My parents have recently installed wood burners in their homes, and so asked me for any advice on how to get more heat from wood burning stoves.
Wood burning stoves help you to get more heat out of burning wood than a traditional open fireplace, where much of the heat can be lost up the chimney rather then heating your home.
How much more heat you can actually get out of a stove can depend on a number of factors. The main factors can include the type wood that you’re burning and it’s moisture content, how well the air supply to the fire is being controlled, and how well you’re maintaining the fire.
As getting more heat output from burning wood was the main reason my family members decided to wood stoves, I’ve researched this topic quite thoroughly.
I’ve therefore put together the 10 best ways to get more heat from your wood burning stove, that will hopefully help you provide more warmth to your home.
How To Get More Heat From Wood Burning Stoves
Here’s the complete checklist for how to get the maximum heat from wood burners:
– Start the fire by using softwoods to quickly get the fire going.
– Use hardwoods after the fire has got going to produce even more heat than softwoods, and over a longer period of time per piece.
– Ensure that all wood burnt is dry and not high in moisture content.
– Maintain the flames by periodically adding a few pieces of wood, rather than waiting for the flames to subside or adding large volumes of wood at once.
– Once the fire has got going keep the stove door closed at all times, and try to keep the time the door is open to a minimum when adding wood.
– Use the air vents to correctly control the airflow to the fire.
– Have your flue cleaned periodically to ensure efficient and maximum draft.
– Clean and maintain your stove as required to ensure no blockages to air vents preventing sufficient airflow for the fire.
– Ensure adequate ventilation within the room to feed the fire oxygen.
Getting the most heat from a wood burner can be a bit of a skill. With so many factors determining how much heat you get out of burning wood, it’s important to understand how each factor contributes to heat output and what you can do to improve it.
Read on to find out more detail on how to get more heat from wood burning stoves.
Burn Well Seasoned Wood
To make the most of your wood burning stove you’ll need to being using the correct dryness of firewood. The terms that define wood that is acceptable for burning in a wood stove are well seasoned and kiln dried, and you’ll want to look out for these terms if you’re buying the wood.
Well seasoned wood is logs that have been left to dry over a prolonged period of time to allow moisture within the wood to evaporate to acceptable levels. In general, softwoods should be left for at least six months and hardwoods left to dry for at least a year before being used as firewood, but will depend on the type of wood.
Kiln drying wood significantly increases the drying time of freshly cut wood, but can be reflected in the price of the wood.
Only well seasoned or kiln dried wood with suffcienltly low moisture content should be used in your stove. Higher moisture content wood requires more energy to burn off the excess moisture, therefore reducing the overall heat output.
For best results, try to only use wood with a moisture content of 20% or less. Wood with a higher moisture content will be harder to burn and be much less efficient at giving off heat in your stove.
The main benefits of using well seasoned wood over high moisture content wood include:
- Easier to light
- Stronger flames
- The fire will keep going for longer
- More heat will be produced
- Less smoke will be released
In comparison, wood with higher than adequate moisture content will be harder to light, burn less easily, produce much more smoke and ultimately give off less heat.
Signs that you are using wood that is too wet include being hard to light, hard to maintain, significant amounts of smoke, hissing noises from the fire or noticing that the glass on your stove door is turning black. A lot of smoke is a sign that the fire is releasing gases that weren’t fully burnt.
You can use a moisture meter to read the moisture content of your wood, or by looking out for signs that your wood is dry and ready to use:
- The wood has split ends
- Is darker in color
- Sounds hollow when banged together
- The bark is peeling away
For more reassurance that the wood you’re buying is dry, you can also use kiln dried logs which have been artificially dried in a kiln to vastly speed up the seasoning process. Kiln dried logs can therefore be more expensive than seasoned wood but you can feel more comfortable that the wood is more likely to have reached the 20% moisture recommended moisture content threshold.
If cutting and drying the wood yourself, be sure to cut the wood in winter when moisture content is at its lowest. This wood will requires less time to dry than wood cut in spring or summer when moisture content will be higher, and it will have all of the warmer months to be able to dry out.
