Bringing back the wood stove

Nana technology. It's the quirky term encompassing all those things your granny does - preserving fruit, darning socks, knitting jumpers and making jams and chutneys. Now there's another nana technology on the comeback - the cooker, or traditional woodburning stove.

Most cookers in New Zealand from 1872 onwards bore the name of Shacklock and came from the Dunedin workshop of Henry Shacklock, who designed them to run on cheap lignite coal. With a performance superior to imported models, Shacklock's ranges were hugely successful.

These days the more eco-friendly - and council compliant - cookers and stoves run on wood fuel. It has a net zero CO2 emissions profile and, provided the wood is well seasoned, emits very little smoke at all (see below).

A traditional cooker may seem like a quaint notion, but it's impossible to argue with low heating bills (the cost of your firewood), free hot water and dinner at the same time.

Some models have up two ovens - which work at different temperatures - generally one for standard cooking, the other a cooler option for slow cooking or simmering stews. It's possible to get a glass door in contemporary models, but it doesn't affect cooking performance. Unlike the days of old, ovens these days are self-cleaning models.

On top of the cookers is a large hotplate which will boil or simmer, and you'll probably dispense with the electric kettle through the winter while you use the plate to heat water for your cup of tea.

Free hot water is provided by way of a wetback - a system whereby water pipes flow through the rear of the cooker and can provide up to 400 litres of steaming hot water.

It will require a dual plumbing system, but the cost of that is quickly paid off when you consider that hot water makes up a third of your power bill.

It's important to choose a cooker which is 3kW or more and keep in mind for efficiency the closer the cooker is to the hot water cylinder, the better. A 5kW model can provide all the hot water you'll ever need.

Hot water can also be provided by a wetback from a woodburning stove, but again, the same rules apply - you'll need a decent-sized unit, and have a hot water cylinder close by. Some cookers and stoves can be used to heat water for underfloor heating as well as your hot water needs. For this you'll be looking at 5kW plus models.

Construction

Cookers are made either from cast iron, welded steel plate, or a combination of both.

Cast iron is the tradition material for stoves, having been used for hundreds of years. It's a robust, attractive material which will give years of service, but must be treated correctly. Moisture is the enemy, which can cause rust damage. Its benefits also include excellent, even heat distribution.

Plate steel construction is also growing in popularity and offers a less traditional, more contemporary look. The steel can either be plate steel, or lightweight sheet metal. The former offers a more robust option. Again, moisture should be avoided at all costs.

Fuel

Provided your firewood comes from a renewable source, it has a net zero carbon emissions profile. This is because CO2 is sequestered into the tree during the growing process and released again when you burn it. If a tree is replanted, the CO2 will be sequestered again, and so on.

It's important to 'season' wood well - it should have had at least a year out of the rain to ensure it is completely dry. The result is smoke-free, hot-burning wood.

Black marks appearing on the firebox glass door or excessive smoke can mean your wood is not properly seasoned.

Driftwood should never be burned in a cooker or wood stove - it has a high salt content which causes corrosion.

Regulations

There are safety issues associated with any appliance that contains fire, so you will need to apply for a building consent before installing, relocating or substantially replacing a solid fuel heating device.

You will also need to apply for a Code Compliance Certificate after the work is completed to confirm it has been carried out in accordance with the description in the building consent.

Further, all appliances must meet a particle emissions rate if they are installed in urban or coastal areas. Find out more at aucklandcouncil.govt.nz.

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