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Section J Changes - Are you Prepared?

May 13, 2020

The National Construction Code (NCC) 2019 included sweeping changes across the code and none more so than for the energy efficiency provisions in Volume One Section J, with significant stringency increases included in the new edition.

The changes to Section J include:

  • Revised Section J Performance Requirement JP1 and removal of JP3
  • New Verification Method compliance options include GreenStar and NABERS
  • Substantially revised Section J DTS Provisions
  • New requirements for assessing split heating and cooling load assessments for apartments (the approach of 5 star minimum for any one apartments fabric performance but overall average of 6 stars across the apartments still applies)
  • Revised methodology for assessing combined facades including windows and cladding
  • New usage patterns for determining energy usage
  • Spandrel panels assessment
  • Thermal bridging requirements
  • Restrictions on certain roof colours
  • Substantially increases for heating and air-conditioning systems; and
  • New introduction of new façade calculator to replace the old glazing calculator.

Given the scope of the changes and to enable industry to transition to these new provisions, the ABCB provided an additional 12 month transition period from the adoption of these provisions. This transition period will expire on 30 April and the new provisions will take effect in most states from 1 May 2020.

Changes in more detail:

The changes to Section J arise from work the ABCB were asked to undertake in response to the COAG National Energy Productivity Plan, which aimed to reduce greenhouse gas emissions and improve energy productivity by 40% by 2030.

Resulting from this there are sweeping changes

  • Residential buildings (Class 1, 2 and 4) – Introduced NatHERS heating and cooling load limits (on top of existing minimum star rating).
  • Commercial buildings (Class 2 common area, 3, 5, 6, 7, 8 & 9) – Increased compliance provision requirements and added new verification methodologies, primarily included:
    • Changed energy consumption to greenhouse gas emissions – Increase weighting on renewable energy sources, i.e. Solar PV and onsite heat reclaimed systems
    • Introduced NABERS and Green Star verification as additional compliance pathways for Green Star & NABERS projects
    • Introduced Building Envelope Sealing verification pathway and changes to prescriptive Part J3 provisions
    • Revised methodology for assessing combined facades including windows and cladding
    • Implemented occupancy comfort assessment clause – Required thermal comfort modelling to assess PMV level

NCC 2016 vs NCC 2019

Part J1 – Building Fabric Changes

  • Under NCC 2016 you would follow prescriptive R-value requirement for all fabric elements.
  • Under NCC 2019 for non-façade elements, you follow prescriptive R-Value requirements (and relevant Specifications) for roof, ceiling, roof lights and floor framing.
  • Under NCC 2019 for façade elements new calculation methodology to determine wall glazing & cladding/external wall performance as part of combined performance.
  • Roofs will need to have solar absorptance of the upper surface of a roof must be not more than 0.45.
  • Part J2 Glazing has been removed in NCC 2019 taking account of combined window/glazing and wall assessment.

Potential impacts:

  • Thicker building fabric insulation
  • Higher performance glazing systems
  • Allow glazing performance offset through DTS without need for use of JV3
  • Low ratio glazing walls benefits
  • Issues for spandrel glazing walls
  • More complex modelling
  • Restriction on use of dark roof colours
  • More complicated design and compliance path requiring greater integration between designers, assessors, cladding and window suppliers.
  • Locks in at early stage commitment to wall and window types
  • Need for suppliers to update product data, testing and technical literature

Part J5 Air-conditioning & ventilation systems, Part J6 artificial lighting and power, Part J7 Heated water supply and swimming pool and plant and Part J8 Facilities for energy modelling have all had a number of changes and stringency increases effecting efficiency, the type of system used and the energy source.

More Information:

The ABCB have produced a range of new resources, YouTube videos, handbooks and new calculators to assist industry in applying the new provisions, and if you are supplying or specifying products, designing, building or approving commercial buildings then you are encouraged to review and familiarise yourself with these resources.

HIA has also recently ran a Section J webinar breaking down the changes and that can be accessed here

If you would like to discuss any of this information further contact HIA Building Services team on 1300 650 620 or email

REF: BCA 20-29