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If you are fed up of having wet wood you may well be thinking that a move to using heat logs will actually be the best way forward, but there are just a few things you need to think about first.

What are heat logs?

Quite simply, heat logs are manufactured logs and can be of varying sizes but typically 6-8 inches long and 2-3 inches in diameter. Often referred to as briquettes although this term also refers to much shorter pieces which are used in chimeneas or barbecues in a similar way to charcoal briquettes.

They are made from a process of taking a finely chopped up raw material and compressing at very high compression rates up to 1000kg/m3. The higher the compaction the better the quality of log which should have a higher calorific value and hold its shape.

They are made from a huge range of raw materials although the common denominator will be the fact that it will always be made from biomass. Materials range from softwood and hardwood sawdust to peat, straw, paper, rice husk, rapeseed and there was even a company that used to make them from leaves!

Benefits of heat logs

Because they are made up from sawdust or similar very small pieces and compacted, the resulting log will be homogeneous i.e. consistent in composition and quality, and will always be very dry with a moisture content below 10%. Every log will therefore be the same and almost guaranteed in quality with a very high heat output. Many people regard them as a major step forward from standard wood logs, but this is generally when compared with wet logs. Being so dry, the energy output per volume is very high, therefore storing heat logs is efficient on space.

Disadvantages of heat logs

Firstly, if you try heat logs and find them to be a complete revelation from your standard logs, just bear in mind your logs may not have been very dry, so do try some really dry logs such as kiln dried to compare - you will find little difference in heat output.

Heat logs will always be packed in small waterproof packs, usually 10kg, so you cannot buy them loose in bulk, like logs. These packs, most importantly keep them dry as the majority of heat logs will absorb moisture very quickly causing them to expand and ultimately disintegrate. They must be stored in a dry area and you cannot afford to damage or pierce the bags as this will allow moisture to enter the pack.

Heat logs can often expand when being burnt, so be particularly careful when burning on an open fire as they can expand and fall out! The flame tends not to be as nice as with natural wood logs and because heat logs cannot be bought loose in bulk, they can be more expensive than traditional logs. Try and buy heat logs that carry the HETAS 'Quality Assured Fuel' logo to guarantee the quality and be careful not to buy heat logs that may have been made from contaminated wood waste i.e. waste wood that may have been treated, painted, or glued at some point. Also, be aware that some heat logs can produce quite a lot of ash.

These are really more for the occasional user, perhaps using the fire on the odd weekend, but less likely for the regular evenings and weekends user.


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