Heat pumps have become the hottest thing in home heating thanks to their energy efficiency, but modern wood fires are now giving them a run for your money.
In a semi-rural area like north Rodney, firewood can often be sourced very cheaply, if not for free, so the idea that heat pumps are cheaper may be an urban perspective.
North City Heating consultant Jason Smith says wood burners are cheaper for producing heat, but incur an initial outlay cost.
“There is the cost of the fireplace which starts from $1900 and then the consent and any additional flashing you might require on your house. I just completed a job for $4200 in the Kaipara district, which is the most expensive place to get a consent,” he says.
The cost of firewood in the area can range from $120 per cubic metre for a hot mix of pine, macrocarpa and blue gum from Wyatts Haulage, to just $55 for offcuts from the Cypress Sawmill, or even free from the side of the road or Facebook.
A typical household running a fireplace every evening could expect to burn through 10 cubic metres during the winter season.
According to Laser Electrical Silverdale managing director Bryan Fairgray, the cost of installing a heat pump is not dissimilar to woodburners at $2500 to $3000, but he says they are incredibly efficient.
“A 2kW heat pump will produce 6kW of heat so it is using a third of the energy it is putting out. If you install a ducting system they can also heat the whole house,” he says.
“The heat pump is also much quicker at taking the chill off the air because it blows heat around the room. I have a pump and a fireplace, and I use the pump when I get home because the fire takes about an hour to get started.”
“I pay 50 cents an hour to run the heat pump and it costs me $350 in a season for firewood. I daresay the wood is cheaper over the hours, but there is more work involved with chopping the wood and cleaning the soot.”
In terms of heating a space, a wood fire puts out considerably more energy with the smallest and least expensive burners producing 11kW and larger models up to 26kW.
Pat Neems from Wyatts Haulage Firewood says fires are popular in the area, particularly in older houses because the dry heat can burn off the humidity in the air, instead pushing it around.
“We bring in 500 cubic metres of firewood at the beginning of winter and that will get us through three quarters of the season,” he says.
Another consideration is carbon emissions. While you might expect that burning something for fuel would be worse for the environment, modern wood burners have come a long way.
In the Rodney district, a wood burner is required to produce less than 1.5 grams of particulate per kilogram of wood that burns. A modern wood fire achieves this with a hotter, ‘cleaner’ burn, which produces less smoke and particulates.
However, it is impossible to make a direct comparison between the emissions of a wood burner and a heat pump, due to the variation in how much wood might be used in a single burn and the variation in the means of electricity generation.