Most first home buyers have never heard of it until it lands in a conversation with their builder, usually somewhere between choosing a floorplan and picking a colour palette. Understanding it early is one of the simplest ways to protect yourself from the pitfalls that catch other first home buyers out.

Somewhere behind every floorplan, there’s a set of calculations running quietly in the background, deciding how comfortable your new home will be to live in.

what does a 7-star rating measure?

At Forma Homes, we don’t just aim for 7-star because the code requires it. We build to it because it’s the difference between a home that costs a fortune to heat and cool, and one that just works.

To break it down simply, we sat down with Debbie Bute, Technical Manager at Leading Energy ESD and a NatHERS accredited assessor who works closely with our drafting team.

“Seven-star is the standard the NCC sets,” Debbie explains. “It’s about getting the thermal envelope of your home to a level where you’re comfortable, without needing high artificial heating and cooling loads.”

In other words, it’s a measure of how hard your home has to work – and how hard your air conditioner and heater have to work – to keep you comfortable through a Perth summer and winter.

the levers that get a home to 7-star

 A 7-star rating isn’t decided by one thing. It’s the combination of orientation, insulation, and glazing, all modelled together by government-regulated software built on a CSIRO-developed engine.

“It comes down to good orientation, a good glass-to-floor ratio, and making sure the glass sits in the right spots – mainly to capture winter sun, without letting rooms get too hot or too cold throughout the year,” says Debbie.

Some of those levers matter more than others. Wall and ceiling insulation help, but there’s a limit on how much difference they make once you’re already building to a solid base specification. Glazing tends to move the needle further – upgrading to low-E glass, or simply keeping window sizes proportional to the room, can be the difference between a design that passes easily and one that doesn’t.

why more glass changes the equation

 It’s a common misconception that a 7-star rating is a formality – something any reasonably built home will achieve without much thought.

“People think seven-star is a no-brainer,” says Debbie. “But it’s not just about throwing insulation in the walls or the ceiling. It’s the entire makeup of the design. If you want a lot of glass, you either need to think about your design early, or be prepared to pay for it.”

That’s the part that catches people out. A design with generous, floor-to-ceiling glass in the living areas might look stunning on paper, but it can push a home’s glass-to-floor ratio well beyond what the NCC allows for a standard 7-star pathway.

When that happens, there are really only two options: reduce the glass, or upgrade to more expensive glazing to compensate. Neither is a conversation anyone wants to have after they’ve already locked in their design and their finance.

getting it right before you’ve locked anything in

This is where the timing of the assessment matters as much as the assessment itself. Debbie and the Forma Homes team, have worked together for numerous years, which means our team already understands what tends to work and what doesn’t before a design ever reaches Debbie’s desk for formal assessment.

That doesn’t mean every site is straightforward. Block orientation, shading from retaining walls or fences, and how much natural winter sun a block receives all play into the outcome, and it’s not something a builder can control after the land has been chosen.

What Forma can control is when we run the numbers. Assessing a design for energy efficiency early means any changes are simple and inexpensive. Assessing it late means the only options left are the expensive ones.

When it comes to transparency, we lead by example, , and that means telling you about the trade-offs before they become a problem, not after.

why this matters if you’re building your first home

 Beyond ticking a compliance box, a genuinely 7-star home has practical upsides for a first home builder:

• Lower running costs. Nobody knows exactly where electricity prices are heading, but a well-insulated, well-orientated home needs less artificial heating and cooling to stay comfortable, whatever happens to the cost of power.
• A more comfortable home, year-round. Good passive design means fewer extremes – a home that doesn’t swing between too hot and too cold depending on the season.
• Solar as standard. Forma includes solar panels across our designs, which pairs naturally with a well-rated, lightweight steel-frame build and helps bring down running costs further. 

building confidence, not just compliance

 Because Debbie is an accredited assessor who is regularly audited by the NatHERS administrator, a Forma 7-star rating reflects what the software’s CSIRO-built engine calculates – not a best guess.

“I get audited,” Debbie says. “I could have a project randomly picked up and reviewed by the NatHERS administrator. If I score below 80, I have to explain every decision I made. Last time I was reviewed, I got 96 – so you know with Forma, your seven-star is seven-star.”

A 7-star rating won’t show up on a floorplan or in a photo of your new kitchen. But it’s quietly doing more for your day-to-day comfort, and your power bill, than almost anything else in the build.

That’s the whole idea behind partnering with an accredited expert like Debbie, and getting the numbers right early: fewer surprises, fewer compromises, and a home that’s genuinely built to perform, not just to pass.

With Forma, you don’t just end up with a home you love – you know how you got there, and why it works.