Passive design for energy efficiency

Passive design features

Passive design is design that takes advantage of a building’s site, orientation, climate, and building characteristics to minimise the amount of energy required for heating, cooling and ventilation.

Good passive design includes:

• good house orientation – positioning to allow solar access, wind and temperature- induced breezes when and where needed, year round
  
• use of shading elements – for example, wide eaves shade when sun is high in the sky as well as providing increased weather protection
  
• glazing placement and size – to ensure that solar energy gets to where it’s needed most, yet also correctly shaded to minimise overheating
  
• ventilation – for example, using window joinery that allows ventilation, such as security catches allowing windows to remain partially open
  
• insulation – to reduce heat flows both into and out of the buildings “shell”. This assists with heating and cooling
  
• thermal mass – using heavy building materials which receive direct sunlight in the colder months to store daytime solar energy to then release it during the night to provide space 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 can be used for heating water using solar (thermal) panels mounted on the roof. Electricity can also be generated directly using photovoltaic cells mounted wherever they can best capture solar energy.

If you’re thinking about going solar, you’ll need to do your homework first. Check out our mystery shop of solar panel installers here.

Further reading

• Passive Solar Design – a fact sheet that provides key strategies for practical, low-cost and comfortable high performance home designs, which are easy to build, use and maintain.
• http://www.level.org.nz/passive-design/

This page was put together with the help of BRANZ.