2026 NCC + state rebates
Energy Efficient Renovations in Australia — Ranked by $/Star
Renovating an existing home from 1–2 stars to 5–6 stars typically costs $15,000–$60,000 staged over 3–5 years. Start with the highest $/star upgrades below, stack the rebates, and cut bills $800–$2,000 a year.
6 upgrades ranked by $/star gained
Ceiling insulation R6.0+
$2,000–$4,500
Star gain: 1.0–1.5 stars
Single biggest $/star gain. Do first.
Draught sealing
$1,500–$3,500
Star gain: 0.5–1.0 stars
Weatherstripping, sealed exhausts, gasketed downlights.
Retrofit double glazing
$500–$1,200 per window
Star gain: 0.5–1.5 stars
Prioritise east/west windows first.
Heat-pump hot water
$2,500–$4,500 (net STCs)
Star gain: Cuts HW energy 65–75%
Federal STCs + state rebates stack.
Reverse-cycle split systems
$1,500–$3,500 per unit
Star gain: 0.5 stars + gas savings
Replace gas ducted; right-size per zone.
Underfloor insulation
$30–$60/m²
Star gain: 0.3–0.8 stars
Best in VIC/TAS/ACT climates.
Do I need council approval or a NatHERS assessment?
| Renovation type | Permit? | NatHERS/BASIX? |
|---|---|---|
| Cosmetic (paint, kitchen, bathroom) | Usually no | No |
| Insulation / draught / hot water swap | No | Optional (unlocks rebates) |
| Structural alteration < $50k (NSW) | Yes | May need BASIX |
| Extension / addition | Yes | Yes — 7-star for new work |
| Re-clad or roof replacement | Yes | Optional — best time to insulate |
Rebates you can stack in 2026
- NSW Home Energy Saver: up to $15,000 interest-free finance — how to apply
- VIC Energy Upgrades (VEU): heat pumps, insulation, draught sealing rebates
- Federal Cheaper Home Batteries: ~30% off battery installation — program overview
- QLD Battery Booster: up to $4,000 on home batteries
- WA Residential Battery Scheme: — 2026 updates
- Federal STCs: automatic discount on heat-pump hot water and solar
Get a pre-renovation plan from a certified assessor
A NatHERS assessor models your current home, prioritises the upgrades with the biggest star gain per dollar, and lines up the rebates. Most plans pay for themselves within one measure.