“There are many older Australian homes with NatHERS ratings as low as 1.5-stars,” says Elham Monavari, Head of Green Star Strategic Delivery at the Green Building Council of Australia.
“These homes are difficult and expensive to heat and cool, particularly while the climate is changing. All new homes must meet a minimum 7-stars and there are many examples of low-scoring existing homes being renovated to achieve 7-stars and above.”
An energy-efficient home is more comfortable to live in as they generally have a more stable internal temperature, meaning you’ll reduce the demand on energy networks and cut your carbon emissions. And when you sell, you should achieve a higher price.
In fact, “Domain research in 2022 found buyers can expect to pay $125,000 more for energy efficient houses and $72,750 more for units,” Monavari says. “Sustainable homes also attract more interest and sell faster.”
So, how exactly do you renovate your home to improve its energy efficiency?
1. Install solar panels and electrify
Australia has the world’s highest uptake of solar systems, with around 3.4 million rooftop installations. According to the Australian Energy Council, a typical solar pay-back period of a 5kW system in a major city is three to five years.2
If your home is a long-term proposition, you should investigate whether installing solar and a battery is a better option. Rebates may be available and you may be eligible for a personal loan for eligible energy-efficient products to reduce the upfront cost.
All-electric homes with solar can cut about 75 per cent off energy bills1, so if you have gas cooking, heating and water heating, you might consider replacing this with an electric alternative.
2. Consider thermal mass, insulation and double glazing
Thermal mass is the ability of a building material to absorb, store and release heat. If you need winter heating and summer cooling, high thermal mass can help passively heat and cool your home at a low cost.
“Major renovations should consider the geometry and home layout, ensuring main living areas and windows face north. Shading or eaves should be incorporated into the design to restrict summer sun,” Monavari says.
Insulation is a material that slows or prevents the flow of heat and is used to maintain a comfortable home temperature. It can help keep heat inside your home in winter and can help to reduce outside heat penetrating the home in summer. Roof and ceiling insulation can save up to 45 per cent on heating and cooling costs, while wall insulation can save around 15 per cent, according to the Climate Council's latest report.
Double glazed windows are the best solution to avoid heat loss, but solar blinds, curtains or louvres will help. Installing glazed glass and frames into windows, external doors and skylights will significantly improve thermal performance, meaning a more comfortable home and reduced heating and cooling costs.
3. Improve ventilation and draught sealing
Circulation of fresh air – through open windows, doors or ceiling fans – is important, as inadequate ventilation can cause condensation and unwanted levels of carbon dioxide. But you also need to prevent unwanted air movement and reduce summer heat gain and winter loss.
Simply sealing gaps can save 5 per cent to 15 per cent per cent of summer heat gain and winter loss. Start with weather seals around windows, doors and skylights, and retractable draught seals at the bottom of hinged doors. Poorly fitting floorboards and junctions between floors, walls and ceilings are other culprits, as are exhaust fans without draught stoppers and fireplaces without dampers.
4. Update energy-hungry technology
Your appliances account for around 25 per cent of home energy use. If yours are old, consider comparing their energy rating to newer products. The Federal Government’s energy ratings guide can help you calculate annual running costs.
- Fridges and freezer: For singles and couples, look for 250-380 litres; three or four people, 350-530 litres; and for bigger groups, 440 litres.
- Dishwashers and washing machines: Dishwashers that dry well use more power so are less energy efficient. Front-loading washing machines are generally more expensive but use less energy, water and detergent than top loaders.
- Clothes dryers: Heat pump condenser dryers work on the same principles as air-conditioners and are cheaper to run.
- Air conditioners: Reverse cycle air-conditioners are the most energy-efficient at heating and cooling but consider adding ceiling fans if you have warm summers. They’ll use just 10 per cent of the energy of an air-conditioning unit.
- Hot water heaters: Electric heat pumps are incredibly efficient and gather heat from outside and transfer this to your water tank.
For lighting, Monavari says, “switch to LED lighting. LED globes can last up to 10 times longer than old incandescent globes and use around 80 per cent less energy.” LEDs also cut replacement costs and reduce the number of light bulbs going to landfill.
Creating an energy-efficient home can seem overwhelming, but there are upgrades big and small which can make an impact. To help with the larger upgrades, you'll need experts onside, so find an architect, designer or builder with strong green credentials. You can ask them to arrange an energy rating of your existing home, and advise on what can be achieved from the renovation. You can find an accredited energy assessor to assess your home through the Nationwide House Energy Rating Scheme (NatHERS) webpage.
Ready to kick start your home electrification journey? Head to the CommBank home energy upgrades page to get started.
1https://renew.org.au/research/limiting-energy-bills-by-getting-off-gas/
2The Australian Energy Council Solar Report 2022, page 15
