A piece of wood contains two totally different fuels which burn in quite different ways.
The first parts to burn are the “volatiles”. These are the resins and creosotes which are converted to flammable gases and smoke by the heat of the fire. Volatiles contain almost all of the pollution content of the wood.
The second part of the wood is the ember residue left after the volatiles have been burnt. This is charcoal, and it contains the major part of the heat content of the firewood. Charcoal burns easily and produces little if any pollution emissions.
If your Ethos Woodfire is operating correctly most of the volatiles will burn completely, however if the fire and the ember bed is not kept hot enough they will not burn completely and exit via the flue as unpleasant chimney smoke pollution.
Take care to operate your fire so that it does not smoke and you will actually gain more heat from your firewood.
DIFFERENT WOOD, DIFFERENT BURNING
Use only dry, seasoned wood.
Our recommendation when choosing firewood is to select a combination of wood. A soft wood (pine is a great choice) is always good to start the fire and get a good hot base, then mix with a hardwood (eg. bluegum) to continue an efficient burn and achieve maximum heat output.
If you are only burning hardwood, we recommend increasing the amount of kindling used at start-up to assist building the hot base for efficient burning.
Order your firewood from a reputable dealer and specify a moisture content of not more than 20% by weight, or cut and stack your own firewood at least nine to twelve months in advance of use.
To be certain of wood moisture content we recommend splitting a log and using a moisture tester in the centre to confirm the inner moisture content. Moisture testers can be purchased affordably from most woodfire resellers.
Stack wood loosely in a well ventilated covered location so that air can circulate through the pile.
Do not burn wet wood.
Wet wood uses most of the heat it produces to dry itself before it can burn and this reduces the firebox temperature to below its efficient operating state.
Burning wet wood also causes excessive fouling inside the flue, requiring more frequent cleaning and dramatically reduces the amount of heat into the room.
Ensure your wood is dry for the best possible experience, with the highest heat output, the cleanest burning fire, and a reduced amount of cleaning and maintenence.
what you must not burn
In addition to wet wood, never burn coal, old man pine (old man pine comes from 25+ year old pine trees & contains high levels of resins and tars), plastics, sea driftwood, treated, painted or oily wood, particle board, laminates, household refuse, or any fuel other than ordinary approved firewood.
Burning these materials can emit poisonous, corrosive and hazardous fumes and can cause a build-up of toxic acids, creosote and dioxins which will seriously damage and reduce the life of the fire, congest the flue system and will invalidate your warranty.
The ideal size of firewood for your Ethos fire is approx 30 cm long and should be roughly 10-12 cm in diameter.
Two or three smaller split logs will burn as long, yet hotter and cleaner, than one large piece.
Avoid using pieces of wood larger than 12cm in diameter. When split in two larger logs will burn much cleaner and produce far more heat.