The 7-Star Pre-Build Checklist: 12 Things to Lock In Early

Reaching the 7-star NatHERS standard under NCC 2022 is far easier and cheaper when you make the right calls at the design stage rather than after the slab is poured. This checklist walks through the dozen decisions that have the biggest effect on your thermal performance score, and shows you how to sequence them so each choice supports the next.

Why early decisions matter most

NatHERS modelling rewards a home that works with its climate. Most of the variables that drive your star rating – where windows face, how wide your eaves are, how much insulation sits in the walls and roof – are baked in before a single brick is laid. Once construction is underway, changing them is expensive. Lock them in now and you avoid costly redesigns and last-minute glazing upgrades.

There is also a knock-on benefit. A home that performs well on the thermal shell needs smaller heating and cooling equipment, which trims your Whole-of-Home energy budget and your upfront fit-out costs. Good fabric decisions made at the drawing stage pay you back twice: once on the certificate and again on every power bill for the life of the home.

The 12-point checklist

1. Orientation. Aim to place living areas and their main glazing toward the north so they collect low winter sun and can be shaded in summer. Even a modest rotation of the floor plan can lift your rating.
2. Glazing specification. Decide early whether you need standard double glazing, low-e coatings or thermally broken frames. The right glass on the right wall does a lot of the heavy lifting.
3. Glazing area and placement. Generous north glass is an asset; large unshaded west glass is usually a liability. Balance the window-to-wall ratio on each elevation.
4. Eaves and external shading. Correctly sized eaves block high summer sun while letting winter sun in. Pergolas, awnings and screens help where eaves alone are not enough.
5. Wall and roof insulation. Set your target R-values for ceilings, walls and any exposed floors. Continuous, well-installed insulation beats a high number on paper that is full of gaps.
6. Draught sealing. Plan for sealed perimeters around doors, windows, exhaust fans and service penetrations. Air leakage quietly undermines an otherwise efficient home.
7. Roof colour and absorptance. In warmer NSW zones a lighter roof reflects heat and helps the rating; in cold zones a darker roof can be a small advantage. Choose with your climate in mind.
8. Thermal zoning. Group rooms by how they are used and separate them with doors so you only heat or cool the spaces you occupy.
9. Ceiling fans. Including fans in living areas and bedrooms can improve summer comfort and is recognised in the modelling.
10. Hot water system. An efficient heat-pump or solar hot water choice supports both your thermal outcome and the Whole-of-Home assessment.
11. Floor construction. Slab-on-ground, suspended timber or a mix each behave differently. Decide early so insulation and edge details can be specified.
12. Buildability of the detail. Make sure your insulation and sealing details can actually be installed on site. A clever detail that the trades cannot build will not perform.

A worked example: a single-storey home on a north-facing block

Picture a four-bedroom single-storey home on a block where the rear garden faces north. The first move costs nothing: place the open-plan kitchen, living and dining at the rear so the main glazing collects winter sun, and put the bedrooms and wet areas along the southern side where they need less daylight. With living areas to the north, a 600 to 750 millimetre eave over that glass shades the high summer sun while still admitting the lower winter sun.

Next, the glazing is tuned by elevation. The north windows can be generous because they are easy to shade and useful in winter. The west-facing laundry window is kept small, or given an external screen, because late-afternoon western sun is the hardest to control. Only after orientation, shading and zoning are settled does the assessor test whether the ceiling and wall insulation already specified are enough, or whether a step up in glazing performance on one or two elevations closes the final gap to 7 stars. In many cases the free moves do most of the work, and the paid upgrades are modest and targeted.

How the big levers compare

Common mistakes that cost stars

• Treating glazing as a single decision. The same window that helps on the north can hurt on the west. Glass should be specified elevation by elevation, not as one blanket product.
• Insulating to a number, not to a result. A nominal R-value means little if batts are compressed, gapped around downlights, or missing over the top plates. Continuity matters more than the figure on the data sheet.
• Forgetting the doors that make zoning work. Open-plan layouts feel generous but make it impossible to close off unused spaces. A single door between living and sleeping zones lets the household heat and cool only what it occupies.
• Leaving shading to the landscape. Trees take years to grow and may be removed by a future owner. Built shading – eaves, pergolas and fixed screens – is reliable from day one.
• Specifying details the trades cannot build. An elegant sealing junction that no one on site knows how to install will leak. Detail for the crew you actually have.

Where the savings come from

The cheapest path to 7 stars usually starts with the free or near-free moves: orientation, zoning and shading. These cost little but pay off across the life of the home. Spend on glazing and insulation upgrades only where the modelling shows they earn their keep. Our team can run the numbers for your specific plan so you are not paying for performance you do not need. You can see how we approach this on our services page.

Bringing the assessor in early

The single most useful thing you can do is get a NatHERS assessment underway while the plans are still flexible. Early modelling shows which of these 12 items move the needle for your block and climate, so your architect or draftsperson can adjust before the design is locked. It is far cheaper to nudge a window than to retrofit one. An early run also lets you compare two or three layout options side by side and choose the one that reaches the target with the least added cost.

Frequently asked questions

Do I have to do all 12 things to reach 7 stars? No. Most homes reach the target through a combination of a few strong moves rather than every item at once. The right mix depends on your block, climate zone and budget.

Is it too late to improve my rating once plans are drawn? Not necessarily, but your options narrow as the design firms up. Earlier is always cheaper and gives you more levers to pull.

Does a lighter roof always help? Usually in warmer NSW zones, but in cold climates a darker roof can be a slight benefit. It depends on where you are building.

Building or renovating in NSW? Get a fast, fixed-fee quote from our HERA-registered assessors.