NCC 2025: What Commercial Building Designers Need to Know

6/15/20263 min read

NCC 2025: What Commercial Building Designers Need to Know

The National Construction Code (NCC) 2025 introduces some of the most significant energy efficiency changes to commercial buildings since Section J was first established. While NCC 2022 focused heavily on residential housing, NCC 2025 shifts its attention towards reducing operational emissions from commercial buildings and supporting Australia's pathway to net zero.

Who Does NCC 2025 Apply To?

The new energy efficiency provisions primarily apply to non-residential buildings, including:

Class 3 buildings
Class 5 offices
Class 6 retail buildings
Class 7 storage buildings
Class 8 industrial buildings
Class 9 public buildings

Importantly, Class 2 apartments continue to follow the existing NCC 2022 provisions. Residential dwellings under Volume 2 also remain largely unchanged.

Key Energy Efficiency Changes

Mandatory Solar PV

One of the most significant updates is the introduction of mandatory rooftop solar PV requirements for many commercial buildings. Depending on the building type and available roof area, a substantial portion of the roof may need to be allocated to solar generation. This represents a major shift towards reducing grid energy consumption and operational emissions.

Under NCC 2025 DTS provisions, solar panels are mandatory. Whilst the current NCC 2022 (the existing code) only requires electrical provision for solar panels (not the panels themselves), NCC 2025 DTS will require solar panels for 100% of the roof all commercial buildings except where that’s not feasible (e.g. shaded roof, roof terrace etc.)

For some designs it may be possible to develop a J1V3 Performance Solution to reduce or remove the Solar Panel requirement. This will be challenging however, as the removal of the solar panel would need to be offset by other changes in the building design.

Improved Building Fabric Performance

NCC 2025 strengthens the thermal performance requirements for commercial building envelopes through:

Increased insulation requirements in many climate zones
Improved façade performance targets
Higher-performing glazing systems
More stringent roof performance requirements

These changes are intended to reduce heating and cooling demand and improve occupant comfort.

Vertical Shading Now Recognised Under DTS Pathway

A notable improvement in NCC 2025 is the increased recognition of vertical shading devices within Deemed-to-Satisfy (DTS) assessments.

Historically, external shading provisions largely focused on horizontal shading elements, which often limited design flexibility for east- and west-facing façades where solar gains are typically most significant. NCC 2025 expands the range of shading solutions that can be considered, allowing vertical fins and similar façade shading devices to contribute towards compliance.

This change provides architects and designers with greater flexibility to optimise façade performance while maintaining architectural intent. In many cases, appropriately designed vertical shading can reduce solar heat gains, improve occupant comfort and potentially reduce glazing performance requirements.

For projects with large areas of east- or west-facing glazing, incorporating external vertical shading early in the design process may provide a cost-effective pathway to compliance.

Enhanced Air Sealing Requirements

Building envelope sealing requirements have been expanded to reduce uncontrolled air leakage. Additional attention is now required for:

Roof lights
External doors and windows
Exhaust systems
Penetrations through the building envelope

Improved sealing helps reduce energy losses and supports more efficient HVAC operation.

Higher Efficiency Building Services

The NCC 2025 introduces stricter performance requirements for:

Air-conditioning systems
Ventilation systems
Fans and controls
Lighting controls

Demand-controlled ventilation and automated lighting controls are expected to become more common, helping reduce operational energy use.

Changes to J1V3 Performance Solutions

For projects pursuing a Performance Solution through J1V3, several important updates have been introduced:

Lower allowable energy consumption targets
New greenhouse gas emission limits
Mandatory solar PV assumptions within reference buildings
Additional thermal comfort and peak load assessment requirements
New 98th percentile heating and cooling load criteria

These changes make it more difficult to rely solely on efficient building services to achieve compliance. Greater emphasis is now placed on the performance of the building envelope itself.

What this means for project teams

The earlier energy efficiency requirements are considered during design, the easier and more cost-effective compliance becomes. Architects, builders and developers should consider:

Building orientation and glazing ratios early
Higher-performance glazing specifications
Improved insulation and air-tightness detailing
Rooftop solar PV integration
Electrification strategies and reduced reliance on gas systems

Projects that address these considerations during concept design will generally experience fewer compliance challenges later in the approval process.

Final Thoughts

NCC 2025 represents a major step towards lower-emission commercial buildings. With mandatory solar PV, tighter building envelopes, higher-performing services and stricter performance pathways, commercial projects will need a more integrated approach to energy efficiency than ever before.

For developers, architects and builders, understanding these changes early will be critical to achieving compliance while managing project costs and maintaining design flexibility.

NCC 2025: What Commercial Building Designers Need to Know