Green Wood Moisture Content

18 Open Fireplace Tips To Help Improve Efficiency And Heat Output

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

1. Only Burn Dry Wood

Many issues associated with poorly burning fireplaces can be the result of using wood that isn’t sufficient for burning, and so it’s important to only burn firewood that is fit for purpose.

This includes making sure that you’re not burning any wood that is:

  • Wet
  • Green
  • Rotten
  • Moldy
  • A form of produced wood such as MDF or plywood
  • Painted or treated

You should also never be burning anything other then dry firewood in your fireplace, such as plastics and other household goods.

To maximize the efficiency and heat output from your fireplace, be sure to only burn wood that is dry enough to be used as firewood.

Dry wood can be identified by a number of features including being brown in color rather than having a greenish tint, the bark can be peeling off, and the ends of the logs can be rough or splitting.

Dry Firewood
A piece of dry firewood ready to burn

Ultimately, the best way to check whether firewood is dry enough to be used is to check its moisture content using a moisture meter.

2. Invest In A Moisture Meter

Many issues associated with poorly burning fires in traditional open fireplaces can be a result of burning wood that is too wet. These problems can include being harder to light, harder to burn and producing more smoke than usual.

To improve the efficiency and heat output from your wood burning fireplace it’s important to invest in a moisture meter.

Moisture Meter
The moisture meter we use. It has helped us to rarely have any problems when burning wood in our home

A moisture meter will be able to accurately read the moisture content of your wood. You’ll want to look out for logs that have a moisture content of 20% or lower, as this wood will catch alight and burn much better than wood with a moisture content higher than this number.

Wood gets progressively harder to burn on a fireplace as the moisture content rises above 20%. Depending on the time of year the wood is cut, the moisture content of the wood can be upwards of 30% all the way to 100%, meaning that the wood needs to be dried out before it can be used as firewood.

Green Wood Moisture Content
Wet (green) wood is too high in moisture content

This process of drying out the wood is known as seasoning, where the wood needs to be left outside under shelter for up to two years.

Wood can also be kiln dried to vastly increase the drying process, but expect to pay more for kiln dried wood. When buying wood you should look out for wood that has either been ‘well-seasoned’ or ‘kiln dried’ as it will typically denote wood that is ready to be used in your open fireplace.

Not all wood will be dry enough to burn efficiency though, and so a moisture meter really helps to ensure that the only wood you’re burning is wood that is dry enough to burn effectively.

We’ve explained how use a moisture meter to measure the moisture content of wood in another article here.

A moisture meter is an essential tool for any fireplace.

If you don’t already have a moisture meter you can check out our favorite moisture meter here.

If you’re in the UK you can find the moisture meter we use over on Amazon here.

3. Dry Your Own Wood Properly

If you’re seasoning your own wood then you’ll need to ensure that you’re providing the best atmosphere and platform for your wood to dry.

Depending on the time of year the wood was cut and whether you’re drying out softwood or hardwood logs, then the time it takes for the wood to dry out can take anywhere from 6 months to 2 years.

It’s therefore important to ensure that your seasoning arrangement is setup correctly to allow the wood to dry out as fast as possible, and without causing it to rot.

Wet wood should be stacked on a dry platform to allow water to runoff into the adjacent ground, and to also prevent moisture from the ground from seeping back into the wood. The logs should also be placed under an overhang to help protect them from the majority of the rainfall.

Most importantly is that the stack is open on one side to allow the wind and sun to dry out the wood. The logs should not be placed under a cover such as a piece of tarpaulin, as this can cause the wood to rot rather than dry out.

We season our own wood, and our arrangement for drying out the wood follows the above principles.

How we season our own firewood

You can read more about how we season our own wood here.

All of the wood we season ourselves we check with a moisture meter to ensure that it’s dry enough to use in our fireplace.

4. Bring In The Wood Before Each Fire

If you’re burning wood in your open fireplace taken straight from the outside, or from a colder place in your home such as a garage, then it may be affecting how efficiently your fire is burning.

Cold wood can be harder to burn, as so we like to bring in enough wood the day before each fire to ensure that the wood we’re burning is at room temperature.

Wood Storage
Bring wood indoors before having a fire so that you’re not burning cold wood

Burning room temperature wood can help to maintain a fire as it can take extra energy from the fire to heat up colder logs.

5. Have Your Chimney Swept Periodically

It’s recommended to have your chimney cleaned at least once per year to ensure that it can carry waste gases and smoke out of your home without any issues.

It’s best to have it swept before your burning season, but your chimney may require cleaning more often than annually if you’re burning wood regularly in your home.

