EPA Urges Proper Use of Wood Heaters

A well-engineered solid fuel heater will still emit excessive smoke if it is burning inappropriate fuel. Freshly cut wood contains about half its weight in water. It does not burn properly, so does not produce as much heat as dry wood. This causes excessive smoke and wastes money – you are essentially paying to boil water.

Freshly cut wood should be split and stored undercover (eg under a roof to keep it dry) and in a well ventilated area. Stacking your wood loosely off the ground in a criss-cross fashion allows air to circulate freely, and maximises airing.

The minimum time recommended to store freshly split wood before burning is 6–12 months. Dry, seasoned wood should make a 'crack' when you hit one against the other, rather than the dull thud of a freshly cut log.

One of the requirements of the Air Quality Policy is that any firewood sold for use in a solid fuel heater must have a maximum moisture content of 25% dry weight (measured in accordance with AS/NZS 1080.1:2012 Timber – Methods of test, Method 1: Moisture content).

It is generally accepted that fuel with a moisture content greater than 25% dry weight doesn’t burn as efficiently, leading to  substantially higher emissions (including increased PM2.5 particle pollution) contributing to impacts on human health and the environment. Fuel with a moisture content greater than 25% dry weight is not ‘fit for purpose’.

One way to ensure your firewood is properly seasoned and sustainably harvested is to buy it from a Firewood Association of Australia accredited sustainable supplier.

Hardwoods such as Mallee and Red Gum are preferable to soft woods such as Pine. Softwoods tend to contain more resins, which create smoky odours, deposits in your flue, and exhaust gases.

The first phase of burning wood can release very high concentrations of smoke. A vigorous flame will burn off most of the smoke before it goes up the flue, so keep those air vents open.

Use kindling wood, paper or firelighters to start the fire. Add larger pieces of seasoned wood when a bed of red-hot coals is established.

Once the wood is burning fiercely, you may then turn down the controls so that the fire will give out a comfortable warmth.

Build smaller fires by adding small amounts of wood regularly and providing plenty of air. Avoid having one or two large logs smouldering in the fire with the air controls turned down.

Keep the air vents open for 15–20 minutes after you reload the fire each time.

Low burning and smouldering can produce up to 10 times more smoke than a brightly burning fire. Such burning will not get the best heat value out of your wood.

Excess smoke may result in creosote, tar and soot building up in your flue. This can lead to the following:

To help your fire burn brightly, never over fill the heater with wood. Most heaters burn better with three or four smaller logs rather than one or two large logs. Stack them loosely so that air can circulate. 

Do not set your wood heater’s convection fan too high (if fitted) as this will cause excessive cooling of the firebox.

Do not pack your fire and leave it on a low setting overnight or when you go out, as it will smoulder and produce a large amount of smoke.

Insulating your home, closing doors and drawing curtains will help to conserve the heat from your fire while it is operating and also after it has gone out. However, you should always have some fresh air flowing into the room in which your heater is located to provide air for combustion.

Go outside and look at your flue. If after 20 minutes there is still smoke coming from your flue you may need to adjust the fuel or air vents to get a better fire.

With a little practice and care, your heater can be relatively smoke free even in the first few minutes after lighting!

Newer models of solid fuel heater are engineered to be more efficient and burn more cleanly, decreasing emissions to the atmosphere. If you have an old heater that produces a lot of smoke or does not have a label showing it complies with Australian Standards AS/NZS 4012 and AS/NZS 4013, you could consider upgrading to a compliant solid fuel heater, or switch to an alternative form of heating.

The minimum time recommended to store wood before burning is 6-12 months, depending on whether it’s soft wood or hard wood, and the wood should be split, stored undercover and in a way to maximise airing.

A well-engineered solid fuel heater will still emit excessive smoke if it is burning inappropriate fuel. This could lead to a breach of the requirement not to emit excessive smoke under clause 12 of the Air Quality Policy.

