Do Open Fireplaces Lose Heat?

In Wood Burning Fireplaces by James O'KellyLeave a Comment

Traditional wood burning fireplaces serve the purpose of primarily creating the ambience of having a real open fire in your home.

Open fireplaces can also help to generate small amounts of heat for a room, but when not in use they can also be an unrestricted passageway for air to leave your home.

Rooms with open fireplaces can sometime feel colder than other rooms in a home, and so do fireplaces lose heat?

Open fireplaces can be a significant form of heat loss for a home. A fireplace without a closed damper or form of draft excluder located within the chimney can lead to a cold draft and heat loss during winter months, much like leaving a window permanently open.

We’ve always noticed that our living room can be the coldest room in the house and it’s where our open fireplace is located.

As a result we now use a form of draft excluder to help prevent losing warm air out through our living room fireplace when it’s not in use.

We’ve explained in more detail below why fireplaces can lose heat up the chimney, which types of fireplaces are likely to lose heat, and what you can do to help prevent heat loss from your home.

To help prevent heat loss from your home through your existing open fireplace see the draft excluders we use and recommend that will help you keep the warm air in your home for longer.

Do You Lose Heat Through A Fireplace?

Heat can be lost through open fireplaces that don’t have any form of damper, doors or draft excluder. Warm air from a home can still be lost through other types of fireplace such as gas and wood stoves, but to a much lesser extent.

Fireplaces work by using a draft to help pull waste gases and smoke out of your home during fires.

The draft helps to prevent smoke and other harmful particulates from coming into your home, but a downside of this setup is that there is no restriction to the airflow up a chimney.

This process also makes open fireplaces very inefficient compared to other types of fireplaces, where much of the heat generated by an open fire can be lost up the chimney rather than being used to heat the room.

This unrestricted passage for byproducts from an open fire to leave your home means that warm air also has the ability to leave your home through the fireplace and chimney even when the fireplace isn’t in use.

Chimney From Fireplace
There’s nothing stopping warm air from our home from leaving up the chimney of our living room open fireplace

Heat loss can therefore be a problem with homes that have open fireplaces that are still used for open fires.

Before we used to seal up our living room fireplace with a draft excluder between fires, we noticed that we were losing heat from our home very quickly.

Not only was the living room the coldest place to be in the house (not ideal for a room where you can spend much of your time), but also the house was colder on average.

Our fireplace doesn’t have a damper (more about dampers here) and so we couldn’t seal off the chimney between fires and prevent this heat loss from our home.

We still use our open fireplace for open fires because we enjoy the cozy atmosphere that it creates, and other types of fireplace such wood stoves and gas fireplaced don’t quite provide the same experience that an open fire can.

However, other types of fireplace such as wood stoves can create more ‘sealed environments’ where the airflow through the fireplace and up the chimney can be controlled.

Other members of our family have had stoves installed within their existing fireplaces. Not only has this allowed them to increase the heat output from burning firewood in their homes, it has also created a sealed system where heat loss through the chimney is significantly less.

Register Plate
Heat loss through a chimney can be much less significant when a wood stove is installed and the throat of the chimney is capped off from the room

How Do I Stop My Fireplace From Losing Heat?

Although having an open fireplace can be much like leaving a window consistently open in your home, there are a number of things you can do help prevent heat loss from your home.

To help stop your fireplace from losing heat:

  • Close the damper in your fireplace/chimney between fires (if it has one).
  • Use a draft excluder or chimney balloon to provide a seal within your chimney between fires.
  • Install another type of fireplace inside your existing open fireplace to help provide a more sealed system.

Close the Damper

Many fireplaces will have a metal plate known as a damper located within the throat of the chimney, within the top area of the fireplace.

A damper can be closed between fires to help prevent movement of air up or down the chimney, and therefore help prevent heat loss from a home through an open fireplace.

Pulling the damper handle towards you will typically close the damper, but the damper must be opened before every fire.

For more information about dampers and how to use them see our complete guide to dampers here.

Not all masonry fireplaces will have a damper.

Depending on where you live there can be different regulations about dampers, and so some many open fireplaces (like ours) won’t have a damper. There are solutions other than closing a damper to help prevent heat loss from a home, which we’ve explained below.

Use A Draft Excluder Or Chimney Balloon

As our living room fireplace doesn’t have a damper we instead place a draft excluder within our chimney between fires.

A draft excluder or chimney balloon helps to create a seal and prevent heat loss from a home. However, these aren’t a permanent feature like a damper is and will need to be removed before every fire.

Chimney Draft Excluder
The draft excluder we use

The one we use is known as a Chimney Sheep and it actually works very well. We’ve seen a noticeable difference in the temperature of our living room since using this draft excluder.

See the draft excluder we use and recommend right here.

Draft excluders and chimney balloons come in different sizes and so you’ll need to measure the width and depth of the internal passage of your chimney and choose one accordingly.

We chose a draft excluder that was slightly bigger than the size our chimney so that it could provide a tight fit.

Chimney Draft Excluder
The draft excluder helps to keep heat loss from our home through our open fireplaces

Install Another Type Of Fireplace

In order for wood burning fireplaces to work there needs to be an unrestricted passageway up the chimney for the draft to work and pull smoke and other byproducts from a fire out of your home.

On the other hand, appliances such as wood burning stoves are far more efficient at generating heat for your home and have air vents that allow you to fully control the airflow through the stove and up the chimney.

Many wood stoves allow you to fully close these air vents, creating a completely sealed system where warm air in your home can’t be lost up the chimney.

For more information about installing wood stoves in existing open fireplaces see our other article.

Other types of fireplaces such as gas and electric inserts can also be installed within open fireplaces to help prevent heat loss from a home. See our guide to electric fireplace inserts for more information.

Summary

In order for an open fireplace to work as designed there must be a free passageway for air to leave the fireplace through the chimney.

This helps to remove any smoke or other unwanted byproducts from an open fire from your home, but it also means that heat can be lost up the chimney even when a fireplace isn’t in use.

If your fireplace has a damper ensure to close it between fires, but the damper must be opened again prior to each fire.

For fireplaces that don’t have a damper, products such as a draft excluder or a chimney balloon can be used to prevent movement of air up and down the chimney and therefore help to reduce heat loss. These are more temporary solutions compared to using a damper but can be just as good in terms of helping to stop warm air from leaving through an open fireplace.

The chimney excluder we use and recommend can be found here.

Installing a wood stove inside an existing open fireplace can also help to reduce heat loss because it helps create a seal between the air inside and outside of your home.

Further Reading

Do Fireplaces Actually Heat A Room Or House?

How To Use An Open Fireplace – The Complete Guide

Open Fireplace Tips

Parts Of A Fireplace & Chimney Explained

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