Thinking about renovating or retrofitting? Here's the things to consider to keep your home energy-efficient.
Renovating or retrofitting? The energy efficient Big Small House in Palm Cove by POD (People Oriented Design). Image Nic Granleese.

Renovating or retrofitting? Take inspiration from the energy-efficient Big Small House in Palm Cove by POD (People Oriented Design). Image Nic Granleese.

A person’s home is their castle. And just like Darryl Kerrigan, we want our homes to be comfortable, healthy, sustainable, inviting and inexpensive to run. So how do we get there? And what can we gain from renovating or retrofitting?

We asked the Research Lead of our Building Simulation, Assessment and Communication team, Anthony Wright, for tips on energy-efficient home improvements.

Back to the future: Retrofitting your home

Your house doesn’t need to be new to be energy efficient. You can retrofit your house, and get results, with minimal cost. Here’s how:

Choose and use your appliances wisely

Buying energy-efficient appliances is a good place to start. You’ve probably seen the energy rating stickers on fridges, washing machines and other appliances. The ‘star rating’ lets you know how energy-efficient the appliance is. You can search for highly-rated appliances and find out how much you’ll save on power bills.

We spend a lot of money on air con. Try turning on a fan to work with (or instead of) your air con, to provide a cooling breeze. It can make a huge difference. Fans are less energy-intensive and expensive. A ceiling or pedestal fan can use just 10 per cent of the energy of an air conditioning unit for the same room.

Install solar photovoltaic (PV) panels

More than two million Australian homes now have solar panels on their roofs. As panels become cheaper, more Australians are choosing to install them and reduce their bills and carbon emissions. Homes rated at eight stars and above can often generate all their own power from a standard six-kilowatt solar array over a year, and you can sell anything extra back to the grid.

Throw some shade

Plants can shade windows and cool your house. If you plant deciduous species, they’ll shade your house in summer, and allow sunlight in to warm your house when their leaves have dropped off in winter. If you don’t have a green thumb, don’t worry! Blinds, curtains, drapes and external awnings all help to keep heat out of your home in summer. Heavy drapes or external blinds can be one of the most cost-effective ways to keep your home warm in winter and cool in summer.

Seal, glaze and insulate

Australian homes are notoriously leaky. We waste a lot of energy cooling air in summer (or warming it in winter) only to let it all escape outside. You can install window and door seals easily in most older houses, by yourself. Hardware shops can tell you what you need to do. You can also install chimney dampers, replace exhaust fans with self-closing fans, seal up old wall vents and install covers on your evaporative cooling vents during winter.

Wherever you have removed the plasterboard or wall cladding, remember to install insulation. You might only be renovating the kitchen, but if the plaster comes off those walls, it might be a once-in-a-decade opportunity to install some insulation. While you have builders on-site you can also ask them to install ceiling or underfloor insulation or top it up if your existing insulation has compressed over time.

We lose 10-35 per cent of heat gains or losses through single glazed windows and doors. Retrofitting your house with double or triple-glazed windows and doors will make your house far more comfortable in extreme weather. It will also save you money and make your home quieter, as they block outside noise.

Don’t neglect the small stuff

Ask your plumber to install your new hot water service as close to taps as possible. Ask them to ‘lag’ the pipework (this is special piping insulation) with extra-thick lagging (25mm is good). You’d be surprised how much energy is wasted transporting hot water around in uninsulated copper pipes. Ask your builder to use any leftover insulation batts around the bath when they install the bath hob. It will keep the bath toasty for longer.

If you’re rewiring, make sure all your new lights use LED lamps and get a quote to install solar panels at the same time. Make sure any new windows you install have a low U value and that they open to catch the breeze. Think about external shading and internal drapes.

But it’s not just homeowners that can live in energy-efficient spaces. Canberra and Victoria have recently announced minimum energy efficiency standards for rental properties. All renters can use these tips to help stay comfortable.

  • Seal drafts wherever you can. You can do this by using door snakes. Ask your landlord if you can install door seals or hanging temporary curtains to zone rooms. Better Renting in Canberra has a great guide.
  • If appliances need replacing, ask your landlord to consider choosing high star-rated appliances.
  • Keep an eye out for solar schemes for renters, like this offer by Solar Victoria.
A woman sitting in front of large windows in her home. When renovating or retrofitting ventilation is an important point to consider.

The upcoming webinar (see details below) will feature Jenny Edwards, whose company, LightHouse, won the 2018 Master Builders Association Sustainable Construction Award with this Vasey House renovation. Photographer: Ben Wrigley.

Grab your hard hat: Choosing to renovate

Leaning on the renovation side of renovating or retrofitting? Renovating your house is a chance to change all the things that don’t work. Do your windows all face south? Maybe you can effectively turn the house around with new northern glazing. Does cold air flood the house every time someone opens the front door? Maybe you can add some internal doors to improve the zoning. No matter what you are altering, thinking about the basics early in the design process means your house will be more comfortable and keep your energy bills low.

Open up to orientation

The orientation of your home can have a big impact on your energy efficiency. Consider potential changes to let more sun in winter or keep it out in summer. This can cost nothing more than taking some extra care in design.

Take advantage of natural ventilation

Make sure your windows are placed to take advantage of cooling breezes and are WERS rated to keep you warm in winter and cool in summer.

Maximise insulation

This is one of the best investments you can make in the energy efficiency of a new or renovated home. If you’re adding, removing or altering walls, you have a once-in-a-lifetime opportunity to max out your insulation. You’ll probably never get a second chance to maximise the insulation of the new parts of your construction.

Consider thermal mass

Heavyweight materials like slab and brick can help to even out internal temperatures. A good designer or energy rater will be able to help you decide.

Get an energy rating early

Before you get started it’s important to know what you’re working with. Find out what your house will rate before and after your renovation and ask your designer if that is the best they can do. It is possible to bring an old leaky house up to modern standards with the right renovation.

Want to know more? Here are some resources to help you out:

Watch our 10 tips for keeping your home warm this winter.


  1. Many people have claimed the benefits of dark roofs in cold climates without providing any supporting data.
    I would like to see the data on how warming a dark roof is in winter in Victoria and Tasmania. In my estimation, dark roofs only heat minimally in winter and can only provide any heating after maybe 10 am and 4 pm on sunny days, because of the shorter daylight hours and the position of the sun being lower in the sky. The temperature of my terracotta, dark glazed roof reached 34C on a 24C winter day. I would say 24C is a rarity in colder climes. Even at that temperature, I can’t claim that my house was heated via the roof. I Imagine if I was was to get all my friends with their body temperature of 36C to lay on my roof, I doubt that there would be any heating capacity in that activity.
    I notice in my own home, the winter sun through north facing windows warms the house more. My dark roofed houses have all been the hottest houses in summer and also the coldest houses in winter, proving my point. I noticed, in my daughter’s Googong, NSW house, that the winter sun coming in through the north window increased the temperature by 2 degrees (21C) compared to other rooms with the Air-conditioning set to 19C for whole of house.
    I believe dark roofs will only perform better in colder areas, in the months between the equinoxes over warmer side of the year, due to longer hours of daylight (sunshine) and the sun being higher in the sky.
    Maybe the CSIRO researchers could conduct temperature assessments of areas other than Victoria and Tasmania, as a large proportion of the Australian community live in hotter climates where dark roofs are not recommended. See research into the western suburbs of Sydney, Brisbane and Perth as well as our very hot rural areas throughout Australia.
    I look forward to being proven wrong.

  2. Great Post! Thanks for sharing such beautiful information with us. Please keep sharing.

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