The policy prohibits the sale of firewood or solid fuel with a moisture content greater than 25% (dry weight). At this moisture level wood begins to burn inefficiently leading to increased emissions (such as increased PM2.5 particle pollution), which contribute to impacts on human health, amenity and the environment. Fuel with a moisture content greater than 25% (dry weight) is not ‘fit for purpose’ and it can be said that with higher moisture content the consumer is paying for both the weight of the water and the wood/fuel.

Under clause 13 of the Air Quality Policy it is an offence for a person to sell firewood with a moisture content greater than 25% (dry weight). Burning wood with a high moisture content could lead to a breach of the requirement not to emit excessive smoke under clause 12. Wet wood will need to be stored for 6–12 months before it can be used. If you believe you have been sold wet firewood, contact the EPA or your local council for assistance. 

It is important that you operate your heater correctly. Your solid fuel heater should only produce smoke for a short time when you first light it and when you add extra fuel. Excessive smoke can become a serious environmental nuisance for neighbours, affecting not only their health but also home comfort. An easy way to see if your heater is emitting excessive smoke is to go outside and check your flue or chimney. Compare the smoke from your flue to the chimney checker.

You are required to prevent excessive smoke from being emitted from your heater under clause 12 of the Air Quality Policy. This clause also sets out a test for ‘excessive smoke’:

Smoke emitted from a solid fuel heater is excessive if:      

All solid fuel heaters sold in SA must comply with Australian standards, so when buying a solid fuel heater make sure it has a compliance plate showing it meets the Australian Standard for efficiency (AS/NZS 4012:2014 Domestic solid fuel burning appliances – Method for determination of power output and efficiency) and emissions (AS/NZS 4013:2014 Domestic solid fuel burning appliances – Method for determination of flue gas emission). It must also be installed according to the Australian Standard (AS/NZS 2918:2001 Domestic solid fuel burning appliances - Installation).

The SA Government does not have any plans to ban solid fuel heaters, however they are not recommended in high density living, metropolitan areas as the smoke may impact on neighbours.In some areas it may not be practical to install and run a solid fuel heater due to local topography, which can influence the dispersion of smoke and may increase the risk of smoke impacting on neighbours. 

While the EPA cannot recommend a particular brand of solid fuel heater you should ensure that any heater you purchase complies with AS/NZS 4012:2014 and AS/NZS 4013:2014. Solid fuel heaters that meet these standards will display: THIS HEATER COMPLIES WITH AS/NZS 4012:2014 AND AS/NZS 4013:2014 on a plate on the back of the heater.

Newer solid fuel heaters are engineered to burn cleaner and operate more efficiently, decreasing emissions to the atmosphere.

The Air Quality Policy requires that all new domestic solid fuel heaters sold and installed in South Australia comply with the Australian Standard for efficiency (AS/NZS 4012:2014) and emissions (AS/NZS 4013:2014), or with a standard from an overseas jurisdiction that is approved by the EPA as being equivalent to, or more stringent than, the Australian Standard. Heaters made to these standards will carry a label showing their certification.

Make sure your heater is the appropriate size for the area you plan to heat. Your local retailer should be able to provide this type of advice. A solid fuel heater running at its optimum design capacity, will produce the right amount of heat for the room or house and produce the least amount of pollution. A model that is too large for your room will need to be turned down to reduce the heat output, and this immediately reduces efficiency and increases the amount of wood smoke. Operating a heater with a smaller load of firewood than it is designed for to reduce the heat output will decrease the amount of pollution, however it will also reduce the heater’s efficiency.

Look for the following design features when looking for a heater that will burn the fuel completely and produce less smoke:

Combustion system Good design and operation will ensure enough air is supplied to burn off smoke and volatile wood components in the secondary combustion zone. This will generate more heat in the room and reduce air pollution. 

Combustion system of a wood heater

Efficiency measures how much of the heat value contained in the firewood is extracted and delivered into the living space, so the higher the efficiency the less wood is required to produce the same amount of heat.

