Are Open Fireplaces Efficient?

Traditional open fireplaces can be found in many homes both new and old, but open fireplaces have never been known for their efficiency when it comes to generating heat.

Open fireplaces allow you to have a real fire in your home without it located behind a sealed glass door as you would find with wood burning stoves, but how efficient actually are traditional open fireplaces?

Open fireplaces are not a very efficient source of heat for a home and can be as low as 10% efficient. Much of the heat generated by an open fire can be lost up the chimney instead of being used to heat a room. The draft can also pull heat out of the room and potentially make a house colder.

Wood burning fireplaces can be an inefficient way to heat a home but can provide the most realistic fireplace experience out of all the different types of fireplaces, with a full experience of a fire sounds and smells.

We’ve explained in more detail below:

• What the typical efficiency is of open fireplaces.
• Why traditional masonry fireplaces can be so inefficient.
• What you should be using your wood burning fireplace for.
• What you can do to help make open fireplaces more efficient.
• The options for installing more efficient forms of fireplace.

What Is The Efficiency Of An Open Fireplace?

Traditional open fireplace can be as little as under 10% efficient, where over 90% of the heat generated by an open fireplace fire is lost up the chimney rather than being used to heat a room.

Regarding efficiency for wood burning fireplaces, the Environmental Agency (EPA) explains that:

‘Most traditional open fireplaces lose over 90 percent of the fire’s heat out the chimney, and much of the heated air in the room goes with it.‘

EPA

You therefore shouldn’t expect to be able to efficiency use an open fireplace as a way to heat your home.

We typically only use our own traditional open fireplace for enjoyment purposes.

We love the feel of our living room looking all cozy with a roaring fire throughout the colder months of the year. We know that we won’t be able to get much heat out of these open fires and so we simply enjoy the view, sounds and smells of the fires without worrying about trying to get more heat out of them.

Why Traditional Open Fireplaces Can Be So Inefficient

Traditional open fireplaces work by using the draft created by hot air rising up the chimney to be able to pull waste gases and smoke out of your home.

Unfortunately, this also means that much of the heat generated by an open fireplace fire is also lost up the chimney.

Some of the heat is radiated out into the room but this can’t as easily be felt if you’re sat across the room. We have to sit near our open fireplace to feel any real heat.

As air from an open fireplace fire can move up a chimney so quickly there isn’t enough time for processes such as secondary combustion, commonly found in wood stoves, to occur.

Another downside of the airflow up a chimney is that it can also pull warm air out of your house and potentially leave you with an even colder home than you did before.

The EPA explains that:

‘Fireplace drafts can pull the warm air up the chimney, causing other rooms to be cooler.’

Environmental Protection Agency

For more information we have a complete guide on how an open fireplaces work, but in summary the diagram below shows the air flow through an open fireplace and chimney.

What You Should Be Using Your Open Fireplace For

Traditional open fireplaces can be a very inefficient source of heat for your home.

You therefore shouldn’t expect to use your open fireplace as a sole way to heat a room in your home, or even your whole house.

Open fireplaces should be enjoyed for what they’re best at, and that’s providing a real open fire in your home for you to enjoy looking at and listening to.

The EPA explains that:

‘Most fireplaces, whether masonry or low mass, are not used as a primary source of heat; their function is primarily for ambiance’.

Environmental Protection Agency

We really only use our open fireplace for ambience purposes but use our electric fireplace as a heat source as it’s far more efficient.

How Can I Use My Fireplace Efficiently?

As traditional open fireplaces were never designed with efficiency in mind, there will only be so much you can do to improve the heating efficiency of your open fireplace.

To use your open fireplace efficiency always only burn properly seasoned or kiln dried firewood, and using hardwood logs will help to provide the most amount of heat from each piece of wood. Also ensure to have your chimney swept at least annually so that the draft is working as efficiently as possible.

In summary:

• Burn only kiln dried or properly seasoned firewood that has around 20% or less moisture content. You can use a moisture meter to check the moisture level of your firewood.
• Keep your chimney clean and clear of any creosote by having it swept at least every year, and ideally before your main burning season.

These are the two main things that you’ll need to focus on in order to use your traditional open fireplace as efficiently as possible.

However, there are also a number of other things you can do to further improve the efficiency of your open fireplace, and we have a complete guide of all the tips and tricks you can do to maximize the efficiency and heat output from your fireplace here.

More Efficient Fireplace Options

Although traditional open fireplaces can give you the best real fireplace experience, they aren’t the best form of fireplace to use for heating purposes.

If you’re looking to get more heat out of your fireplace then you can consider installing other types of fireplace inside your open fireplace.

The main types of fireplace you can install within an open fireplace to improve efficiency include:

• Gas inserts
• Electric inserts
• Wood burning stoves
• Multi fuel stoves
• Wood burning inserts

Wood Stoves

We’ve been considering installing a form of stove in our own living room fireplace but we’re yet to decide which one.

A downside of installing an insert or stove into your existing open fireplace is that it removes the ability to have ‘open’ fires. However, the potential increase of heat output from your fires can more than make up for this loss.

We have two open fireplaces in our home and even if we installed a wood stove in one of them we would still be able to enjoy open fires in the other if we wanted.

A number of members of our family have already had stoves installed within their existing open fireplaces:

We have another article here that explains what you need to know about installing a wood stove in an existing fireplace.

The heat output from our wood burning and multi fuel stoves far exceeds the warmth that we can achieve from our traditional open fireplace. This is because stoves are designed with efficiency in mind, where both the amount of heat extracted is maximized and emissions are minimized.

While open fireplaces can typically have efficiencies of 10% or lower, stoves typically have much higher efficiency ratings.

For example, our stoves have official efficiency ratings of over 70% each, meaning that they’re very good at converting the burning firewood into useable heat.

Electric Fireplaces

Electric fireplaces are another option for increasing the efficiency of your existing open fireplace.

Electric fireplaces inserts can be installed within the opening of  your traditional fireplace, or you can opt for what we do and simply place an electric stove in your fireplace during the months when the open fireplace isn’t in use.

An electric fireplace doesn’t have real flames and so you can enjoy the ambience of a fire in your home even through the warmer months.

For more information about electric fireplaces see our complete buying guides for each type of electric fireplace.

Summary

Traditional open fireplaces aren’t very efficient sources of heat for a home.

The Environmental Protection Agency states that wood burning fireplaces can be as little as 10% efficient, with most of the heat produced by an open fire being lost up the chimney.

An open fireplace should therefore be primarily used as a way to enjoy the ambience of a real fire on your home, and the ability for it to be able to efficiently heat a room in your home should be an afterthought.

If you’re looking to maximise the amount of heat from your open fireplace see our list of the best tips and tricks for using your open fireplace to maximize heat output and efficiency.

Other types of fireplaces can also be installed to help vastly increase both the efficiency and heat output in your home from burning firewood, and these include wood burning stoves and multi fuel stoves. Electric fireplace inserts can also be installed into an existing open fireplace, but at the loss of the ability to have a real fire.

Further Reading

How To Use An Open Fireplace (The Complete Guide)

Parts Of A Fireplace Explained

Electric Fireplace Buying Guide

What To Look For When Buying A Wood Stove