The Study

The Study provides energy efficiency consulting services, architectural drafting and various other consulting services to the architectural and construction industry

NCC 2022 Energy Efficiency Changes - Residential

May 2025 will see the end of transition periods for NCC2019, and projects submitted for permits will need to meet the increased requirements of NCC 2022.


NatHERS

Steel thermal bridging requirements have been implemented – steel framing will be de-rated in the software to simulate the impact of the thermal bridging in steel.

Restricted roof space – where rafters sit on a wall plate, ceiling insulation will be de-rated as it is assumed the insulation will be compressed. It may be worth raising plate height above ceiling height, or if you use trusses, allowing for a heel, to allow full depth insulation to all ceiling areas.
Downlights are now required to be modelled if they are not shown – so please ensure electrical plans are supplied, as the assumptions will now be that downlights are included, impacting the default ratings
As you’ve likely seen over the last year or two – getting more information to me can often help the rating, it really does make a difference to nominate roof colours, window frame colours, floor coverings

Please also be aware that a new code-of-conduct applies for NCC22, and any information used in the assessment will need to be shown on the drawing set. To date, I have included a lot of information in the energy certification – roof colour, window manufacturer etc. Drawings which note “insulation to energy assessors report” were also accepted

Under the new code of conduct – all the information in the assessment needs to be on the drawing set – so please allow for additional time at certification as I may feed you back with information to include, and this will need to be added to the drawings to allow release of certificates.


Elemental

Stringency has been increased, to better align with elemental being equivalent to seven stars. There are now also a lot of “not permitted” outcomes in the provisions.

Dark colours have been restricted in the warm/temperate climates, similar to the commercial provisions. Monument is not a permitted colour in Perth and the South West, light/mid colours are required.
Steel thermal bridging requirements have increase, the R0.2 thermal break alone won’t comply  – with additional provisions required to offset the thermal bridging in steel framing.

 Some major snags to be mindful of under this method

  • Wall height limit – 3600h. Averaging is permitted for heights, so if there is a small area over this, it would be acceptable.

  • Shading limits – max 1500 deep eaves/verandah. Averaging not permitted – therefore any project with an alfresco, porch or deep verandahs are not permitted under this method.

  • Suspended, unenclosed floors – not permitted in zones 4 & 5. This means an upper storey which overhangs open air is not permitted under this method.

  • Under slab insulation requirements apply for climate zone 6

  • Removal of masonry concession for Class 10a parts in zone 5. Under NCC19, garages could be separated by single masonry construction. NCC22 requires the garage either be separated by, or enclosed by, walls meeting existing requirements. Therefore, insulated cavity masonry is needed between garage and house, or around external of garage (and garage roof/floor to meet code)


Whole of Home

I haven’t found the whole-of-home requirements to be too stringent in Perth and the South West areas. In the cooler zones it is slightly more difficult. I recommend talking with owners about getting off gas, heat pump hot water, induction cooking and Reverse cycle air conditioning. Projects with a wood heater seem to be OK. Pools typically trigger a requirement for solar PV. I am generally finding that using generic systems is acceptable – but please note that if WoH does become an issue on your project, I may need specific information on the systems, brand and model details for AC, hot water, pool pumps, details on any other heating (in slab/wood fire) etc.


Condensation

While not part of the energy provisions, sarking/membranes are often used for improving thermal performance – please be aware of the vapour permeability and drained cavity requirements in HP10.8 – in climate zone 6 I understand this means reflective sarkings cannot be used (there are no products available which are both reflective and meet the vapour permeance requirements) 


Studio/Outbuildings

One major issue exists with NCC22 – and that is that a Class 1 building without a kitchen or bedroom (ie, not a dwelling/ancillary – but a gym or pool room etc) cannot be assessed under the provided methods
NatHERS can only be used for a whole dwelling, so is not permitted to be used for these building types.
The elemental method cannot be used if the project hits one of snags noted above – ie deep shading/alfresco, walls higher than permitted, suspended unenclosed floor, dark roof.

These projects cannot be assessed using accepted methods, and will need to be handled on a case by case basis, likely with performance solutions.

