The DOLMAR MM-100 moisture-content meter for timber: an invaluable aid to heating safely and economically with wood

Burning damp wood is highly uneconomical and damaging to the environment. This is because the moisture that is still in the wood has to be vaporized, which requires a lot of energy. Precious thermal energy is lost in the process – which means it is no longer available for heating your home.

Furthermore, burning wood that is too damp is bad news for chimneys. The lower combustion temperature results not only in higher emissions but also in an increased build-up of soot and tar in the chimney and progressive creosoting. Both these factors increase the risk of a chimney fire.

Ideally the moisture content of firewood should be between 12% and 20%. Depending on the species of timber, this means that firewood needs to be stored for at least 12 months and up to 30 months. Air-dried timber with a residual moisture content of up to approx. 20% has a calorific value of around 5.0 kW/kg. In the case of freshly felled timber with an average residual moisture content of approx. 60%, the calorific value falls to around 2.6 kW/kg. What this means in practice is that nearly double the quantity of wood is needed to maintain the same heat output.

The moisture content of stored wood can now be measured quickly and easily with the aid of the new Dolmar MM-100 moisture-content meter. The pair of test probes are simply pushed gently into the surface of the timber, and the moisture content can be read off on the LED display.