How Wet Firewood Could Be Costing You Money

There’s nothing quite like getting the stove going when the temperature drops here in the Scottish Borders. A good fire should light readily, burn steadily and give off the warmth you expect, but when that does not happen, it is easy to assume there is a problem with the stove itself. If you are getting through logs more quickly than usual, struggling to establish a consistent flame or finding that the glass blackens soon after lighting, the problem may actually be the firewood you are using.

The moisture content of firewood has a significant effect on how well it burns. HETAS recommends using wood with a moisture content of 20% or less because properly dried firewood is easier to light, produces more useful heat and creates less smoke and tar than wet logs. The difference is not simply one of convenience. It can affect how much fuel you use, the condition of your stove and chimney, and ultimately how much it costs to keep your home warm.

At Pearsons of Duns, we have been supplying fuel since 1920. More than a century of experience has shown us that choosing the right fuel is every bit as important as choosing the right appliance, particularly in rural and older properties across the Scottish Borders where a stove may provide valuable additional warmth throughout the colder months.

Freshly cut wood naturally contains a high proportion of water. Before it is ready to be used as firewood, much of that moisture has to be removed through careful seasoning or kiln drying. Although a log can feel dry on the outside, its centre may still hold considerably more moisture, which is why appearance and touch alone are not always reliable indicators of whether wood is ready to burn.

When wet firewood is placed on a stove, part of the heat generated has to be used to evaporate the water held inside the log before the wood can burn effectively. That energy is therefore not being used to warm the room. The result can be a cooler, less consistent fire that needs more attention and more fuel to maintain the temperature you want.

Dry firewood behaves very differently. It lights more easily, reaches an effective burning temperature more quickly and produces a steadier flame, allowing a greater proportion of the energy in the wood to become useful heat. During a Scottish Borders winter, when a wood-burning stove may be used regularly for several months, that improvement in performance can make a noticeable difference to both comfort and fuel use.

Could wet firewood be costing you money?

The price of a bag, net or load of firewood is only part of its true cost. If the logs contain a high level of moisture, some of what you are paying for is water, and some of the energy released by the fire will then be spent removing that water. You may need to add logs more often or burn a larger quantity to achieve the same level of warmth, so a cheaper supply of poorly seasoned firewood can prove to be a false economy.

By comparison, good-quality kiln-dried firewood offers more reliable performance because it is already dry enough to burn efficiently. This does not mean every stove will use exactly the same amount of wood, as appliance efficiency, room size, insulation, airflow and the way the stove is operated all play a part. However, starting with fuel at the correct moisture level gives your stove the best opportunity to deliver the heat and burn time it was designed to provide.

There may also be longer-term costs to consider. Wet wood tends to burn at a lower temperature and produce more smoke, soot and tar, which can contribute to deposits in the stove, flue and chimney. Dry firewood does not replace the need for regular chimney sweeping and stove maintenance, but using suitable fuel can help your appliance burn more cleanly and reduce avoidable build-up.

Signs your firewood may be too wet

Your fire will often give you an early indication that the moisture content of your logs is too high. One sign on its own does not necessarily prove that the fuel is wet, because airflow, lighting technique and the condition of the appliance can also affect performance, but several of the following symptoms together are a good reason to check your firewood:

• the wood hisses, spits or bubbles as it heats;
• the fire is difficult to establish, even with suitable kindling;
• the logs smoulder rather than producing a strong, steady flame;
• the fire produces excessive smoke;
• the stove glass blackens quickly; or
• you have to add logs frequently without getting the heat you expect.

If these problems persist, check that the air controls are being used in line with the stove manufacturer’s instructions and that the appliance and chimney have been properly maintained. Testing the logs with a moisture meter will then help you establish whether the fuel itself is contributing to the problem.

What does Ready to Burn mean?

The Ready to Burn mark is a useful way to identify properly dried firewood. Administered by Woodsure, the certification confirms that qualifying wood fuel has a moisture content of 20% or less and gives customers added reassurance about the quality of the product they are buying.

Pearsons of Duns is an approved Woodsure Ready to Burn merchant, and our kiln-dried wood fuel is dried to below 20% moisture. This means it is ready to use when it reaches the customer, provided it continues to be stored correctly after delivery.

The legal requirement for Ready to Burn certification applies to certain sales of wood fuel for domestic use in England. It is not currently a legal requirement for equivalent sales in Scotland, but the mark remains a valuable and easily recognised assurance that the firewood meets the stated moisture standard. For customers in the Scottish Borders, it offers a straightforward way to compare more than price when choosing fuel.