Compressed wood, or Briquettes are made from waste wood produced as part of the furniture or other wood-related buisness', in some cases the wood is collected from skips. The burning of wood is usually considered a low-carbon alternative to fossil fuel, because trees absorb carbon as they grow.
Briquettes burn hotter and cleaner, are cheaper to buy, and are easier to store and handle. They are also denser than most of the naturally occuring firewood. The manufacturing process ensures that the raw material is highly and uniformly compacted, meaning you burn fewer briquettes than natural firewood, to achieve the same heat output.
As there are no chemicals, additives or binders used to hold the logs together, they can also be used in BBQs and Chimneas.
Briquettes are big in Europe, however, largely untried by fire users in the UK. It is recommended that new users should try a selection, in order to see which works best in their stove or fireplace. Most can be broken in half but not all, this is useful if you have a smaller stove.
The Co-op started selling briquettes in 2012, and are now their biggest seller. The majority are from Eastern Europe particularly Latvia and Estonia.
They are available in a variety of shapes from a number of providers, and in initial tests by Guardian Money show they perform fantastically well in Wood Burners. One briquette can last up to 4 hours, and those who use them more frequently will find they save around £150 a year when compared to buying conventional logs.
Briquettes have to be stored in a dry place, so that they don't expand rapidly when they get wet. When they burn they leave 1% of their original volume as ash, this means the stove does not need emptying as much.
Eco-Logs.co.uk suggest that there can be as much as 2/3 times more heat energy contained in an Eco-Log than an ordinary piece of firewood of equivalent mass. Rowland Park (Wood fuel Co-operative), suggests that once people start trying them, they will soon stop buying logs locally, due to the heat they give out, they make less mess and are easy to store. The only considered negative to these briquettes are that the flame tends not to be as nice as with natural wood logs (CertainlyWood.co.uk 2014), and because heat logs cannot be bought in bulk, they can be more expensive than traditional logs.
Stove manufacturers always recommend their users to burn wood with a moisture content of less than 20%. The moisture content of most briquettes is 10% or less, this means they burn better and cause fewer chimney and flue problems. Also these lower levels of moisture radiate more heat on a weight for weight basis than natural firewood.