The ABCB is aware of this issue, and there could be a practice note or update in the ABCB handbook coming – but for now, their approach is it will be rectified in future versions of the NCC.


Alterations & Additions

The WA Alts/adds protocol has not been updated by Building & Energy / DEMIRS. My discussions with them basically confirm that the principles can be applied

I have created an updated protocol calculator to output the sliding scale of performance for glazing, similar in approach to the NCC19 provision, but note the NCC22 is more stringent, so getting compliance will be more onerous than NCC19
As noted above – the calculator now needs more data – room usage, floor finish, opening style & frame colour
To date, I have often worked on the elemental pathway for alts/adds work – but given the changes to the elemental requirements, it is likely that more projects will require NatHERS modelling

If you do not have good quality existing drawings from the council or owners, please be aware that a detailed site measure and existing drawings will likely be needed. To create a NatHERS model, I need a lot of information on the existing building, often this information is not shown on existing drawings – please make owners aware that there may need to be additional work for you to create detailed existing record drawings.

 

It is not clear how whole-of-home will be applied to alterations and additions, and projects such as a proposed pool (and no building work). I would expect to apply the approach of the protocol – if the works do not change existing services, no requirements apply. New works with new services will need to meet code – and more involved alts/adds can apply a sliding scale based on area of existing vs new and see if we can work out a target which meets the intent of the provisions.

The more info I have, the better – so when conducting site visits, please take photographs of existing stoves, ovens, hot water units and AC compressors – including any model information or specification plates if possible.


NCC2022 does mean a higher level of stringency for energy compliance, but also a higher level of documentation and decision making early in the process. Unfortunately, leaving items for the client and/or builder to select may no longer be an option, decisions will need to be made earlier in the project.

Impact of NCC2022

NCC2022 is still a long way from becoming mandatory in WA - but we have started to look at the impact of shifting to seven star minimums, and the introduction (in WA) of heating and cooling load limits.

Many are aware that when transition periods end, dwellings will need to achieve seven stars in NatHERS software, up from the current six star rating - but did you know that the "stars" under NCC19 and NCC22 will be different? There are different weather files, adjusted star bands and different rules for how assessors must model.

We have had a look at the impact of these changes for ten houses across nine climate zones and two NCC versions - a total of 180 simulations run. Have a look at our facebook page to see the results for each climate zone we tested
https://www.facebook.com/the.study.australia

NCC 2019 Energy Efficiency Changes

 NCC 2019 has brought increased stringency requirements to the energy efficiency provisions. Due to the impact of these changes, the energy efficiency provisions are subject to a 12-month transition period. Projects which may be submitted for building permits after 1 May 2020 should consider meeting the NCC 2019 energy provisions to ensure there are no issues with obtaining building permits after that time. 

The Study will start to include advice for compliance with NCC 2019 so that you can start to see how these changes may impact your projects from 1 May 2020.


 Residential Impacts for Energy Efficiency – NCC 2019

 The 2019 update of the NCC brings some changes to the energy efficiency requirements for residential buildings. The reference building method is seeing a major overhaul, there is a new verification method being introduced for building sealing and heating and cooling limits are being introduced. While not considered an increase in stringency by the ABCB, these changes will have a major impact from 1 May 2020: 

Verification using a reference building (VURB) method 

The ABCB are introducing a raft of additional parameters for modelling of the reference building, and effectively this method will not provide a less stringent compliance pathway than NatHERS (star ratings) in most circumstances. This will effectively spell the end of the VURB method as a viable option for compliance. 

The changes proposed affect the modelling of the reference building, which will now need to be modelled with low ceilings, insulated masonry veneer walls and no glazing size/location changes - in a thermal simulation software separate to NatHERS software. This has been tested to result in an improvement in the performance for the reference building where the reference building often rates over six stars – this means that the least stringent method for compliance will become the NatHERS (star rating) method.  

As the reference method will need to be a separate model to the NatHERS model – the additional time and cost of testing this method only to find that it is more stringent than NatHERS will effectively spell the death of the VURB method of compliance.

 Building Sealing 

There is a new verification method being introduced for building sealing – being a blower door test to achieve less than ~10 air changes per hour. This is not a particularly stringent requirement, and this test is not mandatory.  

