Wood & Pellet Heaters

 

Wood can be an excellent fuel because it is a renewable energy source, if sustainably harvested. However, air pollution from wood fires and the transport of firewood to urban areas are environmentally detrimental.

About 20% of Australian homes use wood for heating, but the wood is often obtained from unsustainable sources.

If you have a wood heater, use only sustainably-harvested wood to avoid habitat destruction and rare species extinction, and do not use treated timbers that may give off toxic pollutants when burned.

Burn wood only in high efficiency, low emission heaters. Open fireplaces lose up to 90% of the heat straight up the chimney, making them the least efficient of all heating technologies.

Even worse, the hot air rising up the chimney draws large amounts of cold air into the room to replace it, making whatever heating effect the fireplace has even less effective.  On the other hand, a well made and properly installed slow combustion heater can achieve up to 60% efficiency, assuming it is operated correctly.

Using wood for heating - what to do

•   Use only an AS/NZS4013 approved slow combustion wood heater
• Use clean, dry wood from sustainable sources
• Keep the air damper open to allow the wood to burn efficiently with minimal pollutants
• Fill the firebox to a reasonable height to allow good airflow around the wood, making sure that there is at least a 25mm airgap between each log
• Keep the flue and the inside of the wood heater clear of ash, debris and creosote buildup
• Regularly check seals around the heater doors and ash removal trays.
• Close off flues and chimneys when they are not being used-this helps to prevent unwanted drafts.

What not to do

• Don't use damp or scrap wood that you happen to find lying around, without knowing its origins
• Never use treated pine or wood that may have been painted with toxic substances
• Don't overfill the firebox or else your wood won't burn efficiently
• Don't load up the firebox and turn the air damper down to let the fire smoulder all night
• Don't let the creosote build up in your flue-you risk having a flue fire.

Pellet heaters

Pellet heaters work in a very different way to a conventional wood heater. Instead of loading up a firebox with large chunks of wood and controlling the airflow, a pellet heater is controlled by giving the fuel all the air it can use and adjusting the rate that the fuel is fed into the firebox.

Pellet heaters don't use wood in its natural form, but rather, small pellets made from wood or agricultural waste, such as rice husks.

The waste is granulised, dried so it contains almost no moisture, and compressed into tiny pellets of a consistent size and density. They have a large surface area compared to their volume, and so burn quickly.

The pellets won't spontaneously combust, so there has to be an ignition source to get the ball rolling. This is in the form of a small electric heating element.

Once the pellets are burning, the element usually switches off, but electricity is still used to run the fans and electronic control system.

Because these heaters use electricity, you will have to pay for an electrician to connect it.

Even though the wood pellets burn almost completely, they do produce some ash which has to be regularly removed from the heater.

Also, the auger system can make some noise, so it is recommended you listen to the heater operating before you buy it.