For many Australian households, particularly in regional and rural areas, wood heating remains an important source of warmth, comfort and energy security. It can keep a home warm during power outages and extreme weather, while sustainably sourced firewood provides a locally available, renewable fuel.
Wood heaters do, however, produce smoke and fine-particle pollution. The age of the appliance, its design and installation, the condition of the chimney, the moisture content of the firewood and the way the heater is operated can all make a significant difference to its emissions.
Replacing older, poorly performing appliances with cleaner, more efficient technology helps the environment and helps homeowners to heat their homes affordably and sustainably.
Comparing an old wood heater with a current certified model is a little like comparing an ageing diesel truck with a modern vehicle fitted with a cleaner, more efficient engine. Both use the same type of fuel, but the technology controlling combustion and emissions has changed considerably.
The Australian Standard is one of the strictest emissions standards in the world. Before 2015, the Australian particulate-emissions limit for wood heaters was 4.0 grams per kilogram of fuel burned. In 2015 the limit was reduced to 2.5g/kg and then to 1.5g/kg in 2019. This is set to be reduced even further to 1.0 grams in coming years.
The value of upgrading older installations was examined in Denmark’s three-year Clean Air Testzone project, funded by the Danish Environmental Protection Agency. From 2020 to 2023, researchers studied households before and after interventions that included new stoves, chimney improvements, electrostatic filters, draught optimisers and training in better burning practices.
Across the nine households with comparable before-and-after flue-gas measurements, average particle emissions fell by 40 per cent. Carbon monoxide declined by 25 per cent and organic gaseous carbon by 43 per cent.
When the researchers modelled the effects at a national level, they estimated that replacing Denmark’s pre-2008 stoves with current technology could reduce national particle emissions from wood heating by approximately 50 per cent. Replacing every stove with the latest technology was estimated to achieve a reduction of about 65 per cent. Danish Environmental Protection Agency, Clean Air Testzone
Although Danish conditions differ from those in Australia, the findings support a practical principle: targeting old and poor-performing heaters, chimneys and burning practices can produce significant gains.
Even a well-designed heater can produce unnecessary smoke if it is operated incorrectly. Using unseasoned wood, overloading the firebox or allowing the fire to smoulder reduces combustion efficiency and increases particulate emissions.
For cleaner and more effective heating:
Visible smoke can be a useful warning sign. Some smoke is expected during lighting and refuelling, but a correctly operating heater should not produce heavy, persistent smoke once the fire is established.
One of the main advantages of upgrading is improved thermal efficiency. A modern heater can convert a greater proportion of the wood’s energy into useful heat, reducing the amount of firewood needed to warm the home.
This is particularly relevant to houses with traditional open fireplaces. Open fires may be atmospheric, but much of their heat escapes through the chimney. They can also draw already-warmed air from the room and replace it with cold outdoor air.
Many existing brick fireplaces can accommodate an appropriately selected insert or inbuilt wood heater, subject to professional assessment of the fireplace, chimney, hearth and required clearances. This can bring an unused architectural feature back into service while providing more controllable and efficient heating.
Age alone does not determine whether a heater should be replaced, but an appliance more than ten years old may predate today’s requirements. It is worth arranging an assessment if the heater:
A professional assessment can establish whether maintenance, chimney improvements, better operating practices or complete replacement is the most appropriate response.
Wood heating will continue to have a role in many Australian homes, particularly in colder regional communities. The challenge is to retain its practical benefits while reducing its effect on neighbours, local air quality and the wider environment.
Whether you’re looking to install a new wood heater, require maintenance on your current wood heater, or need to talk to an expert, contact the team here at Highland Fires to answer your questions.