How to Find Draughts in Your House

Australian houses built before the 1970s often leak far more air than modern standards allow. A CSIRO study shows that 1950s timber‑stumped homes can be up to 20 % less energy‑efficient, and drafts account for roughly 20 % of a winter heating bill. Uncovered windows alone may lose up to 40 % of heat in colder months. The problem is especially acute in southern states, but even northern “troppo‑architecture” homes suffer when doors and windows stay open.

Detecting drafts without expensive equipment

Before hiring a professional, homeowners can perform a quick visual and tactile inspection. The following low‑cost techniques reveal the most obvious leaks:

Hand‑feel test: Walk around the perimeter on a windy day and feel for cold spots on walls, windows, and doors.
Whistling test: Listen for high‑pitched noises around window frames and vent openings.
Candle or incense test: Light a candle near suspected gaps; a flickering flame indicates airflow.
Paper test: Hold a thin sheet of paper against a door or window; if it slides easily, the seal is inadequate.

These observations give a rough idea of where the biggest leaks are, but they do not quantify the overall airtightness of the envelope.

Quantifying air leakage with a blower‑door test

The most reliable method is a blower‑door test. A calibrated fan depressurises or pressurises the house while a sensor measures the resulting air changes per hour (ACH). The test provides a baseline ACH figure and highlights the most problematic locations – typically around windows, doors, service penetrations, and ceiling vents.

Typical ACH values for older Australian homes range from 10 to 30 ACH, compared with the 5 ACH target recommended for new builds. A lower ACH translates directly into lower heating demand and reduced utility bills.

Prioritised draught‑proofing actions

Once the leaks are identified, address them in order of cost‑effectiveness. The following list follows the hierarchy suggested by the research brief.

Windows: Install heavy, lined curtains or pelmets, seal cracks with silicone or weather‑strip, and consider double‑glazing or low‑emissivity films. Expected heat‑loss reduction: up to 30 %.
Doors: Apply adhesive weather‑stripping, attach door sweeps or interior “snakes,” and fit external seals with wipers.
Appliance & service penetrations: Seal gaps around built‑in heaters, fireplaces (using dampers), kitchen sinks, and under‑counter appliances with expanding foam or caulk.
Vents & exhaust fans: Temporarily close fixed ceiling or wall vents and fit removable covers on exhaust fans during winter.
Evaporative coolers: Fit magnetic strips or winter covers to block airflow when the unit is not in use.
Other gaps: Seal skirting‑board joints, brick‑to‑trim interfaces, and visible cracks with silicone or foam, taking care around gas appliances.
Floor insulation: Lay rugs or carpets over timber floors, especially on raised stumps, to disrupt convection currents.
Solar gain: Keep north‑ and west‑facing blinds open during daylight to capture passive heat.
Insulation hierarchy: Prioritise ceiling insulation (R4.0 rating) for the best return on investment, then under‑floor and wall insulation. Wall retrofits may require moisture‑management strategies.
Appliance upgrade: Replace older central heating with split‑system units for zoned heating and lower operating costs.

Each measure can be implemented independently, but the cumulative effect often exceeds the sum of individual savings.

Cost‑benefit table

Measure	Typical cost (AUD)	Expected heat‑loss reduction	Payback period (years)
Weather‑strip doors & windows	$150‑$300	5‑15 %	0.5‑2
Heavy curtains / pelmets	$200‑$500	10‑20 %	1‑3
Double‑glazing retrofit	$1,200‑$2,500 per window	20‑30 %	5‑10
Ceiling insulation (R4.0)	$800‑$1,200	15‑25 %	2‑4
Blower‑door test (professional)	$300‑$600	Provides baseline ACH	—

Numbers are averages for typical single‑family homes in Victoria and New South Wales. Local labour rates and material prices may vary.

Rebates, regulations and professional help

State and federal rebates are available through the Australian Government’s Your Energy Savings portal. Concession‑card holders may receive free draught‑proofing materials. While the National Construction Code requires sealing of the building envelope, it does not prescribe a specific airtightness level, making professional testing and targeted upgrades essential for optimal performance.

For detailed guidance on sealing windows, see our window draught‑proofing guide.

Learn more about eligible rebates at the energy rebates information page.

Why sealing drafts matters

Reducing uncontrolled airflow improves indoor comfort, lowers heating bills, and protects structural components from moisture‑related damage. A tighter envelope also enhances the effectiveness of any subsequent insulation upgrades, delivering a higher return on investment.

Homeowners who systematically identify and seal drafts typically see a 10‑30 % reduction in winter heating costs, depending on the severity of the original leakage and the measures applied.

Next steps for homeowners

Perform a quick draft inspection using the hand‑feel, candle, and paper tests.
Schedule a professional blower‑door test to obtain an ACH rating.
Prioritise low‑cost measures (weather‑stripping, curtains) before moving to higher‑cost upgrades (double‑glazing, ceiling insulation).
Check the Your Energy Savings portal for applicable rebates and concessions.
Document improvements and re‑test after major upgrades to verify ACH reduction.

Following this roadmap helps homeowners achieve measurable energy savings while maintaining the historic character of older Australian homes.

Looking to improve thermal efficiency without compromising design? Contact our team to evaluate the right window and door upgrades for your project.

Assessing Long-Term Energy Savings

When investing in home upgrades, initial installation costs are only part of the equation. Homeowners must weigh upfront expenses against long-term utility bill reductions, thermal performance gains, and potential property value increases.

Material Quality and Durability Standards

Choosing high-performance materials—such as energy-efficient window glazing, advanced insulation fibers, or weather-resistant roofing—ensures structural longevity and minimizes ongoing maintenance overhead.

Assessing Professional Installation vs. DIY

While minor cosmetic updates can be handled independently, major efficiency retrofits require specialized expertise. Professional installation ensures compliance with local building codes and protects manufacturer warranties.

Project Timelines and Weather Windows

Home improvement schedules vary based on project scope and seasonal conditions. Proper planning ensures that exterior renovations or weatherproofing initiatives are completed efficiently without disrupting daily routines.

Maximizing Rebates and Financing Incentives

Many regional and federal programs offer tax credits or rebates for energy-efficient home upgrades. Evaluating these financial incentives early can significantly offset total project costs.

Warranty Coverage and Quality Assurance

Reliable service providers back their installations with comprehensive workmanship guarantees and manufacturer warranties, giving homeowners long-term peace of mind.

Ultimately, a successful home improvement project should enhance your property's daily comfort, boost energy efficiency, and provide long-lasting value for years to come.