Leave any cut softwood to dry for at least six months, or 12 months for hardwoods, in store it in an area with base, sheltered from the rain but open to allow the air and wind to improve drying times
Use Hardwoods Over Softwoods
Burning hardwood logs such as Oak over softwood logs such as Pine will produce a higher overall heat output over the length of your fire.
As softwoods light and burn much more easily than hardwoods, they’re great to use at the start of the fire as kindling and for the first couple of logs. Softwood help to get the fire going quickly and to increase the temperature within the stove, but burn much more quickly than hardwoods.
Hardwoods burn hotter and for longer than softwoods, and can replace softwoods as the fuel once the fire has really got going. Hardwoods are denser than softwoods and create hotter coals that provide the heat for longer periods of time.
Hardwoods are therefore great if you’re looking to maximum the heat output from your stove over the longest time possible, and should be used if you’re looking to keep your house warm overnight.
The downside of burning hardwoods over softwoods is the added cost. Hardwood trees generally take longer to grow, and the chopped wood takes longer to dry out, meaning that they are usually more expensive to buy.
Maintain The Fire
A key way to increase the total heat generated by your wood burning stove is to keep the fire going strongly at all times.
Adding a few logs at a time as necessary will help the fire maintain its momentum. This is instead of loading as much wood as you can into the stove at frequent intervals, or waiting for it to burn down fully before adding any more logs to the fire.
You’ll want to aim for a bed of hot wood with one or two logs burning on top and any one time. A layer of red-hot embers will produce a substantial amount of heat.
Not adding enough wood to your stove will prevent the stove from reaching optimum operating temperatures, and can impede the secondary burn effect within a stove (which provides even more heat).
Adding too much wood can smother the fire, and can cause ‘overfiring’ of your stove which could potentially cause permanent damage to it over time.
Check your manufacturer’s recommendations for the best ways to maintain the fire in your particular model of stove.
Use Room Temperature Wood
Using wood that is too cold can impact the momentum of the fire in your stove.
This is particularly problematic if you’re adding wood to the fire that has come straight from outside or from a colder place in your home, such as a garage.
Cold pieces of wood will take longer to reach combustible temperatures, and will therefore impact how much heat your wood burning stove is producing.
To give wood sufficient time to reach room temperatures and to ensure maximum heat from our wood burning stoves, we now always make sure to bring in the required amount of wood at least a day before using it in a fire.
Keep The Door Closed
The vast majority of wood burning stoves are designed to be used with the door closed for maximum efficiency. Leaving the door open compromises how well the stove will be able to produce heat.
With the door closed, the airflow can be regulated by the air vents. These air vents should be used to control the airflow into the stove, and not by using the door. An open door will allow for increased airflow, leading to the wood burning more quickly and more heat being lost up the flue.
Feeding small amounts of wood too often to the fire will continuously disrupt the airflow and the operating temperatures of the wood burner, and so be sure to only add one or two larger logs when necessary to keep door opening frequency and times to a minimum.
By keeping the flow of air regulated, the stove can reach temperatures hot enough to provide secondary burn, whereby any un-burnt gases are combusted to produce even more heat.
Therefore, leaving the door closed on your wood burning stove will help it reach maximum efficiency by enabling the air flow to be regulated by the air vents only, and allowing for higher temperatures and secondary combustion of gases to be reached.
Control the Airflow
A wood burning stove can multiple sets of air vents that can be manually opened or closed in order to control the airflow to the fire.
By adjusting how open particular sets of vents are you can help to control how much oxygen is getting to the fire, and therefore how quickly the wood will burn and how much heat is being produced by the stove.
You should always keep the air vents open when lighting the fire to maximize airflow and to get the fire going quickly. This is the only time at which the stove door should also be left open to increase airflow.
Primary (bottom) vents can usually be closed when the fire has got going. Secondary (top) vents help control the feed oxygen to the fire and can prevent your stove glass from turning black. Tertiary (back) vents it can help your stove output more heat through secondary burn of waste gases.
