A home energy audit sounds like something you pay a specialist to do. It isn't. Most of the checks that reveal real problems require only a torch, your hands, and about three hours of focused attention. The savings from finding and fixing even two or three issues can add up to hundreds of dollars a year, and the environmental payoff runs well beyond your electricity bill.
What a DIY home energy audit actually covers
A professional audit uses blower-door tests and thermal imaging cameras. A DIY version skips those tools but still catches the things that cost most households the most money: uncontrolled draughts, inadequate insulation, inefficient appliances, and lighting that hasn't been updated in a decade. Work through each zone methodically rather than drifting from room to room.
Grab a notepad and divide it into four columns: location, problem, fix, and estimated cost. You'll come back to that list at the end.
Start with the thermal envelope
The thermal envelope is every surface between your conditioned living space and the outside: walls, ceiling, floor, windows, and doors. Gaps in this envelope are where heated or cooled air escapes.
On a cold morning, hold your hand near every external door frame, window sill, skirting board, electrical outlet on an external wall, and the point where the floor meets the wall. Moving air means a gap. Light a stick of incense near any suspect area and watch the smoke: if it wavers, you've found a leak. Check the ceiling manhole too. An uninsulated or unsealed manhole is one of the most common and most overlooked energy losses in Australian homes.
Write down every draught location. Most can be fixed with draught-seal tape, door seals, or outlet gaskets. None of those repairs cost more than a few dollars per point. If you want to go further with sealing and weatherproofing, the practical steps in our guide on how to make your home more energy efficient without a renovation sit naturally alongside what you'll find here.
Check your insulation honestly
Ceiling insulation is the most impactful insulation in an Australian home because heat rises. If your house was built before 1990 and has never been retrofitted, there's a reasonable chance the ceiling batts are compressed, missing in patches, or simply below current standards. Poke your head into the ceiling cavity with a torch and look. Batts should be fluffy, evenly laid, and at least 100mm thick (R2.5 minimum; R4 or above is better for Victoria).
Under-floor insulation matters in homes with a raised timber floor. If the floor feels cold underfoot in winter, it probably has none. Note it on your list.
Audit your hot water system
Hot water typically accounts for around 25 per cent of a household's energy use. Touch the pipes leading out of your hot water system. Warm pipes in winter mean heat is escaping before the water reaches a tap. Pipe lagging costs very little and fits in minutes.
Check the thermostat on your storage system. Many are factory-set between 70°C and 75°C. The recommended setting is 60°C: hot enough to prevent legionella, cool enough not to waste energy heating water beyond what you need. If your system is more than 10 years old, note it as a future upgrade candidate. A heat pump hot water system in Victoria currently qualifies for rebates under the Victorian Energy Upgrades program.
Walk through your appliances
Open the fridge and check the door seal by closing it on a piece of paper. If the paper slides out without resistance, the seal is failing and the fridge is running harder than it needs to. A replacement seal costs around $30–60 and takes 20 minutes to fit.
Note the age of your dishwasher, washing machine, and any second fridge or freezer. Appliances older than 12 years are often dramatically less efficient than current models. You don't need to replace them today, but knowing their age helps you prioritise when something fails. Check the Australian Energy Rating database to compare the running costs of your current models against newer equivalents before you buy.
Check your dryer too. If you have one, note how often it runs. A folding drying rack or an outdoor line costs nothing to operate. It's worth considering whether the dryer is a habit or a genuine necessity.
Lighting and standby loads
Walk through every room and count incandescent or halogen globes. Both are still common in older homes and use roughly 5 times the energy of an equivalent LED. Replacing them costs $3–8 per globe. Write down the count.
Standby power is the energy devices draw when they're switched off but still plugged in. Televisions, gaming consoles, chargers, and set-top boxes are the main culprits. A smart powerstrip or the habit of switching off at the wall can cut standby loads by 5–10 per cent of your total electricity use.
Heating and cooling: the biggest lever
Heating and cooling account for 40 per cent or more of home energy use in Victoria. Check your reverse-cycle air conditioner's filter. A clogged filter forces the unit to work harder and can reduce efficiency by 15 per cent. Cleaning a filter takes two minutes with a vacuum.
Check whether curtains or blinds are thick enough to act as an insulating layer at night. A single-layer sheer curtain does almost nothing for thermal performance. Heavy-lined curtains or honeycomb blinds can cut window heat loss by 40 per cent in winter. If you're looking for low-impact ways to furnish your home while building these improvements, sourcing shopping second hand like a professional is a practical way to find quality curtains and textiles without the cost of buying new.
Turning your notes into a priority list
At the end of the walkthrough, you should have a list of 10–20 issues. Now sort them by the ratio of impact to cost.
- Draught-sealing: low cost, high impact. Do these first.
- LED globes: low cost, moderate impact. Do them on the next hardware run.
- Appliance filter cleaning: zero cost, immediate return. Do it today.
- Ceiling insulation upgrade: higher cost, very high long-term impact. Plan for this within 12 months if it's missing or degraded.
- Hot water upgrade: significant cost, but Victorian rebates reduce the outlay considerably.
Don't try to fix everything at once. Two or three changes done well, starting with the free ones, will shift your bills faster than a scattered attempt at everything simultaneously.
One audit, then a habit
Run this audit once a year, ideally at the start of winter. Homes change: new appliances arrive, seals age, insulation settles. A quick 90-minute repeat check once a year keeps the list short and the fixes cheap. The first audit is the hardest because you're building the baseline. After that, you're just maintaining it.