Many people in Australia heat their homes with wood heaters. Wood heaters can be a significant source of local air pollution during the winter.
Woodsmoke can particularly be a problem on very cold, still nights because:
- more people leave their wood heaters burning overnight
- people overload their heater with wood, starving the fire of oxygen and causing it to smoulder and produce a lot of smoke
- smoke hangs in the air at ground level without a breeze to blow it away.
Impact on human health
Woodsmoke contains a range of pollutants that are harmful to human health, such as particulates, nitrogen oxides, carbon monoxide, volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). Some pollutants from wood heater smoke, such as particulates and formaldehyde, are carcinogenic. Chronic exposure to woodsmoke can also cause heart and lung disease. Pregnant women, children, older people, and people with respiratory illness are especially vulnerable to the health impacts of woodsmoke.
Reducing smoke from wood heaters
To reduce the amount of smoke your wood heater produces, you should:
- burn only dry, seasoned, untreated wood
- wait for the fire to establish before adding extra fuel
- open the air controls for a few minutes before adding fuel
- after reloading, wait until the fire is burning before turning the air controls down
- use small or medium pieces of wood, and avoid overloading your heater, as this will starve the fire of oxygen and cause it to smoulder.
States and territories provide best practice guidance for using wood heaters in their jurisdictions. For example, NSW EPA has a range of resources available on how to correctly use wood heaters.
Buying and installing a new wood heater
If you are buying a new heater, make sure it complies with the latest Australian wood heater emissions and efficiency standards. These standards are set by Standards Australia and are mandatory in most states and territories.
Check your heater has a compliance plate showing it meets:
- AS/NZS 4012:2014 Domestic solid fuel burning appliances – Method for determination of power output and efficiency
- AS/NZS 4013:2014 Domestic solid fuel burning appliances – Method for determination of flue gas emission.
Due to improvements in design and technology, many heaters available in the market produce less emissions than the maximum set by the Australian standards. Where possible, buy a wood heater that produces the lowest level of emissions.
A new wood heater must also be installed according to the AS/NZS 2918:2018 Domestic solid fuel burning appliances - Installation.
Local regulations about where and how wood heaters and chimneys can be installed also apply. As these can vary, contact your local council to check before installing a wood heater. Some councils keep a register of licensed installers who will certify that heaters are installed to the standard.
Alternatives to wood heaters
Where possible, choose an alternative method to heat your home.
Gas heaters and reverse cycle air conditioners (or heat pumps) are a great option to use in urban areas. They are generally more efficient and also avoid transporting firewood to urban areas, saving energy and emissions.
Biomass heating options, including pellet and grain heaters, are more efficient and produce fewer emissions than conventional wood heaters. Pellet fuel heaters burn pellets of compressed sawdust. This is the waste product of sawmilling processes. These heaters use a hopper to feed pellets into the firebox. Pellet heaters have very low emissions and are almost smokeless.
Improving the thermal efficiency of your house may also reduce the need for heating. You can regulate the temperature of a house through:
- wall and ceiling insultation
- sealing of draughts
- thick curtains
- using thermal mass in floors and walls.