How to improve the energy efficiency in older Australian homes

Scott Bradley's 1960s Perth home is a typical vintage Aussie abode — full of charm, but hot in summer and cold in winter.

"It's an older house, brick and tile, and so in the winter there's draughts and in the summer the outer areas get really hot," he said.

For the past three decades it's been mandatory for new homes to meet a minimum energy efficiency standard — these days it's seven stars.

But an estimated 70 per cent of Australian homes were built before the introduction of these standards.

The estimated star rating of these houses is less than three stars out of 10.

Improving old homes

In a bid to try to lift that, the federal government is investing $32.7 million to extend the Nationwide House Energy Rating Scheme (NatHERS) to older homes like Mr Bradley's.

Under that program, assessors provide participating households with home energy rating certificates, which include tips and information on what upgrades are possible for their home.

The money is being used to train and accredit more assessors, and further develop the energy rating software tools.

Assistant Minister for Climate Change and Energy Josh Wilson said even improving a home from three to five stars could reduce the energy needed for heating and cooling by around 40 per cent.

"You can't fix what you can't measure," he said.

"So by extending this rating system to existing homes, we create the opportunity for people to understand the energy performance of older homes and also get guidance on how to improve it, bring down energy costs, make their house more liveable, and decrease emissions."

Mr Bradley recently got an assessment done to figure out how to make his place more comfortable and cheaper to run.

DIY solutions

While solar and batteries were among the possible solutions offered up — some were much more affordable, sometimes even DIY.

These include things like switching to LED lights, draught-proofing the floorboards, walls and windows, and sealing bathroom exhaust fans.

These tips all came from CSIRO home energy assessor Kel Lupis, who gave Mr Bradley's home a 2.6 energy star rating.

"Some things come with a price tag, but not everything needs to cost a lot of money — draught-proofing is cheap to do," he said.

"Insulation in the ceiling space is another one to look at because it is a high impact, low-cost addition."

The expansion of NatHERS to existing homes could eventually lead to energy star ratings becoming a mandatory disclosure at point of sale or lease — something recently trialled in New South Wales.

Real estate agent and sustainability expert Chiara Pacifici said research had shown that people were willing to pay a premium for a home with a high energy star rating.

"Currently people know more about the energy efficiency of their fridge and freezer than they do their own homes," she said.

"My number one [piece of] advice is, when you're looking at leasing a property or buying a property, ask the real estate professional about the energy performance of the home."

Comfort benefit

Home owner Jason has been slowly retrofitting his modest 1990s home in Perth's southern suburbs.

He's spent tens of thousands on a range of upgrades including double-glazed windows, solar panels and home batteries.

His home now has a home energy rating of more than seven stars.

"The biggest winner for us is comfort, and the [other] side to that is energy savings and being able to save money," Jason said.

The cost of a home energy assessment alone is around $300 — that's before you even start spending the money on implementing the tips recommended by the assessor.

But Mr Wilson believed it was something that will have broad benefit.

"When you get to the point where home energy ratings become a requirement at the point of sale or lease, it will be one of those things that people shop around for," he said.

It would be up to states and territories, he said, to decide if and when to make energy efficiency a mandatory disclosure.