Building energy efficiency provisions

National Construction Code (NCC) 2019 building energy efficiency provisions will be introduced in the Northern Territory for non-residential buildings.

To date the building energy efficiency provisions in NCC Volume one Section J have not applied to non-residential buildings in the Northern Territory.

An NT variation will be included in NCC 2022 that for Class 3 and Class 5-9 buildings, from 1 October 2023 Section J of NCC 2019 applies.

In consultation with industry, the department will ensure information and education is available to building practitioners in the Territory in preparation for the changes required to comply with NCC 2019 Section J.

Background

A comprehensive cost benefit analysis was undertaken by energy efficiency specialists DeltaQ, that examined the impact of the potential adoption of either the energy efficiency provisions in the NCC 2016 or NCC 2019 from both private (owner-occupier) and social (NT economy-wide) perspectives.

The report on the cost benefit analysis has been finalised following industry feedback and was considered as part of the decision to adopt NCC Section J in the NT.

DeltaQ report

NCC 2019 requirements were found to be cost-effective from both the private (owner-occupier) and social (NT economy-wide) perspectives under all scenarios and assumptions examined. The analysis also concluded that NCC 2019 significantly outperforms NCC 2016 under all scenarios considered.  NCC 2022 Section J was not available at the time of the cost benefit analysis and therefore has not been considered in the data.

There was a small increase in the modelled cost of constructing buildings compliant to Section J of the NCC in Darwin and in Alice Springs and the additional cost of NCC 2019 compliant buildings was actually less than the additional cost of NCC 2016 compliant buildings.

Higher energy savings were modelled with the adoption of the 2019 version compared with the 2016 version. Comparison of the current construction examples (base case construction) to the Deemed-To-Satisfy (DTS) NCC 2019 Section J requirements found that the most significant change introduced by adoption is adding or increasing insulation for building envelop (walls, roofs and some floors) to counteract impacts of thermal bridging and high heat transfer across the building fabric from the exterior.

According to the modelling, building archetypes that are compliant with NCC 2019 cost 1.4%-2.4% ($57-$81 per m2) and 1.3%-1.7% ($42-$76 per m2) more than the base case in Darwin and Alice Springs, respectively.

Modelling showed that 13–40% energy savings could be realised if NCC 2019 is adopted.  NCC 2019 average energy savings of 23% across all building archetypes in Darwin, and 29% for Alice Springs.

The adoption of NCC 2019 was shown to generate a greenhouse gas savings of 891,000 tonnes of CO2 cumulative over the modelled period from financial year 2023 to financial year 2070. One tonne of CO2 looks like a 500m3 hot air balloon. Relative to the base case, the emissions savings associated with the adoption of NCC 2019 is 23.3%.

The analysis found that while cost effective to adopt Section J for a single-storey office building, this archetype was the most sensitive from a cost benefit perspective due to the high building envelope to floor area ratio.

For this reason, DeltaQ prepared case studies focussed on the single-storey office building archetype (in both Darwin and Alice Springs), showing how different designs can demonstrate NCC 2019 compliance using the DTS method and also a verification method.

For more information, view the report:

More information

Email: bas.policy@nt.gov.au
Telephone: 08 8999 8982


Last updated: 16 September 2022

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