Powerhaus Director, Andrew Pickard, attended the ACT Certifiers Workshop on March 8th 2024, hosted by the ACT Government building reform team to discuss how recent changes to energy efficiency standards are handled. Here, we summarise the key insights and common queries from the workshop to help bring clarity and consistency to what is a complex legislative puzzle.
Summary of ACT energy efficiency legislation changes
New buildings
- NatHERS ratings must now reach a minimum of 7 stars for new single residences and required average for multi-unit developments
- NatHERS Certificates – both coloured and uncoloured NatHERS certificates are acceptable, provided the licensee holds a current ACT Energy Assessor license. Examples are detailed in the NatHERS Certificate Guide.
- Whole-of-Home (WoH) assessments have been introduced (see the National Construction Code (NCC) 2022 Part H6P2). There are two pathways for Whole-of-Home:
- Integrated into NatHERS assessments or,
- Conducted separately using the ABCB Whole Home Calculator, accessible here. This tool is open for use by anyone and does not need accreditation as an assessor.
Alterations and Additions:
- Unfortunately, alterations and additions new requirements now require NatHERS ratings of minimum 7 stars and modelling to encompass the entire house.
- Whole of home (WoH – H6P2) assessments not required for alterations and additions.
- As above, coloured and non-coloured NatHERs certificates acceptable.
- A Class A license is required for an ACT assessor working on an ACT alteration and addition.
Challenges have arisen in implementing new legislation for alterations and additions, both in applying the legislation accurately and in the difficulty for homeowners to comply. We’re in conversation with the ACT government and building certifiers around creating interpretation and application. There is industry concern that these changes may result in increased knock down rebuilds, and block homeowners from small, smart additions and improvements.
New compliance pathways under NCC 2022
- There are multiple pathways to compliance under the NCC 2022 including:
- Deemed-to-Satisfy (DTS) using Elemental Provisions (also known as the Glazing Calculator),
- Verification Using Reference Building (VURB),
- NatHERS 7 Star, and
- the new Performance Solution.
We’re prioritising the use of NatHERS for new homes and are transitioning to Performance Solutions where applicable–more on that below.
Addressing concerns regarding alterations and additions
The majority of the meeting concerned how to treat Alterations and Additions; Powerhaus Engineering have heard concerns from many certifiers on this topic.
1. Prevailing concern that the 7-star requirement for alterations and additions is unrealistic, expensive and prevents sensible home improvements
There’s concern that the stringent 7-star requirement for alterations and additions may set an unrealistic benchmark, potentially resulting in increasing or unrealistic renovation costs and the demolition of homes rather than their improvement. Powerhaus empathises with these concerns and has dedicated substantial resources to find the most sensible compliance pathway; we see a Performance Solution as the most useful pathway here.
Alterations and additions are posing significant complexities to the legislation; what were initially perceived as isolated edge cases have proven to be commonplace scenarios.
2. Whole-of-home removed for existing homes
Powerhaus has raised several concerns regarding the application of Whole-of-Home (or H6P2) to alterations and additions. Fortunately, these requirements have been removed – alterations and additions in the ACT do not need to demonstrate compliance with NCC 2022 H6P2.
3. Uncertainties, concessions, and grey areas persist
During the workshop, it was acknowledged that uncertainties persist regarding the application of legislation, designed for new homes, to alterations and additions. The complexity of the accompanying legislation, including the ACT appendix for the NCC 2022 and concession documentation, adds to the challenges faced by certifiers in making accurate determinations.
Discussions also revolved around concessions for existing elements of dwellings lacking insulation underneath. It’s anticipated that the building reform team will review this aspect, potentially offering additional concessions for existing homes built on slabs.
Numerous uncertainties persist regarding assumptions when modelling homes under the legislation. Powerhaus eagerly anticipates further communication with the building reform team to unpack these issues and will continue to provide feedback to improve implementation of this legislation.
Understanding the new Performance Solution pathway
New to the NCC 2022, Performance Solutions offer a more flexible pathway to show compliance with the Code. Requirements for a Performance Solution are set-out in the NCC 2022 Part A2G2.
Both NatHERS 7-Stars and “DTS” or Elemental Provisions are deemed-to-satisfy pathways, whereas the Performance Solution demonstrates compliance with the Performance Requirements.
The energy efficiency Performance Requirements are clear heating, cooling, and total energy use limits, set out in Part H6.
Performance Solutions offer enhanced flexibility in thermal modelling inclusions. This flexibility is particularly valuable for homes in cooler climate regions such as the ACT and Climate Zone 7, where building details like air tightness can play a significant role.
A comprehensive analysis of climate zones is required for determining key characteristics, which, along with the floor area of the house, determine the loads the homes must meet to comply. Any Performance Solution should explicitly outline the code, determined limits, and assumptions behind the modelling. It’s worth noting that this pathway is intricate and necessitates a deep understanding of building physics, climate data, and legislation. We stand by the Performance Solution we’ve developed and have actively sought feedback from certifiers and legislators through testing on multiple projects.
Final thoughts
We welcome the ACT Government’s proactive engagement with certifiers and are grateful for the opportunity to contribute, especially amidst the current lack of engagement with energy assessors.
Increasing energy efficiency of our homes is important for health, energy use and climate response – however it is important to balance these requirements for existing homes, so that easy, clear and sensible pathways exist for homeowners to maintain and improve their existing homes.