A dirty or blocked chimney can reduce the effectiveness of the draft, as well as preventing gases and smoke from leaving your home properly.

The main cause of your chimney becoming dirty and blocked is creosote (tar), which can be released by wood in different quantities depending on how well it’s burning. Wood that is burning well will release little or no creosote, but wood that is burning inefficiently can produce smoke and creosote in increased amounts.

As poorly burning wood can release creosote in higher quantities, it’s important to ensure that the wood is dry enough, there is enough air supply to the fire and there is sufficient draw on the fireplace from the chimney.

Softwoods tend to have higher sap content and so burning hardwoods over softwoods can help to reduce the building up of soot within your chimney.

6. Ensure That The Damper Is Fully Open Before Each Fire

Many traditional open fireplaces have dampers installed within the throat of the chimney, which help to prevent the loss of air from your home when the fireplace isn’t being used.

Dampers should always be fully opened before every fire in your fireplace, otherwise smoke and waste gases will spill out into your home rather than leaving up the chimney.

A fully open damper before starting a fire helps to ensure that there’s the maximum amount of draw on the fireplace from the chimney, and can help the fire to get going more quickly when its lit.

Many dampers can be opened and closed using a handle that sticks down within the inside top of the fireplaces. Other dampers may have screw handles, while top-mounted dampers will have a chain that hangs down into the fireplace that you’ll need to pull down to open.

For our complete guide to fireplace dampers check out one of our other articles here.

7. Prime The Chimney To Help The Fire Get Going

Warming up the air inside the chimney (known as priming) can help to ensure that there is sufficient draft before starting a fire.

A strong draft will help pull waste smoke and gases out of the fireplace more quickly, and in turn feed the fire with more oxygen from the room. Warming the chimney prior to a fire can therefore help a fire to get going more quickly, and reduce the chance for any issues to occur such as the fire going out or smoke being produced.

You can warm the chimney using a heat source such as a lit piece of newspaper.

To prime our chimney we simply take a rolled piece of newspaper, light it at one end and hold it inside the chimney opening under the top of the fireplace for a short period of time.

Warm Chimney Priming
Holding a heat source below your chimney can warm up the air inside it and start the draft on the fireplace before having a fire

Smoke from the newspaper being pulled up the chimney is a sign that the draft is working well enough to start a fire.

Prime Chimney Smoke
Smoke being pulled up the chimney is a good sign

You can also use another heat source to warm up the chimney, such as a hairdryer or lighting a couple of firelighters in the fireplace on their own and leaving them to burn through.

8. Build The Fire Correctly

Building the right fire in your traditional open fireplace will help the fire to get going as quickly as possible and reduce the potential for any issues to occur.

The traditional way to build a fire in an open fireplace is to build the fire up with the fire starter at the bottom and placing the logs at the top.

Placing crunched up pieces of newspaper at the base of the fireplace will help to spread the fire more quickly to the initial bits of kindling. The newspaper shouldn’t be over tightened otherwise you will cut off the air supply. Likewise, the crunched up pieces of newspaper shouldn’t be too tightly packed inside any fireplace grate, to aid with airflow.

The newspaper can also be placed under a fireplace grate to help prevent movement once the newspaper has burnt through.

Fireplace Newspaper
Using newspaper helps to transfer the flames to the kindling

The kindling should be small pieces of dry softwood. Softwoods can catch alight more quickly than hardwoods and, which is important for helping the fire to get going as quickly as possible after lighting. The kindling should be small so that the flames can catch hold of them as quickly as possible. Larger pieces of wood are harder to light and require higher temperatures, and so burning large logs too early into a fire is an easy way to cause the fire to go out.

Any kindling should be laid on top of the newspaper in a cross-cross pattern to allow for air to flow between the bits of wood.

Fireplace Kindling
Kindling should be added on top of the newspaper

A couple of smaller sized logs can then be added on top of the kindling to complete building the fire.

Fireplace Logs
Logs can be placed on top of the kindling to finish building the fire

For more information we’ve explained how to build a traditional fire in a fireplace in much more detail here.

9. Try The Top-Down Fire Method

To help increase the initial efficiency and heat output of a fire in your open fireplace, you can try building a fire using the top-down method.

The top-down fire method uses the same materials as the traditionally built fire, but they are added to the fireplace in reverse order.

To build a fire using the top-down method, place a layer of your largest sized logs a the base of your fireplace or grate, and then lay another row of smaller sized logs on top.