With the vents open too wide you can burn through your wood too quickly and introduce too much cold air into the fire.
Air vents that are too far closed can smother the fire and lead to sub-optimal operating temperatures.
Finding the best use of your stove’s air vents will help you ensure a clean burn of wood in your stove and to maximize the amount of heat from your fire.
Each wood burning stove is different and so it will take time to understand and master the use the air vents to control the fire! Be sure to check your manual for best operating procedures for the vents on your particular model of stove.
Regulate the Damper
Your damper (should you have one) will generally be located just above stove inside the flue. The damper can be opened or closed to help regulate the draw on the wood burning stove and the airflow out of the stove.
You’ll need to have the damper open when the stove is in use to release any smoke and gases produced from the fire out of your home. Don’t completely close off the damper at any time during use of the stove, or for a prolonged period of time after use, otherwise smoke or harmful gases can instead be pushed out into your home.
The damper should be fully open you starting the fire in the stove, and usually left open for at least 30 minutes after lighting to get the fire going.
The damper can then be adjusted as part of the stove controls to try and increase the heat generated by the fire, and in turn the heat emitted by the stove.
The amount to close your damper by will depend on your model of stove and the draw of your flue. As every stove and situation is different, it’s therefore a case of trial and error for each and every wood burning stove to find the best way to use the damper to maximize the heat output.
If you don’t have a damper then you may want to think about getting one installed. Too much draw can cause the heat to be sucked away from the stoves too quickly, leading to less heat being radiated into your home.
Clean & Maintain the Stove
It’s important to periodically maintain your wood burning stove to ensure that all air vents are cleaned of any excess ash.
You won’t want to continuously clean all the ash out of your stove, as wood burns better when laid on an existing bed of ash. Too much ash can become problematic though, so be sure to keep the level of ash to a reasonable amount (a couple of centimeters is great. When cleaning, keep any ashes or bits of burnt wood away from the air vents to help prevent problems with airflow when next using the stove.
Also make sure that a tight seal is provided by the stove door, to ensure that the air vents are the only source of air flow into the stove.
If your wood burning stove is brand new, don’t expect it to work at maximum efficiency right away. You’ll need to use it a couple of time to break it in.
Keep Your Flue Clean
Have your flue cleaned in line with recommended guidelines. They should be cleaned yearly, ideally before the winter season when the wood burning stove is most likely to be used. Regular use of a stove may require the flue to be swept every season.
A dirty flue can reduce the efficiency of the draw on your stove (the suction of air up the flue) and therefore affect the efficiency of the fire. A blocked or partially blocked flue will affect its overall diameter, which in turn will reduce the potential draft.
Burning wood also releases creosote, a highly flammable substance that can line the walls of your flue, and over time buildup to become a potential fire risk hazard.
The amount of creosote released by the fire can depend on how well the fire burns the wood. If the there is a lack of airflow to the fire, or the wood being burnt has a high moisture content, more smoke can be produced by the fire leading to higher amounts of creosote being released.
Ensure Adequate Room Ventilation
Sufficient ventilation within the room is important to ensure that plenty of oxygen gets to the fire and helps improve the draft up the flue.
We always open any doors and vents within the room, and crack open a window a few centimeters if it looks like the fire needs more fresh air.
How To Get More Heat From Wood Burning Stoves
Probably the most important factor in maximizing the heat from your wood burning stove (as we’ve found) is choosing the right type of firewood. The wood must be sufficiently low in moisture content to burn properly.
High moisture content wood is harder to light, harder to burn, produces more smoke and makes everything dirty much more quickly. Choosing the right firewood is therefore key to a successful fire and to ensuring that your stove is producing as much heat as it was designed. I would say that the amount of heat provided by your stove will only ever be as good as the wood that you’re using.
Once you’re using the best firewood possible, you can learn to control the air vents and learn how much wood is best for your stove at any one time. You should always keep on top of cleaning and maintaining your wood burning stove, keep the stove door open to a minimum and ensure adequate ventilation in the room.