Burn dry wood and stay warm

Using dry wood in your woodburner or open fireplace will keep you warmer this winter, and it’s better for the air, says Environment Waikato air quality scientist Dr Nick Kim.

“When buying wood, it pays to ask about its condition. How dry is it, how long has it been dried, what type is it and is it split?” said Environment Waikato air quality scientist Dr Nick Kim.

“Softwoods normally need 6-12 months to dry, and hardwoods like gum can take up to 18 months. If the wood is split, it should be no more than 10-15 cm thick.

“As we enter winter, people might be tempted to burn wet wood, or wood that hasn’t been properly dried. Burning wet wood gives you less heat and more pollution,” Dr Kim said. Smoke contains harmful particles called PM10, that are not visible to the human eye but small enough to get into human lungs and cause health problems. In winter, most of these harmful particles come from wood burned in homes, not from industry or vehicles.

“Dry wood keeps you warmer, and burns more cleanly. One study has shown that the simple act of drying the wood before it is burned can reduce PM10 emissions by three to five times.”

Whether wet or not, some materials should never be burned in home fires. These include treated wood, manufactured wood products such as particleboard, MDF and plywood, and plastics. These materials can give off a range of toxic substances, which can be harmful to people’s health or the environment, and can damage fireplaces, woodburners and chimneys. Burning old treated wood is particularly dangerous, because this can release arsenic in to the air, and result in arsenic contaminated ash in the fireplace.

For more information, including some questions to ask when purchasing firewood, visit www.ew.govt.nz/firewood.
Environment Waikato would like to acknowledge its local partners in Tokoroa’s Warm Homes Clean Air project – South Waikato District Council, the Raukawa Trust Board and the South Waikato Pacific Islands Health Committee – whose work has already resulted in improvements to Tokoroa’s air quality.