Table 3: Proposed changes to the energy efficiency DTS Provisions for commercial buildings
Schedule 1
Defined terms
- Updates to the NCC defined term ‘envelope’ to clarify where the term applies
- Includes a new defined term ‘Solar Reflectance Index’
- Includes a new defined term ‘Total Solar Reflectance’
J2D2 Energy efficiency
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- Updates to give effect to the proposals throughout the DTS Provisions
- Updates to clarify how the installation of insulation must be undertaken
- Updates toTotal R-Value requirement for a roof or ceiling
- Includes higher reflectance and new requirement for emittance of metal roof of a building with rooftop air conditioning equipment
- Requires thermal performance of wall-glazing constructions to be assessed for each story, including any mezzanine
- Requires more stringent solar admittance requirements for wall-glazing in all building classifications and climate zones
- Updates to wall-glazing, Maximum Total System U-Value and opaque wall Total R-Value
- Updates to provide more clarity on the application of the provisions
- Removes application requirements which are now proposed to be covered by J5D2
- Removes application requirements which are now proposed to be covered by J5D2
- Updates to clarify when an airlock or the like is required, with new exemptions for entrances that are moveable walls or required to be left open for safety
- Updates to exhaust fans requirements for when they need to be fitted with a sealing device
- Removes application requirements which are now proposed to be covered by J5D2
- Minor updates to when a self-closing damper is required for evaporative coolers
- Updates to the air-conditioning control requirements to restrict simultaneous heating and cooling and prevent poor design
- Updates to reduce the threshold to provide economy in some climate zones
- Updates to add temperature reset requirement for heated water and condenser water
- Expansion of requirement for interlock to prevent air-conditioning from operating when an external door is opened
- Updates to the time-switch provisions to improve functionality and align with provisions for time-switches used to control lighting
- Updates to require energy reclaim systems to be fitted with a bypass where beneficial
- Reduces threshold to provide outside air treatment in some climate zones
- Includes separate provisions for outside air treatment for variable and constant outside air flow systems
- Includes a requirement for indirect evaporative cooling for larger, constant outside air ventilation systems in climate zone 1 and 3
- Removes variable speed fan requirements. Refer to J6D5 for related changes
- Updates to the time-switch provisions to improve functionality and align with the provisions for time-switches used to control lighting
- Updates to the provisions to align with EU327
- Updates to require peak efficiency and duty point efficiency to both be considered
- Updates to allow the efficiency at duty point to be assessed individually or collectively
- Includes a requirement for most fans to be capable of variable speed operation where the input power is above 750W
- Updates to require fans serving multiple rooms or spaces to be capable of variable pressure operation, to the extent practicable
- Addition of pressure drop allowance for exhaust louvres and relief louvres
- Refer also to changes to Specification 46
- Removes the exemption for equipment complying with MEPS
- Updates to broaden the use of variable volume systems and to facilitate more effective turn down of systems
- Updates to clarify the exemption for pipework insulation within equipment covered by MEPS
- Includes provisions to facilitate future electrification, including reserved electrical infrastructure capacity, plant space, and hot water distribution system temperatures that are appropriate to be delivered by heat pumps
- Updates to reduce wasteful operation of heating and cooling equipment serving outdoor areas
- Updates to specify minimum efficiency requirements for air-source heat pump equipment
- Updates to the minimum gross thermal efficiency requirement to 90% for gas heaters in all cases
- Updates increase the stringency of requirements for chillers and require chiller plant to be assessed based on the load served rather than chiller capacity. Provisions are specific to the climate, load and building classification
- Refer also to changes to Specification 47
- Updates to increase minimum efficiency requirements for air-cooled packaged air-conditioning systems and facilitate more efficient operation across the full load range
- Updates to test standards
- Updates to allow equipment in a building to be assessed collectively
- Refer also to changes to Specification 48
- Updates to require fans in heat rejection equipment to be capable of variable speed operation, except for heat rejection fans in chillers, unitary air-conditioning equipment and heat pumps that are covered by other aspects of Section J
- Updates to light switching and control provisions to make them easier to understand
- Updates to simplify control requirements and make them less prescriptive
- Refer also to changes to Specification 40
- Minor editorial updates
J8D2 (New)
Heater water supply and swimming pool and spa pool plant - application
- Includes a new exemption stating the J8 provisions do not apply to a sole-occupancy unit of a Class 2 building, or a Class 4 part of a building
- Updates to clause numbering
- Updates to facilitate future electrification, including reserved electrical infrastructure capacity, plant space
- Includes insulation requirements for pipework containing circulating heated water used for sanitary purposes and food preparation
- Updates to clause numbering
- Includes provisions to facilitate future electrification, including reserved electrical infrastructure capacity, plant space, and hot water distribution system temperatures that are appropriate to be delivered by heat pumps
- Update to the minimum gross thermal efficiency requirement to 90% for gas heaters in all cases
- Updates to clause numbering
- Includes provisions to facilitate future electrification, including reserved electrical infrastructure capacity, plant space, and hot water distribution system temperatures that are appropriate to be delivered by heat pumps
- Updates to the minimum gross thermal efficiency requirement to 90% for gas heaters in all cases
- Updates to allow bus ducts to be used with EV charging equipment
- Includes a requirement to specify the maximum permitted length of the cable run from EV charging distribution board or bus duct to car parking spaces
- Includes requirements for EV chargers for a specified number of spaces in carparking areas associated with a Class 3, 5, 6, 7b, 8 and 9 buildings
- Updates to the infrastructure requirements for future EV charging in recognition that these provisions are additional to the requirement to install EV charging equipment
- Updates require on-site PV panels to be installed. Capacity depends on the available roof space, climate zone and building classification. Additional PV is specified where gas is used to balance the emissions from gas appliances
Specification 33
Additional requirements
- Includes requirements to facilitate future electrification
- Includes requirements to specify a building using J1V1 must comply with the requirement for facilities for solar PV panels (J9D5)
Specification 34
Modelling requirements for J1V3
- Updates to require a reference building to be equipped with PV (J9D5)
- Includes the requirements for calculating U-Value and solar admittance of wall glazing
- Updates to require the use of future climate data
Specification 35
Modelling profiles for J1V3
- Updates to lighting operating profiles with reduced operation during unoccupied periods or low-occupancy periods
- Updates to occupancy schedules for Class 6 and Class 9c buildings to reflect higher daytime occupancy than other commercial buildings
- Updates to the HVAC operating schedule for Class 9c aged-care buildings
Specification 37
Calculation of U-Value and solar admittance
- Updates require Total System U-Value and solar admittance to be calculated on a single storey basis, thus limiting trade off between storeys
- Removes solar admittance limit from S37, refer to J4D6 for relevant provisions
- Updates to the shading multiplier methodology to expand it to accommodate vertical shading fins
- Includes the requirements to accommodate vertical shading
Specification 40
Lighting and power control devices
- Updates to refine and consolidate the lighting control devices to clarify their intended function
Note to Table 3: Table 3 presents the key proposed changes to the DTS Provisions of Section J for the next edition of the NCC. For a comprehensive view of all proposed changes, please see the NCC 2025 Volume One PCD.
