Heating your home with a Woodburner

Wood burners can be an extremely efficient form of heating when the owners have access to free wood. Without access to free wood, modern wood burners cost between 14-20 cents / kWh to run. If used correctly, they can be comparable to a heat pump in terms of energy efficiency. It is important that dry untreated wood of an appropriate size is used. Wood burners are not as convenient as other forms of heating as they cannot be switched on and off, they require manual labour and cannot be set to a timer. Many people in New Zealand prefer the type of heat produced and the ambience compared to other forms of heating, sitting in front of the fire on a cold night with can be one of the benefits of otherwise cold and dreary winters.

Most commonly, people will install a free-standing fire unless they are replacing an old open fire. Free-standing fires tend to be more efficient than inbuilt wood fires. When choosing which wood burner to buy the size required will depend on the size of the home and the climate. For example, a larger wood burner may be excess to requirements in warmer parts of the country such as Whangarei. Wood burners can either be convector or radiant; convectors heat the air immediately around them and are better suited for well insulated non-draughty houses. Radiant heaters “shine” heat on anything near them which will be more suited to houses that do not have insulation and do have draughts. If installing a wood burner, thought should also be given to installing a heat transfer system as this will help to recirculate the heat throughout the house rather than just heating one room. Heat transfer systems work by automatically detecting uneven temperatures and pushing warm or cool air through insulated ducting to either warm or cool rooms.

Wood burners must have a building consent before they are installed – and cannot be completed retrospectively. This is because local councils have different rules surrounding the types of wood burners that can be installed. The National Environmental Standards requires that all wood burners installed on a property under 2 hectares meet an efficiency of at least 65% and an emissions rate lower than 1.5g/kg. Ideally, the fewer emissions they release the better, this is especially import in big cities like Auckland and Christchurch. If wood burners are installed without a consent, this can void insurance.  If you are purchasing a home a home with a wood burner installed it is vital council records are checked to confirm compliance. It is important to maintain wood burners by getting a professional to clean the flue at least once a year, poorly maintained wood burners can also void insurance. Maintenance also includes keeping the firebox clean and repairing/replacing any broken parts. Chimneys must be kept structurally sound by correctly repairing any cracks or gaps and installing seismic restraints to reduce the risk of them causing damage in an earthquake.

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