Woodfires versus Gasfires

G Magazine

You can't beat a crackling open fireplace for atmosphere, but is it environmentally justifiable? And how does it stack up against a gas heater?


Hot stuff: Are wood or gas heaters the best option for warming your home (and not the planet)?

Credit: iStockphoto

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An open fire is a prime source of cosiness, but what about its energy efficiency? What about the trees? Is it OK to spend hours curled up in front of it, or should we be staring at gas-fuelled flames instead?

Paul Myors, energy efficiency specialist with Energy Australia, says an open fire is the most wasteful way to warm your house.

"Open fires are hopelessly inefficient,'' he says. "Eighty-five per cent of the generated heat will go up your chimney."

A modern wood-fed slow-combustion heater is a more efficient option, looks almost as pretty and is better at warming a room. And, according to Cameron Russell from Coonara Heaters, just 50 per cent of the heat is lost.

However, Russell says, gas heaters go one step better and only 20 per cent of the heat energy is wasted.

Cost-wise, gas beats wood hands down. Unless you live in a rural area with ready access to cheap firewood, you'll be looking at about $100 per tonne of wood. Combustion heaters usually burn a minimum of three tonnes over the course of winter.

Fuel facts

Unfortunately it's not as simple as just converting your old pot-belly stove over to gas. Gas is a fossil fuel, and therefore not a renewable energy source. It's not cheap to drill and has to be transported to your house.

Besides, natural gas is not available everywhere in Australia. Victoria has the highest rate of connection: 80 per cent.

Bottled LPG can get around this problem, but it is more expensive to get your bottle replaced continually than to have natural gas plumbed in.

Timber, on the other hand, is renewable and - apart from the trucking - essentially carbon-neutral.

Abbey Fireplaces manager Chris Bycroft says: "In terms of the lowest CO2 output, you can't get around a closed, slow-combustion woodfire. It beats any gas heater or reverse-cycle air-conditioner available by miles."

Of course wood takes years to grow, needs to be dried out for two seasons to optimise the energy output, and you need quite a bit of storage space. There are also questions about the impact on biodiversity and wildlife, and whether the trees come from sustainably logged native forest or from plantations.

On clear still days in regions such as Launceston, Canberra and Armidale, where many homes are heated with wood fires, a thick brown haze hangs over town - a result of all the smoke.

John Todd of the Commonwealth Department of Environment and Heritage estimates that 75 to 80 per cent of air pollution in Launceston can be attributed to wood heaters. Not only is this unsightly, but the so-called 'particle pollution' also poses health risks for children, the elderly and those suffering from asthma and lung diseases.

The verdict

A high-quality, slow-combustion woodfire heater is almost carbon neutral, but a host of other factors suggest there are more advantages to using gas.

Obtaining wood from a sustainable source is not always easy, and even if you have a ready supply you'll still need to consider the pollution the wood smoke creates.

Does your area suffer from particle pollution? Does smoke or mist tend to pool in your region? Is your area densely populated? Some locations, such as the inner city or valleys, are simply better served with gas heaters.

Those who have no access to gas and don't want to rely on wood as their main heating fuel can consider pellet fires as an open-fire alternative. These heaters use waste from saw mills compressed into pellets, which burn very efficiently and have low emissions.