How to season firewood
If you’re lucky enough to have your own supply of firewood, your heating costs could be dramatically lower over the year. However, it is important that you don’t immediately burn those freshly cut logs – they need to be dried before you burn them.
What is seasoning wood?
Seasoning firewood is waiting for your wood to lose moisture. The cells within your logs contain moisture which makes them a lot harder to burn and a lot less efficient. By seasoning your firewood, you are letting the moisture naturally evaporate and reducing it to 20% or less.
Wood that is not seasoned is often called unseasoned, wet, or green wood. Wood that is seasoned is often called dry, seasoned, or Ready to Burn wood.
Freshly felled trees and the logs you split from these trees will have a high moisture content – often times up to 50%. You should only burn wood fuel that has a moisture content of 20% or less. This ensures that you are getting more heat per log, producing much less soot, reducing your risk of a chimney fire, and emitting far less pollution.
How to season wood
The three key things your wood will need to season are time, air, and sunlight. Despite these three factors doing the long-term work, getting your freshly felled logs ready to be seasoned requires a bit of legwork.
Firstly, you are going to need to find – or build – a log store that can hold all your wood. There are a range of log stores available on the market that come pre-built, but you can also build your own, making sure it is:
- Raised from the ground, allowing air to circulate
- Sheltered from the elements, protecting it from the rain or snow
- Able to get plenty of sun throughout the year
The next step is to split your logs, usually into small enough pieces that they can be put into your stove straight after they have dried. This increases the surface area and reduces the thickness of your logs, speeding up the drying process significantly.
Now the hard work is out of the way, you can start to see your log store taking shape. Start to stack your logs atop one another, not wedging them too tightly together – air circulation is the primary way your logs will lose their moisture. Make sure you also don’t create multiple layers of logs; there should not be logs behind other logs as this will reduce the airflow, lengthening the drying time. For safety, it’s best to stack a couple of logs then continue horizontally – you don’t want a tall, unsupported vertical stack potentially falling down onto you.
Once your log store is looking complete, you can sit back and relax – the hard work is done. All you’ll need to do is wait. Periodically checking in on your log store and measuring the moisture content of multiple logs will let you check the progress and see how the seasoning process is going.
During periods where rain or snow is especially heavy, it may be good to cover your store with some tarpaulin to prevent them from getting too wet. A bit of surface moisture won’t make a difference to the drying process, but long periods of heavy rain can cause issues and delays.
Benefits of dry wood
Dry wood is perfect for burning in your stove – there is a reason that it is against the law in England to sell firewood that has a moisture content of 20% or more.
Dry wood produces:
- More heat per log
- Less emissions as it burns
- Much less black soot on your stove glass
- Significantly reduced creosote in your chimney
Using dry wood not only will keep you warmer for longer, but it also means you have to clean your stove much less frequently. Seasoning your firewood pays dividends once you put in the hard work, keeping your home warm and safe.
Dangers of wet wood
Wet wood is not meant to be burned in your stove. All stove manufacturers strongly advise against using wood that has not been dried as it produces:
- Much less heat per log
- Significantly increased emissions
- High amounts of soot on your stove glass
- Large deposits of flammable creosote in your chimney
When burning wet wood, you will not only get much less heat as your fire has to waste energy on burning away excess moisture, but you also risk a chimney fire. Wet wood often isn’t able to burn fully in your stove, resulting in incomplete combustion. This creates a huge increase in soot, carbon monoxide, and other harmful pollutants.
When to season wood
Generally, late spring is the best time of the year to season your wood. This will allow you to avoid the rainier weather as you split your logs, prevent too much rain from hitting your logs as they are first drying, and allow a full summer of sun to hit them almost immediately. Hardwood generally takes between eighteen months and two years to sufficiently dry, so your logs may also be usable as the weather begins to cool down, depending on a few factors.
However, it isn’t always the case that you will be able to source your own wood and split them in time to align with this date. The second-best time to season your firewood is as soon as you can! Leaving freshly felled logs out on the ground increases the chance of mould growing, the wood rotting, and insects causing irreparable damage.
The HETAS Advice Hub has a range of tips and advice to ensure you can continue to burn safely and responsibly.
