found just above the fireplace stove, at the base of the flue, but may be located further up the flue.

A flue damper needs to be manually operated to open or close, and so there will always be a set of controls located on the flue operate the damper.

By closing the damper, you are preventing the majority of air passing through that point inside the flue, in either direction. With the damper open, air can flow freely up the flue when having a fire, and even down the flue when the fireplace isn’t in use.

It’s important know whether you have a damper, where it’s located and how it’s operated so that you can ensure the damper is safely open every time you have a fire in a wood stove.

Is My Flue Open Or Closed?

If you’re unsure whether the damper on your flue is open or closed, you can follow similar steps as for a chimney damper by visually inspecting and listening out for signs that your damper is open or closed.

It’s easy to forget which way you need to turn or slide the damper to open it, as in many cases you can’t actually see the damper opening or closing inside the flue, but flue dampers can typically be turned in any direction to open and close.

A flue damper handle located on the outside of the flue will typically be in line with the damper itself located inside the flue.

If your flue is going straight up vertically, a handle that is horizontal typically means that the damper is also horizontal, and therefore in the closed position. If the handle is in a vertical position then this typically means that the damper is also in a vertical position, and therefore open.

Be sure to only check your damper when both your stove fireplace and flue are cold.

If you’re still unsure whether you’re flue is open or closed, follow the steps below:

Visual inspection of the controls and stove:

  • Look at where your damper controls are located to see whether you can see which way the damper is opening or closing as you move the controls.
  • Look inside the stove fireplace too see if you can see more light in one damper control position compared the other.

Check for a draft:

  • Open the stove door and place a lighted match or lighted piece of rolled up newspaper near the inside top of the stove. If you can see the flames and smoke being pulled up the flue then it’s a sign that your damper is open. A closed flue damper won’t be able to suck the flames and smoke from the stove as effectively.

Regulations require that flue dampers never quite fully seal the flue and so you will always get a small amount of airflow through the damper even when it’s fully closed.

How To Open And Close A Flue Damper

It can be confusing as to whether a damper can be opened or closed by turning it to the left or right. Every fireplace and flue is different, and there can unfortunately never be a ‘right’ and ‘wrong’ way to open and close the damper located in a flue.

The position of the damper handle will typically tell you in which direction the damper inside the flue is facing:

Horizontal handle = horizontal damper = closed position

Vertical handle = vertical damper = open position

A flue damper doesn’t just have to be located in a vertical or horizontal position. Flue dampers can typically rotate 360 degrees in either direction, and so you can put the damper in a completely closed position, completely open position, or anywhere in between.

Flue dampers can therefore typically be opened and closed by turning the damper controls either to the right or to the left.

By partially closing off a flue damper you can help to control the heat loss from a wood burning stove, while still allowing waste gas and smoke leave your home.

Here’s a good video explaining how to open and close a flue damper:

Fireplace Damper Parts

Fireplace Damper Plate

A fireplace damper plate is the piece of metal or ceramic that opens or closes to allow or prevent air to pass freely through a chimney or flue.

A damper plate located at the throat (base) of a chimney is usually rectangular in shape, and is held in place within the chimney by a surround.

A damper plate located at the top of a chimney (within a top-mounted damper) is usually square in shape and spring loaded to open or close via a pulley chain, with the chain handle to control the damper located within the fireplace.

A damper plate located within a flue is typically circular in shape to suit the diameter of the flue, and is held in place by a metal pin going through the flue.

Fireplace Damper Handle

A fireplace damper handle, also known as a knob, is the piece of the damper that is used to control the opening and closing of the damper.

For a traditional throat damper, it’s usually operated via a handle with latches to be able to leave the damper partially open, or via a screw handle system that opens or closes the damper depending on which way it’s turned.

For top mounted dampers, the handle can simply be the end of the chain that hangs down from the top of the chimney. It can be hooked onto the side of the fireplace when pulled down to close the damper and ensure it remains closed.

The handle on a flue damper is located on the outside of the flue, and is typically simple enough in design for the user to be able to turn the damper inside the flue with ease.

What Is A Fireplace Damper Clamp?

A fireplace damper clamp, also known as a damper stop, clip or lock, is a device that clamps to a fireplace damper to ensure that the damper always stays in a completely open position and can’t fully close.

Fireplace damper clamps are typically used for gas fireplace inserts or gas logs sets where it’s required for the damper to be in fully open position at all times. A damper does not need to be used to control a gas fireplace fire, and it can be very dangerous to use a gas fireplace with a damper in the closed position.

Burning gas releases carbon dioxide, and potentially carbon monoxide if the gas isn’t being burnt properly. A closed damper can prevent these gases from leaving your home, and so a damper clamp is a safety feature to stop this from occurring.

