NatHERS Whole-of-Home Explained: The New Energy Budget for NSW Homes
Whole-of-Home scores the energy use of your fixed appliances against an annual budget. Here is how it works alongside your star rating.
Since NCC 2022, a NatHERS assessment in NSW has two parts. The first is the familiar star rating for the building shell. The second is Whole-of-Home, a newer measure that often confuses owners and even some builders. This guide clears it up.
The two halves of a modern assessment
Think of your home as a thermos and the things you plug into it. The star rating measures the thermos: how well the walls, roof, windows and insulation hold comfortable temperatures. Whole-of-Home measures what you run inside it: the hot water system, heating and cooling, lighting and any solar generation.
What Whole-of-Home actually scores
Your assessor models the fixed appliances and compares their annual energy use to a benchmark budget for a home of your type and location. You receive a Whole-of-Home score out of 100, where higher is better. To comply, the home must meet the minimum score for its climate zone.
| Counts toward Whole-of-Home | Does not count |
|---|---|
| Hot water system | Fridges and freezers |
| Heating and cooling | Televisions and computers |
| Fixed lighting | Portable appliances |
| Rooftop solar (as a credit) | Cooktops and ovens (plug-in) |
Why owners actually like it
Whole-of-Home rewards smart equipment choices. A heat-pump hot water unit, efficient air conditioning and a small solar system can lift the score significantly, which gives you room to move on other parts of the design. It turns compliance into a set of choices rather than a single pass-or-fail wall.
Designing to pass both tests
- Get the shell right first. A solid star rating reduces the heating and cooling load the appliances have to cover.
- Choose an efficient hot water system early. It is usually the biggest single lever.
- Consider even a modest solar array. The credit often pays for itself in compliance terms.
Frequently asked questions
Can a great Whole-of-Home score rescue a weak star rating? No. Both tests have minimums and both must be met. They complement each other rather than substitute.
Do I need solar to pass? Not always, but it is frequently the most cost-effective way to lift the score.
Want your shell and appliances modelled together for the best result? Talk to our assessors.
BASIX & NatHERS specialists, a division of Contrive Consultants. We help NSW homeowners and builders achieve energy-efficient, compliant homes.