NET BAGS smart way to buy Firewood
When choosing firewood for burning there are two significant factors:
- Moisture content
- Wood density
Moisture Content: dry wood produces more heat than wet. The wetter the wood, the more energy of the wood is used to dry itself before it can burn, the less is left for heat production. This means that if you reduce the water content of your log by half, you nearly double the amount of heat produced by the log.
Seasoned firewood contains 50 – 60 % of moisture
Air dried firewood contains 30 – 35 % of moisture
Kiln dried firewood contains 15 – 20 % of moisture.
The moisture content of wood has the greatest effect on net Calorific Value (CV).
When buying firewood, it is common for the seller to let you know whether they are from Hardwood or Softwood tree species. The general difference is that hardwood is much denser than softwood. Dense wood will burn for longer than less dense woods, this means you will need fewer ‘top ups’ to keep a log stove burning (more kilowatt hours – kWh). Ash and Oak calorific value is much higher than Birch and it burns longer.
Value for money:
Very important part is to understand the volume of firewood you are buying for the same amount of money. Certainly the moisture affects the weight of firewood. Thus the best way to compare the volume is in volumetric weight. Another important part is to know whether firewood is neatly stack up or dumped into the bags.
Some examples: Content of a whole pallet (2 m high) is just short of 2 m3 stacked wood, which is around 3.5 m3 loosely dumped wood. Content of a half pallet is 1 m3 stacked wood, which is around 1.75 m3 loosely dumped wood. That means: 1.2m3 bulk bag contains only 0.68 m3 of neatly stacked firewood or 1.6m3 bulk bag contains only 0.91 m3 of neatly stacked firewood.
What is healthy for your Chimney?
Burning wood in your fireplace results in deposits of tar and creosote forming in your chimney. Dry logs results in the less water vapour being emitted up the chimney (it’s the water vapour that contains the tar and creosote) as well as a much higher temperature in the flue and stove. It’s only at less than 50 degrees (typically) that these deposits form.