If you type this question into Google, you’ll find lots of contradictory articles. Some will swear that wood is cheaper, while others are solidly on in the #GasGang. Many writers prefer to play it safe and say ‘it depends’ which it really does. It’s challenging to contrast usage in different households, so unless you do the experiment for yourself, running a gas burner and a wood burner then comparing results. But even then, your findings won’t be fool-proof, because there are so many variants.
For example, if you wanted to carry out this little exercise transparently, you’d have to run each fireplace for the exact same duration every day. You’d have to light them and douse them simultaneously, ensure they’re burning at the same temperature, then measure your fuel usage. Remember, any tweaks will influence your conclusion. If you turn on the fan, or open the windows, or switch off the flames and just use the light (you can do this with gas heaters), then your fuel consumptions shifts.
Before we dig deeper into this topic, let’s start with the short answer. Commonly cited stats claim that in Australia, you can go through $50 worth of wood in a year. During the same period – they say – you’ll pay $200 in gas bills. A different source claims 1 cord of wood (which costs $150) produces 18mmBtu. The amount of gas needed to emit that heat volume has a price tag of $188.50. This study cites natural gas, and doesn’t look into LPG.
Dollars and sense
The study also clarifies you can’t burn an entire cord (3m3) in one sitting. If you tried, a lot of the wood would be wasted, and if you apportioned your wood in smaller batches, you wouldn’t get the same amount of heat. In this sense, gas wins, because you can switch it off and on at will. You don’t have to think about how much wood is still unburnt, and you don’t have to do complex calculations to decide how much wood to load in your fireplace. On this basis, gas works out cheaper, because you can start-stop it in a way you can’t with wood.
This system lets you run your fireplace only as long as you need it, conserving the rest of the fuel for later. With wood, your only option is to use fewer logs or pellets, which means you may not get as warm as you’d like. The amount of wood you use also depends on the quality of your fireplace. You want a unit with a firebox, a heat bank, fans, and a good flue system. These work together to raise temperatures inside the burning chamber.
Their main function is to reduce smoke and emissions, making your wood furnace greener. The higher the temperature, the more thorough the combustion process. Smoke and fumes come from unburnt carbon, so these features minimise wastage. As a side effect, your wood burns longer before you need to top it up, creating further savings. An aspect we don’t consider is the cost of sourcing your fuel. You could buy gas from the depot or order a firewood service to deliver baskets on a pre-planned schedule. Costs depend on distance.
Little red riding hood
There’s a reason so many of us assume wood is cheaper. We think we can just wander into the woods behind our houses and collect twigs for the fire. Or maybe we can drive into a forested area or wild spaces and harvest our wood there, making it essentially free. If you’ve ever gone camping or tried to start a fire using stray twigs, you know how untrue this is. Commercial wood isn’t sourced from tree loppers, landscapers, excavators, or untrimmed shrubbery. It’s professionally logged from sustainable growers.
Once the wood is chopped, it has to be seasoned (i.e. dried). For softwood, this takes a few months, but for hardwood, it could take a year, sometimes two. And you want hardwood. Softwood burns too fast and gives off too little heat. When you use wood that isn’t properly dried, you’ll have a fireplace that’s all smoke and no flames. Incidentally, if you collect firewood yourself, you’re likely to pick softwood, because it forms the bulk of forest cover.
Softwoods mature faster, so we generally plant more of them, and even when they sprout naturally, their quicker growing time means they’re a larger percentage of the tree population. And if you go cutting branches off trees, you’re likely to pick fuel that is too wet for the job. With wood fireplaces, you have to add all these non-cash factors to the equation. With gas, just buy the bottle and go home. Plus you don’t have to clean out smoke and ash.