Sustainability Victoria puts a number on something most people only notice as a cold ankle in the hallway: 9 out of 10 homes in Victoria have unwanted draughts. The same page estimates that up to 25% of winter heat loss from existing houses is caused by air leakage.
Air leakage is the heat loss you never see. Insulation stays in the ceiling and glass stays in the frame, but the warm air itself slips out through gaps around sashes, frames and doors, and cold air is pulled in to replace it. You pay to heat air that is already on its way to the street.
The federal guidance agrees. YourHome, the Australian Government’s guide to sustainable homes, calls sealing “one of the simplest upgrades you can undertake to increase your comfort while reducing your energy bills and carbon emissions by up to 25%”, and its breakdown of where homes leak puts doors and windows among the biggest single culprits. In Tasmania, the state government’s guide to energy efficiency terms says the average heat loss from an unsealed home through gaps around doors and windows is around 15 to 25 per cent. Three governments, one conclusion.
Draught proofing is becoming law
Victoria is no longer treating this as a nice-to-have. Under the state’s new rental energy efficiency standards, from 1 July 2027 external doors, windows and wall vents in rental homes must have draught proofing installed. The government expects the reforms to save renters hundreds of dollars a year on their energy bills.
For owner-occupiers, the Victorian Energy Upgrades program already discounts weather sealing, with incentives of up to $700 available for an average house. When a government makes an upgrade compulsory for rentals and subsidises it for everyone else, it has stopped debating whether the upgrade works.
Why older timber windows leak the most
A double-hung sash window was built with clearances so the sashes could slide, and a century of timber movement widens them. Add worn beads, shrunken putty and a frame that has settled with the house, and a single window can carry several metres of gap around its moving parts. Multiply that by every window and external door in the house and the 9-in-10 figure stops being surprising.
The draught is only the most obvious symptom. The same gaps let in traffic noise and dust, and they are why sashes rattle in wind.
Sealing done properly
The state’s winter energy saving tips recommend fitting draught seals to windows and doors, and they add an important caution: homes with certain gas heaters rely on fixed ventilation, and sealing must never block the vents those appliances need. That caveat is a good argument for having the work done by people who assess the whole window, not just the gap.
Our draught and acoustic sealing fits concealed seals into the existing timber joinery, so the windows still open, close and slide as they were built to, without the rattles and without the cold ankle in the hallway. We seal the gaps that leak and leave the ventilation your home needs.
Where to start
If you can feel moving air near a closed window, or a sash rattles when a truck goes past, your home is one of the nine. These guides explain what sealing involves and what it pairs well with:
- The Quiet Truth About Sash Windows: Seal the Gaps and Your Glass Can Finally Work
- Draught & Acoustic Sealing
- An Easy Way to Understand Glass Performance
Or get in touch and we will tell you honestly how leaky your windows are.
Bring your windows back to life.