Fireplace Damper Questions

Should A Fireplace Damper Be Open In Summer?

A chimney damper should be left closed during the summer months when the fireplace isn’t being used as often. A damper that is left open typically won’t help to cool down your home in warm weather, and so it’s not necessary to leave your damper open in the summer.

A closed damper helps to:

  • Prevent air conditioned air from leaving your home.
  • Water getting into your fireplace during periods of wet weather.
  • Prevent any unwanted smells from chimney from entering your home.
  • Stop animals, leaves and debris from coming into your fireplace.

Should A Fireplace Damper Be Open All The Way?

A fireplace damper should always be open all of the way when starting a fire, and usually always open throughout the length of the fire.

A flue damper should be opened all of the way when opening a stove door to add further fuel to the fire, to help prevent any smoke from pouring out of the stove and into the room.

A fireplace damper must always be open all of the way when using any form of gas fireplace.

A chimney or flue damper doesn’t always need to always be open all the way when burning wood in your home. Depending on the situation, you can slowly close down the damper to help limit how much heat is lost from the fireplace or stove, while still being able to vent waste gases and smoke.

Should A Fireplace Damper Be Closed When Not In Use?

A fireplace damper doesn’t have to be closed when not in use, but when closed it helps to mitigate the loss of air from your home, such as warm air in winter and cooler air in the summer.

When a damper is closed it also helps to prevent ingress of water into stoves and fireplaces, as well as keeping out any animals and debris.

A fireplace damper should never be closed until the fire in a fireplace has subsided, and any embers and ash have gone stone cold. Fires in fireplaces and stoves still release gas and smoke for a while even after the flames are no longer visible.

A damper for any type of gas fireplace should never be closed.

Fireplace Damper Won’t Open Or Close

Fireplace dampers can be subject to intense heat from fires, and also have to deal with any smoke, soot and ash that pass through them. They also come into contact, and help stop, any moisture or rainwater than makes its way down into the chimney or flue.

As a result, fireplace dampers can become blocked, damaged, corroded, warped or broken over time through use of both the damper and the fireplace.

If the damper is stuck in a particular position then it may need some WD40 and elbow grease, or will require professional cleaning by a chimney sweep. The chimney sweep should also lubricate the damper to ensure it carries on working efficiently.

If the damper won’t open or close using the handle but will move will some manual input, it may be the case that your damper requires a new handle.

If your damper isn’t closing properly then it may be warped or bent, or there may be some debris in the way. Fireplace dampers generally don’t shut with a tight seal and so some small gaps can be expected.

Can You Add A Damper To A Fireplace?

Dampers can be retrospectively added to a fireplace or wood burning stove. Dampers can be installed within throat of the chimney, at the top of the chimney, or within the flue of a stove.

I’ve looked into getting a fireplace damper installed, because as I mentioned earlier, our fireplace doesn’t have a damper.

Having asked my chimney sweep on their last visit to my house, they confirmed that my fireplace and chimney would be suitable to have new damper fitted.

If you’re looking to have a damper installed in your fireplace, speak to few local chimney sweeps to get their views and recommendations. This will also give you an idea of costs so that you can make an informed decision on whether installing a damper in your fireplace would be right choice for you.

Throat dampers and wood stove dampers can be installed if you’re handy with DIY, but top-mounted dampers will require professional installation.

Here’s a video showing how a damper can be installed within a flue:

Can A Fireplace Damper Be Replaced?

Any form of damper can be replaced as necessary, including a chimney throat damper, chimney cap damper or flue damper.

Chimney cap damper replacement will require a professional, but flue or chimney throat dampers and their parts can be replaced if you’re competent with DIY.

How Much Does It Cost To Replace A Damper?

The cost to repair your damper will depend on whether:

  • You have a flue damper, traditional damper or a top-mounted damper.
  • The damper door needs replacing, the damper control handle needs replacing, or the whole unit needs replacing.

According to costestimates.com, expect to pay on average around $60 to replace the door on a traditional damper without professional installation, and between $350 and $400 for a professional installation of the whole unit.

Alternatives To A Fireplace Damper

There are also other options to consider over installing a new damper in your fireplace, including placing a balloon within your chimney when the fireplace isn’t in use.

Chimney Balloon

A chimney balloon works in the same way as a damper and helps to seal the chimney and help prevent the flow of air through it.

Chimney balloons are fairly inexpensive, and can be blown up within your chimney by just using your mouth.

The only downside to a chimney balloon is that they must be removed prior to any fire otherwise the flames and heat will melt and burst the balloon.

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