If you own or rent one of Australia’s 6m-plus homes built 30 years ago or more, the words “coldest start to winter” can be especially depressing.

These older dwellings are leaky, rely heavily on heating and cooling, and emit more carbon than modern homes. This exacerbates health problems, spikes bills and notches up emissions. “Before time” houses, built prior to the National Construction Code’s introduction of energy standards in 2003, typically score just 1.8 stars on the 10-star nationwide house energy rating scheme. New builds are generally rated between 6 and 7 stars.

So what can be done to reduce the energy consumption and carbon emissions of these pre-2003 homes?

The perceived complexity of bringing these older buildings up to modern energy standards means, according to experts speaking to Guardian Australia, “there is a real bias towards building new”.

But retrofitting homes for better energy efficiency often doesn’t require dramatic structural changes to reap thermal, financial and environmental benefits. It’s about finding ways to use less energy to accomplish the same tasks. A few simple modifications and appliance adaptations have the power to reduce energy usage without harming your hip pocket.

Easy wins

For the building scientist Jenny Edwards, starting with the simple act of draught sealing and topping up your ceiling insulation is a no-brainer. Damming up gaps and cracks around windows, skirting boards and doors keeps your home warmer in winter and cooler in summer. It’s also one of the most cost-effective ways for owners and renters to improve the energy efficiency of their homes.

“Air leaks in the shell of your home make a massive difference to the amount of energy you use,” Edwards says. “Australian houses are very leaky by international standards, and it’s very easy, with usually a matter of a few hundred dollars, to dramatically reduce the amount of air leakage.”

A basic caulking agent, coupled with window and door sealing tape, can be bought at your local hardware store for less than $20 and make a significant impact on reducing air leakage.

Like gap sealing, ceiling insulation is another critical factor that maintains temperate comfort and reduces energy consumption by preventing air escaping. A report by the Insulation Council of Australia and New Zealand in 2009 estimated that, before 2004, approximately 40% of Australian homes did not have ceiling insulation; it stands to reason that many older homes have very little, if any. CSIRO experts say the cost of insulating ceilings varies but estimate the cost of installing ceiling insulation to range from $1,800 to $2,800 and that shifting from no insulation to a well-insulated home could save 45% on heating and cooling costs.

Finding air leaks in your home can be as simple as carefully passing a damp hand or a lit incense stick around the fringes of common leak spots. If the smoke is sucked away or you feel a cool draft on your hand, you’ve found a leak. Many local libraries now also have thermal camera kits available to borrow, which are excellent for revealing insulation gaps and air leaks by showing how warm or cool those spots are in your home.

Dr Gill Armstrong, the buildings project impact manager at Climateworks Centre, recommends installing heavy curtains and applying window insulation films to single-glazed windows to improve heat retention. Using dry mode (identifiable by a water drop symbol) on your reverse cycle air-conditioner or investing in a dehumidifier for wet spaces like your bathroom or laundry can reduce condensation and mould, while planting deciduous trees outside the house itself can provide external shading and therefore cooling in the warm months, without compromising warming sunlight in the winter.

Edwards acknowledges that these micro refurbishments don’t elicit the same enthusiasm as big-ticket items such as rooftop solar systems and home batteries, which consumers have come to associate with energy efficiency. But the appetite for expert guidance on these less-visible enhancements is growing – Edwards’ own firm, Light House Architecture & Science, alone conducts 150 home assessments in Canberra a year, without even needing to advertise.

Switch to electric

With household appliances accounting for roughly 25% of home energy use, making the switch to all-electric appliances can reduce overall energy consumption and costs – as new electric appliances such as induction stoves are generally more efficient – but also reduce carbon emissions, particularly if power is generated from renewable sources such as solar, wind and hydro.

Retrofit projects such as Breathe Architecture’s Park Street, shortlisted in the sustainability category of this year’s Houses awards, are a masterclass in the light-touch approach; the 1970s apartment building had gas replaced with an all-electric suite and only light tweaks to flooring and fixtures, leaving the structure and aesthetic details virtually unchanged.

A 2023 report by Climateworks Centre in partnership with CSIRO revealed that, with a combination of rooftop solar, thermal enhancements and electrification of water and appliances, households can slice up to an estimated $2,195 a year from their energy bills.

If solar is out of reach or you’re renting, Jeremy McLeod, co-founder and director of Breathe, has simple advice for energy efficiency: “The single biggest thing you can do in your home is buy 100% GreenPower.” A government-accredited program, GreenPower will not change the energy usage of a home but it enables homeowners and renters to reduce overall carbon emissions by investing in renewable energy via their regular electricity retailers.

Trivess Moore, an associate professor at RMIT’s school of property, construction and project management, recommends people start with a residential efficiency scorecard assessment.

The government-backed assessment provides households with a star rating, a detailed analysis of how their home and appliances use energy, and a practical improvement pathway.

“You’re getting a qualified expert to give you information about what you should do and in what kind of order,” Moore says.

An assessment typically costs between $250 and $500, based on the size and location of your home and complexity of the assessment (Victorians are eligible for rebates under the Victorian energy upgrades program).

Before an assessment, experts suggest thinking about how you live in your home. Consider who spends the most time at home, which spaces you spend the most time in, which rooms receive northern sun, how you use your appliances and whether you adjust your behaviours or habits based on temperature.

Many banks and lending organisations are now offering green and low-cost loans for household energy performance upgrades, taking the sting out of upfront costs for appliances, solar, renovations and new builds. State governments also offer a variety of home energy rebates.

Before you move in

Prospective buyers and renters are seldom informed about the energy rating of the homes they inspect. A report by Environment Victoria in 2020 revealed 91% of real estate agents surveyed could not confirm the energy ratings of properties they sell or lease. Educating yourself on what to look for and attending inspections armed with a checklist is a crucial step.

Moore recommends taking note of heating and cooling systems, the condition of the windows and doors, and curtain thickness. He also encourages would-be tenants to ask rental agents whether the landlord is open to energy efficiency upgrades.

“Having that discussion upfront around the likelihood of some of those things might be a way to gauge whether future improvements are likely,” Moore says.

While Jenny Edwards admits it’s difficult in the current housing climate, she encourages house hunters to look for northern orientation; if this isn’t achievable, consider whether it’s possible to adapt rooms that do enjoy northern sunshine into a home office or alternative living area or zone down larger areas of the home to reduce energy consumption.

“People get distracted by the big sexy glamorous projects which cost a fortune, regardless of the energy efficiency or not, when we need to be focused down on [simple, cost-effective changes],” she says.