Highest-ROI energy upgrade
Draught Proofing Australia — 2026 Cost, DIY Guide & What to Seal First
Uncontrolled air leakage is 15–25% of your heating and cooling bill. Draught proofing costs a fraction of insulation and pays back in 1–3 years — here's the full playbook.
2026 draught proofing costs
| Scope | Cost (2026) | What's included |
|---|---|---|
| DIY starter kit | $50 – $150 | Door seals, foam tape, chimney balloon |
| DIY whole-home | $150 – $400 | All doors + windows + exhaust dampers + wall-vent covers |
| Professional seal | $800 – $2,500 | Trade install + self-closing exhausts + downlight covers |
| Blower-door verified | $2,000 – $4,500 | Pre/post ACH50 test + guaranteed leakage target |
Prices exclude replacement windows or new exhaust fans.
Where to seal first — ranked by impact
- 1.Exhaust fans & rangehoods — retrofit self-closing dampers. Biggest single leak in most homes.
- 2.External doors — brush seal at the base, compression seals around the frame.
- 3.Old timber sash & casement windows — V-strip or brush-pile seals in the tracks.
- 4.Wall vents from removed gas heaters — cap permanently if the appliance is gone.
- 5.Downlights — replace with IC-rated LEDs or fit ceiling-side covers to seal the penetration.
- 6.Chimney & flue — inflatable chimney balloon or a permanent damper if unused.
- 7.Pipe & cable penetrations — expanding foam or acoustic sealant at wall/floor entries.
Signs your home leaks badly
- Curtains move when doors are closed
- Cold spots near skirting or under doors
- Whistling around window frames on windy days
- Heater running non-stop yet rooms feel cool
- Visible daylight around door or window seals
Don't seal these
- • Sub-floor vents (needed to prevent damp & rot)
- • Weep holes in brick veneer walls
- • Flues serving active gas appliances
- • Roof-space vents on tile roofs
- • Fresh-air intakes on ducted heating
Air-tightness targets (ACH50)
| Home type | Typical ACH50 | Target after sealing |
|---|---|---|
| Pre-1980 weatherboard | 15 – 30 | 7 – 10 |
| 1980s–2000s brick veneer | 10 – 20 | 5 – 8 |
| New build (NCC 2022) | 5 – 10 | 3 – 5 |
| Passive House certified | n/a | ≤ 0.6 |
ACH50 = air changes per hour at 50 Pa pressure. Measured with a blower-door test.
Find out where your home is leaking
A NatHERS existing-home assessment or blower-door test tells you exactly which draughts to seal for the biggest bill drop — before you spend on kits.