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Part H6 applies to class 1 and class 10 buildings. Its functional statement is that a building must reduce the energy consumption and peak demand of key equipment, decrease greenhouse gas emissions from energy use, and improve occupant health by mitigating the impacts of extreme weather and energy blackouts. That last clause is worth reading twice: the Code is now explicitly concerned with whether a house stays habitable when the power goes out in a heatwave.

H6P1 handles the building fabric. Rather than a single star figure, it sets three separate limits — the total heating load and the total cooling load of habitable rooms and conditioned spaces, and the total thermal energy load — each of which must not exceed the corresponding limit in Specification 44. Splitting heating from cooling is what stops a design trading a brutal summer against a mild winter.

H6P2 handles the equipment. It requires the energy value of the building's domestic services not to exceed 70 per cent of a reference baseline constructed from specified efficient equipment, described in the provision as including three-star heat pumps, a five-star gas water heater and lighting at four watts per square metre, and it requires the services to have features that facilitate efficient use appropriate to the location, the usage and the energy source.

The ABCB describes two deemed-to-satisfy routes. The first is an energy rating using accredited software, where for houses the details sit in Clause 3 of Specification 42 in Volume Two and require a whole-of-home energy rating of at least 60 using a NatHERS software tool. The equivalent threshold for apartments is 50.

The second is the elemental provisions, described as a prescriptive approach to complying with the housing energy efficiency performance requirements. Instead of modelling the house, you meet a set of prescribed element requirements. It is simpler and it suits conventional designs; it gives you nothing back for a clever plan.

The practical difference is flexibility. The whole-of-home provisions, as the ABCB explains them, holistically consider the efficiency of fixed energy-using equipment such as heating and cooling, heated water, lighting and pool and spa pumps, together with on-site renewable generation such as rooftop solar. That means an unusual design can trade: a bigger window somewhere is paid for by better equipment or generation. A prescriptive path cannot do that. If your house is not conventional, model it.

Making Australian houses tighter and better insulated moved moisture from a nuisance to a design problem. The ABCB's overview of the NCC 2022 changes says improvements have been made to the condensation management provisions for residential buildings, specifically adding a mould index to the verification methods, updating the deemed-to-satisfy provisions for vapour permeance in external walls and roof materials, and enhancing ventilation requirements for certain spaces, building on provisions introduced in NCC 2019.

What that means in a design is that the wall build-up and the roof build-up have to be considered as assemblies that manage vapour, not just as layers that resist heat. The wrong membrane in the wrong position in the wrong climate zone traps moisture inside a wall that used to leak enough to dry itself.

It also means the wet rooms have to actually exhaust to outside, and the roof space has to be able to breathe. These are not expensive items. They are simply invisible, which is why they get value-engineered out of a job by people who do not know what they are for.

The National Construction Code is written nationally and adopted by each state and territory, which means the edition in force, the date it took effect and any local variations are jurisdictional questions. The Code itself carries state and territory appendices for exactly this reason. Before relying on any account of what the Code requires, confirm which edition your jurisdiction has adopted for your project.

Everything that happens downstream of the design is also state-based. Who assesses the documents and issues the building approval, what a building surveyor or certifier must see, who may lawfully prepare the plans, and what the designer may call the service are all set by state law. Queensland licences building design by class through the QBCC; Victoria regulates the words architectural services and architectural design through the Architects Act 1991.

So the right question to a building designer is never whether they know the Code. It is which state's adoption they are designing to, and which certifier they expect to assess it.