The layout of the house in relation to the sun, and the use of features and materials that don’t maximise the use of solar energy, are important in keeping your house at the right temperature while saving on energy costs.
Passive design is the control of ventilation and temperature without using any products that consume energy or money (such as heaters, dehumidifiers or fires).
Good passive design includes:
- House orientation – positioning the house to allow maximum sun in the winter and coolness in the summer. This includes deciding which rooms you want to be the sunniest.
- Solar energy – using solar panels for water heating.
- Use of shading elements – for example, wide eaves protect from the sun in summer and provide increased weather protection in winter.
- Placement and glazing of windows – the larger windows should face the sun to capture the warmth, use glazing to stop heat escaping, and have shading to limit summer overheating.
- Ventilation – using window joinery that allows ventilation, such as security catches allowing windows to remain partially open, or vents in the joinery.
- Insulation – to reduce heat loss.
- Thermal Mass – using heavy building materials to store solar energy and limit overheating during the day but then release energy during the night to provide heating.
A note about solar power
On average there are about 2000 hours of sunshine a year in New Zealand, although this varies by location.
Solar energy is most commonly harnessed for heating water using solar panels mounted on the roof. Electricity can also be generated directly using photovoltaic cells mounted wherever they can best capture solar energy.
Many of the local councils also have information about using solar power.