The 6 star minimum energy efficiency requirements in the Building Code of Australia apply in Western Australia from 1 May 2011, with a 12 month transition period to allow time for consumers and industry to adapt to the new requirements.

What is 6 Star Rating?
The energy efficiency measures for new homes refer to the star-rating system, where the relative energy efficiency of the house design is modelled by computer software with ratings from zero to ten stars.

Passive Solar Design
The easiest way to ensure a home is energy efficient is, firstly, to design it to suit the local climate. By taking advantage of the free natural warmth from sunlight and cooling from breezes you’ll reduce your need to use costly energy for artificial heating and cooling. This is referred to as passive solar design or design for climate.

Why Passive Solar Design?
Building a home using good design principles can save energy, water and money, while creating a more enjoyable and comfortable home.

In a larger sense, passive solar design helps reduce our carbon footprint. The average Australian household emits around 14 tonnes of greenhouse gases per home each year. It may be scary to think that we have contributed to our environment’s current and future demise. Being more aware now we can make educated decisions to lessen our impact and in fact create a positive change through our actions.

Passive Solar Design Principles

• Orientation
A home that is well positioned on its site delivers significant lifestyle and environmental benefits. Correct orientation assists passive heating and cooling, resulting in improved comfort and decreased energy bills.

• Shading
Shading of glass is a critical consideration in passive design. Unprotected glass is the single greatest source of heat gain in a well insulated home.

Shading requirements vary according to climate and house orientation.
In climates where winter hearting is required, shading devices should exclude summer sun but allow full winter sun to penetrate.

This is most simply achieved on north facing walls. East and west facing windows require different shading solutions to north facing windows.

In climates where no heating is required, shading of the whole home and outdoor spaces will improve comfort and save energy.

• Passive Solar Heating
Passive solar heating is about keeping the summer sun out and letting the winter sun in. It is the least expensive way to heat your home.

This could be achieved by:
Northerly orientation of window areas
Passive shading of glass
Thermal mass for storing heat
Minimising heat loss with insulation, draught sealing and advanced glazing
Using floor plan zoning to get hearting to where it is most needed and keeping it there

• Passive Cooling
Passive cooling is the least expensive means of cooling your home. It is appropriate for all Australian climates.

Four key approaches to achieve this include:
Envelope design for passing cooling
Natural cooling sources
Hybrid cooling systems
Adapting lifestyle

• Insulation
Insulation is an essential component of passive design. It improves building envelope performance by minimising heat loss and heat gain through walls, roof and floors.

• Thermal Mass
Externally insulated, dense materials like concrete, bricks and other masonry are used in passive design to absorb, store and re-release thermal energy. This moderates internal temperatures by averaging day/ night extremes, therefore increasing comfort and reducing energy costs.

• Glazing
Windows and glazing are a very important component of passive design because heat loss and gain in a well insulated home occurs mostly through the windows.
With good passive design, this is used to advantage by trapping winter heat whilst excluding summer sun. Cooling breezes and air movement are encouraged in summer and cold winter winds are excluded.

• Skylights
Well positioned and high quality skylights can improve the energy performance of your home and bring welcoming natural light to otherwise dark areas.

Cost of Passive Solar Design
The cost to implement passive design ranges from net saving through to a significant up-front investment that will be repaid throughout the life of the home.

Upgrading an existing house to achieve passive design outcomes is usually more expensive than if it was developed from Scratch. We therefore encourage you to speak to our architect to incorporate passive design principles in the new home design stage.