Fireplace Top Down Fire
Add your largest logs at the base of the fire, ideally with the ends of the logs facing towards you
Fireplace Top Down Fire
Add smaller sized logs on top at a perpendicular angle

Kindling can then be added on top of the logs and then your preferred fire starter such as newspaper placed at the top of the fire.

Fireplace Top Down Fire
Add kindling on top of the logs in a crisscross arrangement
Fireplace Top Down Fire

The main benefits of using the top-down fire method are that it can last longer before further logs need to be added to the fire, and can provide a cleaner burn with less smoke straight from the start because the fire isn’t being smothered by logs on top.

For our complete guide to building and lighting a fire in an open fireplace using the top-down method click here.

10. Get The Fire Going As Quickly As Possible

Building either type of fire in your open fireplace similar to what has been mentioned above will help when it comes to getting the fire going as quickly as possible.

A slow burning fire that is taking longer to get going after being lit can have more of a chance of going out. It’s therefore important to light the fire at various points to increase the success rate.

We like to use long matches to help us reach and light a number of different locations across the built fire. This helps the fire to spread more quickly to the wood, and the long matches help when it comes to safety while other parts of the fire are starting to burn.

Fireplace Long Matches

11. Sustain And Increase The Fire By Progressively Using Larger Sized Logs

If you’ve built a fire in your fireplace using the traditional method then larger sized logs can be harder to catch alight and harder to burn when used too early into a fire.

You should therefore plan to add progressively larger sized logs as the fire progresses. Once a bed of hot coals has been established within your fireplace it will be easier for the largest logs to catch alight and burn.

12. Don’t Burn Logs Too Tightly Packed Together

Fire needs oxygen to survive and so packing logs together too closely on a fire can prevent the air from circulating properly, leading to inefficient burning and less heat output.

Likewise, burning logs that are too far apart from each other can also lead to inefficient burning because the heat can’t be transferred from one piece of wood to another as effectively.

The best formation for burning wood in your open fireplace is to prop them up against each other so that the heat and flames can transfer between them for efficient burning, while also allowing air to circulate around the logs.

A poker is an essential fireplace tool that can be used to position the logs once they’re added to the fire, or to rearrange them once they’ve burnt through.

13. Use Hardwood Logs For Increased Heat Output & Duration

Hardwood logs, such as Oak or Ash, are typically denser than softwood logs, such as Pine, meaning that more heat can be produced over a longer period of time because they can burn at a slower pace.

A downside of burning hardwoods is that they usually take longer to dry out (season) compared to softwoods, and so this can be reflected within the price when buying in your firewood.

We always burn hardwoods logs in our open fireplace to ensure that we’re getting the most amount of heat from every log, while also increasing the time needed between adding more wood to the fire.

Kiln Dried Hardwood Firewood Bag
We always burn hardwood logs for increased efficiency and heat output

14. Maintain A Hot And Efficient Fire

Burning a hot fire in your open fireplace will not only produce more heat, but will help to minimize any smoke or creosote being generated by the fire.

A hot and well-burning small fire is far more efficient than a large smoldering one. Allowing for good airflow to the fire and burning dry logs that have 20% or less moisture content, along with having a clean chimney, will help to promote a hot and efficient fire.

15. Add A Couple Of Logs At A Time

Adding more than one log at a time to a fire can help to promote a better burning fire.

Logs placed on a fireplace that are rested on each other can help with heat transfer between the logs, and allow for air to circulate around the logs for better burning efficiency.

16. Keep Any Glass Doors On The Fireplace Open During A Fire

Research has shown that keeping the doors closed during a fire in your open fireplace doesn’t provide as much heat to the room as leaving them open.

You should therefore try to refrain from closing any glass doors on your fireplace during a fire.

For more information you can read our complete article on glass fireplace doors here.

17. Open Any Air Vents In The Room

Many open fireplaces (like ours) come with an external air vent located within the room to help with the supply of fresh air to the fire.

Fireplace Vent
We open our external air vent before each fire

Some fireplaces can pull air from the rest of the house to supply air to a fire, and so an external air vent can help to mitigate the issue of heat loss from a home during a fire.

If you’re finding that your fireplace is smoldering or smoking even with a vent open then try cracking open a window slightly within the room to aid with air supply.

18. Don’t Close The Damper Too Early After A Fire

If your open fireplace has a damper, be sure not to close it too soon after a fire to help prevent any waste gases or smoke from coming into your home.

Hot coals can continue to smolder within the ashes for many hours even after the flames have subsided, and can therefore continue to produce gases.

Closing the damper too soon after a fire can cause any gases and smoke to come into the room rather than leaving your home up the chimney.

Further Reading

How Fireplaces Work

What Moisture Content Wood Should Be And How To Check

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