FAQs and Tips on Firewood and Coal

At Gibbs we sell firewood by the cubic meter (m3).

You may have heard of a “cord” of wood. A cord of wood is the American measurement for firewood.

1 cord = approx. 3.65 cubic meters (m3)

The amount of firewood needed by a household to get through a Southland winter can vary quite a bit.

Someone who depends on their log burner for all their heating and gets the log burner going as soon as the day begins, is going to use more wood than a household who has other forms of heating and only lights the fire in the evenings.

Also, if you have a multi-fuel burner and are using both wood and coal to heat your home, you will need less wood than someone with a dedicated log burner.

At Gibbs Firewood and Coal our experience is that households with a log burner generally use up to 10m3 of firewood for the winter season.

Well-seasoned firewood burns hotter, more cleanly, and lights more easily than greener, wetter wood.

All firewood contains some water. Freshly cut wood contains up to 45% water, and the longer and better the wood has been seasoned, the drier it will be.

Well-seasoned firewood generally is relatively lightweight and makes a clear “clunking sound” when pieces are knocked together.  All our wood is seasoned outside and then shed stored when the moisture content has reached 25% or less.

Burning green or wet wood is hard to burn, has a sulky flame, and doesn’t give off good heat. You also get more soot and steaming, which can result in your chimney being coated with sticky residue. This creosote build-up means more work for your chimney-cleaner and increases your risk of chimney fires.

For best results we recommend purchasing your firewood over the summer/autumn months and stacking it in a covered shed away from the weather to keep drying out until the next winter.

Gibbs Firewood and Coal stock a variety of woods. Each wood has its own characteristics and vary in terms of how easy they are to light, how much heat they put out, how fast or slow the wood burns, and how ‘sparky’ the wood is.

For more information about each type of wood, check out the Firewood section.

One tonne of coal is 1000kg.

If you’re not sure how much space this will take up, a good estimate is that one tonne of coal will equal about one cubic metre of space. If you’re not sure how much coal your coal bin will take, measure it up and come and have a chat with us. We can help you make the right decisions about the type and quantity of coal that is right for you.

At Gibbs we sell coal in a variety of grades and measures. To see more about what is on offer, check out the Coal section.

Coal can only be burned in coal burners or in multi-fuel burners.

Coal burners and multi-fuel burners have fundamental design differences to log burners and wood stoves. In order to burn well, coal needs to be burned on a grate, with air circulating both above and below the fire. This enables the coal to burn hot enough to be an effective heat source. The grate also allows the ash to fall down below the fire while it is still burning. Ash build-up can smother a coal fire.

Log burners and wood stoves, on the other hand, are designed with a solid base, with the air source at the top of the burning chamber. This suits the way that wood combusts, and the smaller amount of ash that you get with burning wood (especially in high-efficiency burners) means that the ash doesn’t get in the way of a good wood fire. In fact, a layer of ash on the bottom of a log burner can be a good thing.

If you’re not sure what type of fireplace you have in your house, check to see if there is an open grate at the bottom of the burning chamber, and a way to clear ash out from below it. If there is, then you can likely burn coal in it. If not, then best stick to firewood.

If you’re still not confident, take some photos of the fireplace with your phone, both inside and out, and showing the controls and vents if you can. Then bring them along to Gibbs Firewood and Coal and have a chat with us. We’ll help you find the right fuel for your fireplace.