How to improve the star energy rating of your home

Anyone who has made a trip to a contemporary display home in recent times will know contemporary, eco-friendly home design is all about reaching for the stars – six stars, that is. Indeed, a six star energy rating is the way of the future as energy efficiency in homes becomes a priority.

"The star energy rating relates to the heating and cooling required to make a house comfortable," explains Doug MacPherson from Sustainability Victoria. "The less heating and cooling required, the greater the [number of] stars. The balance of things you need to consider varies depending on the location of the house."

Upping your energy star rating with insulation

For example, Melbourne is a heating-dominated climate, so most of the effort that would go into conditioning a house in this location would centre on heating. Key things to include would be good insulation, especially in the walls and ceilings, and heavy materials (i.e. concrete and brick) inside the house, to help store heat during the day. Insulation and the use of heavy materials can also help regulate the temperature in summer.

Consider the aspect of your home

To maximise the star energy rating of your home, it is also important to make sure that the winter sun gets into living areas – these should be on the north side of the house and have good north-facing windows – and to keep the heat lost through windows to a minimum. This can be done by having efficient windows and keeping overall window sizes small. Draughts can be minimised by using weather strips on doors and windows and by installing self-sealing exhaust fans.

Take a look at your glass

Keeping window sizes small will help to keep summer heat out; having shading on windows is also important at this time of year. "Correctly sized eaves and external blinds help here," says Doug.

One issue that often compromises the performance of a home’s star energy rating and consumption is the prevalence of large areas of glass, says Doug. "People often want a view … other times it's a desire to have a light and airy home. These can be achieved in a six-star home, but need some thought. Do you really need glass all the way from the floor to the ceiling? If you raise the sill and lower the head height of a floor-to-ceiling window by 300mm each, you've reduced the heat loss and gain by about 25 per cent."

A house with a six star energy rating can be achieved relatively easily – most architects are now au fait with what's involved in designing energy efficient homes – but you need to be working on it right from the beginning of the design process. "Starting from an existing plan and trying to get it to six stars can often end up difficult and expensive," says Doug.