The decisions made during construction affect your power bills and comfort for as long as you own the home. The good news is that most of what makes a home efficient in Queensland isn't exotic technology. It's good design, the right insulation, and careful installation of the details nobody sees once the plasterboard goes on.
The rules: 7 stars is the minimum
Since NCC 2022, most new homes must achieve at least a 7-star NatHERS energy rating. That rating is worked out by an energy assessor using a computer model of your plans, before you build.
That's the important part. The model assumes the insulation is installed without gaps, the windows are the ones specified, and the building is reasonably airtight. Air sealing and insulation details are where homes actually hit or miss that rating once they're built. A perfect energy report means nothing if the batts are squashed, missing or falling out of the ceiling.
Start with climate and design
Most Queensland homes sit in NCC climate zones 1 to 3 (hot humid, warm humid and hot dry). Brisbane, the Gold Coast and the Sunshine Coast are zone 2. In these climates, the job is mainly keeping heat out and letting it escape, so design does most of the heavy lifting:
- Orientation. Put living areas to the north, where the sun is easiest to control, and limit large windows facing west.
- Eaves and shading. Good eaves and external shading stop summer sun before it hits the glass. That's far more effective than blinds inside.
- Light-coloured roof. A light roof absorbs less heat and keeps the roof space cooler.
- Cross-ventilation. Windows placed to catch prevailing breezes let the house flush out heat on summer evenings.
- Ceiling fans. Cheap to run and they make a room feel several degrees cooler.
- Slab thermal mass, shaded. A concrete slab can help even out temperatures, but only if it's shaded from summer sun. In zone 2, don't pay extra for heavy walls. See our thermal mass guide for more.
Insulation
The type and amount of insulation depends on your climate zone and design, and your NatHERS assessment sets the real numbers for your home. As a guide, the NCC deemed-to-satisfy option asks for about R2.8 total for external walls in zones 1 to 3, and roofs and ceilings typically land somewhere around R4 to R5 total, depending on roof colour and construction. Those are total system values, which include the roof, air gaps and linings, not just the batt.
Common options:
- Glasswool and polyester batts. The most common choice for walls and ceilings. They work well if they're fitted snugly with no gaps, not compressed, and kept clear of downlights unless the fittings are rated for it.
- Reflective foil and sarking. Very effective at blocking radiant heat from a hot roof in Queensland. Foil needs an air gap next to it to work.
- Blown-in loose fill. Useful in ceilings that are hard to reach. It needs to be installed to the right depth and can settle over time.
- Rigid boards and spray foam. Used in specific spots, such as under slabs or in tricky junctions. More expensive and not usually needed throughout a standard Queensland home.
Gaps matter more than you'd think. Even a small percentage of uninsulated ceiling area can noticeably cut the overall performance of the insulation.
Air sealing
Air leaks let hot, humid air in during summer and push your cooling bill up. The usual leak points in a new home are:
- Gaps around window and door frames.
- Plumbing and electrical penetrations through walls, ceilings and the slab.
- Ceiling access hatches, which are rarely sealed well.
- Downlights and exhaust fans that open straight into the roof space.
- Joints in the wall wrap, and where the wrap meets windows and doors.
- Gaps under external doors and between the bottom plate and the slab.
These are sealed with flexible sealants, tapes for wall wrap, weather seals on doors and windows, and sealed covers on downlights and hatches. Expanding foam can fill larger gaps, but it shouldn't be used around window frames unless the window manufacturer allows it.
Condensation: don't trap moisture
The old advice to put plastic sheeting behind walls is wrong for Queensland. In a hot, humid climate, the moist air is often outside, and an impermeable layer on the inside of the wall can trap condensation in the frame.
NCC 2022 tightened the condensation rules. Exhaust fans from bathrooms, laundries and kitchens must discharge to outside air, not into the roof space. Requirements for vapour-permeable wall wraps and roof space ventilation apply in the cooler climate zones (4 to 8 for wall wraps, 6 to 8 for roof spaces), but your designer should still specify the right membrane for your home under AS 4200.1. More on this in why your builder should do a condensation risk analysis.
Ventilation and cooling
A well-sealed home still needs fresh air. In Queensland that usually means:
- Exhaust fans in bathrooms, the laundry and over the cooktop, ducted outside.
- Operable windows placed for cross-ventilation.
- Efficient air conditioning, sized properly and zoned so you only cool the rooms you use. An efficient heat pump hot water system or solar hot water is worth considering too.
Mechanical heat or energy recovery ventilation systems are common in cold climates. They're less common in Queensland homes, but an energy recovery unit can make sense in a very airtight home or one that's air conditioned most of the year.
What to check on site
You don't need to be an expert to spot most problems. Check these at the right stages:
At frame stage:
- Wall wrap is continuous, lapped correctly and taped where required, especially around windows and doors.
- Window and door flashings are installed before cladding.
At rough-in (before plasterboard):
- Wall batts fill each cavity with no gaps, folds or squashed sections.
- Penetrations through the wrap and top plates are sealed.
- Exhaust fans are ducted to outside, not just into the roof space.
After plasterboard:
- Ceiling insulation covers the whole ceiling, including over the hatch, and is kept the right distance from downlights.
- The ceiling hatch has insulation fixed to it and seals when closed.
Our C7 Frame and C10 Rough In checklists walk you through these checks stage by stage.
C10 - Rough In Stage Inspection Checklist
$59.00 AUD
Last updated 28 Oct 2026 · Revision 3 · Free updates for life
Checklist Type: Minor
Form Factor: Fillable, print-ready PDF (A4, 27 pages)
When to use: Rough-in stage: after services are installed, before cladding and linings go on
An 84-point rough-in checklist. Check plumbing, electrical, gas, solar, air conditioning and data after every trade has finished, before the insulation and linings hide them.
The short version
Design for the climate first, then make sure the insulation and sealing actually match what the energy assessment assumed. Ask your builder to show you where the air barrier runs and how penetrations will be sealed, then check it yourself at frame and rough-in.