The efficiency rating is on the back of all solid fuel heaters, it will display: MAXIMUM AVERAGE HEAT OUTPUT BURNING HARDWOOD and OVERALL AVERAGE EFFICIENCY BURNING HARDWOOD (%). The EPA recommends you do not buy a heater that does not display this information.

All solid fuel heaters installed in SA must have a label showing they comply with Australian Standards for efficiency (AS/NZS 4012:2014) and emissions (AS/NZS 4013:2014), they must also be installed according to the Australian Standard (AS/NZS 2918:2001). This is a mandatory requirement and a breach of this provision is an offence.

Check with your local council before installing your solid fuel heater as it may require approval under building codes.

Installation should be conducted by a qualified tradesperson, according to manufacturer’s instructions and in accordance with AS/NZS 2918: 2001 Domestic solid fuel burning appliances – Installation.

When fitting a rain protector use a cowl that does not impede the upward flow of smoke, such as a concentric rain excluder (vertical discharge flue) or a rotating wind directional cowl if you live in a heavy rainfall area. Rain protectors such as a ‘Chinaman’s cap’ should not be used as they restrict the upward flow of hot gases and reduce the dispersion of smoke.

The height and position of chimneys and flues is an important consideration when it comes to reducing wood smoke and preventing it entering neighbouring houses. When installing a solid fuel heater the chimney must be high enough to allow the particles and combustion gases to disperse.

The EPA recommends that the flue be 1 metre higher than the ridge line of the roof and any structure within 15 metres to minimise the potential risk of causing wood smoke and odour nuisance. If the flue is lower than the ridgeline the smoke can be caught up in the downwash or turbulence on the lee side of the building and can directly enter the house or a neighbour’s property. 

Clause 10 of the Air Quality Policy requires that solid fuel heaters are installed in accordance with AS/NZS 2918:2001, which includes minimum requirements for flue height and position.

In some areas it may not be practical to install and use a solid fuel heater because the chimney would need to be very high to achieve this minimum clearance. The example below shows houses at different elevations. Installation is not recommended for houses A and B unless only smokeless fuel or a catalytic reactor stove complying with AS/NZS 4012:2014 and 4013:2014 is used.  

Wood smoke can become a serious environmental nuisance for neighbours, affecting not only their health but also home comfort.

The EPA encourages neighbours to resolve problems between themselves or through mediation. We all need to give greater consideration to the impacts we might be having on our neighbours.

If your neighbour’s solid fuel heater is producing smoke or odour that is affecting the enjoyment of your property, you can do something about it.

Tell your neighbour what the problem is You may find that your neighbour is unaware that their solid fuel heater is affecting your property.

Don’t get angry Anger, frustration and fear can impact upon how we react to annoyance. By confronting the issue immediately you can avoid the risk of ill health caused by compounding stress. Less stress places you in a better frame of mind to constructively discuss your concerns with your neighbour. Most people are responsible and willing to help if asked.

Approaching your neighbour Be calm not angry, focus your discussion on the issue, not the person. Help your neighbour to resolve the issue.

If approached by a neighbour Don’t be defensive or offended. Remember—they are not there for a personal attack, it is ‘the issue’ that they are concerned about. Be friendly and work with your neighbour to find a solution.

Contact your local council Your council can also deal with the issue utilising a range of options including the prevention of excessive smoke requirement and test set out in the Air Quality Policy.

Mediation processes Sometimes both parties choose to seek assistance through free mediation that includes an interpreter service. These services can be accessed via the White Pages under ‘Mediation’ or community mediation services.

Taking civil action If the parties have been unable to resolve the issue informally through negotiation or mediation, either party can take civil action (under section 104 of the Environment Protection Act 1993) through the Environment Resources and Development Court.

For further information please call the EPA on 8204 2004 or 1800 623 445 (freecall for country users).

When seeking ways for neighbours to live in harmony, we advise that legal action should only be considered as a last option.