We believe that the blower door testing is only being introduced at this stage and will likely become more stringent and compulsory in further revisions of the NCC. The deemed-to-comply provisions remain largely unchanged, with the addition of a requirement to weather seal any doors connecting a garage and residence.

Heating & Cooling Limits 

For NatHERS (star rating) method assessments, in addition to requiring a minimum six star rating, there will also be heating and cooling load limits introduced. Currently, a six star rating could have very high heating loads, offset by very low cooling loads (or vice-versa). The load limits are aimed to target the worst performing 10% of dwellings with disproportionate heating or cooling, and will require some modification of the design or spec to bring the performance into a more balanced heating and cooling loading. 

This requirement should only impact on a small proportion of projects but may result in some design amendments or improved insulation spec to achieve compliance.  


 Commercial Impacts for Energy Efficiency – NCC 2019

 NCC 2019 will bring sweeping changes to the Section J provisions. Section J was last updated in 2010, with the last major overhaul in 2006. This 2019 revision sees some significant changes, estimated to result in a ~40% energy usage reduction across commercial buildings. 

Verification methods 

Where verification using a reference building (JV3) has long been a part of Section J – new verification methods including NABERS energy and Green Star are being introduced. 

The Study is considering training in NABERS and Green Star to provide further options for compliance, particularly in light of the deemed-to-comply changes.

 Roofs 

Dark coloured roofs will no longer be permitted under DTC provisions – commercial buildings will need a light coloured roof (SA Max. 0.45) to comply under this method. There has been a small performance increase for light roofs in Climate zone 5. 

Please note the solar absorptance requirements will now mean any roofs assessed under DTS will need to be Whitehaven, Surfmist, Classic Cream, Paperbark, Shale Grey or Evening Haze. All other colorbond colours, zincalume or tiles will need to use another compliance method. We are not yet sure how this will impact on alts/adds where added roof areas are proposed to match existing.

Walls / Facades 

Currently, walls and glazing are assessed independently – NCC 2019 groups both wall and glazing performance together into façade performance. Glazing has been assessed against a base case of 5% window size to provide minimum natural light with a basic window – and any increase in proportion of the window will require a relative increase in performance in the façade (wall and window combined). The stringency increase means that 63% of buildings tested against current requirements in climate zone 5 would not be compliant under NCC 2019 – so roughly two thirds of the projects will require changes to improve performance to match the top 1/3 of projects – this is a very marked increase in stringency. 

We expect full glazed facades to no longer be possible under DTS provisions, even for showroom/retail type uses. Heavily glazing facades will need to allow for very high-performance glazing systems and/or high performing wall systems. The benefit/cost ratios estimate that a wall with 45% window to wall ratio will cost up to 25% more under NCC 2019 than current requirements in climate zone 5.

 Floors 

Floor performance is now based on a ratio of floor area to perimeter calculations, and the inherit R-Value of a floor will be impacted by the wall thickness.

 The NCC does not have much information on how this method is calculated yet – but from our understanding it appears that slab on ground construction will require some additional insulation in most circumstances.

 Mechanical / Air Conditioning 

There are changes across the mechanical sections, which now include fans and pumps. Stringency is increased across all parts, including economy cycles and outside air requirements. Lifts are now also brought into Section J and have minimum energy efficiency requirements. 

Lighting 

The current regulations were written around the use of fluorescent lighting, but NCC2019 will be updated to reflect LED lighting technology. The result is that allowable lighting is being reduced to reflect the lower wattages of these lights – i.e. retail will be reduced from 22W to 14W/m² and office spaces from 9W to 4.5W/m²


 NatHERS (Star Rating) Scheme updates

Chenath – the simulation engine which runs behind all three NatHERS software options is also having a major updated released. There will be new modelling parameters for glazed corridors & basement carparking zones (Class 2 / apartments) and double height void spaces. There are also improvements to slab edge insulation modelling (currently not able to be included) and some additional materials being added to the library. 

The impact of these changes remains to be seen – hopefully these updates result in more accurate simulation. There is no mention of fixing long-standing issues such as the out of date and irrelevant window library, nor climate zoning issues in the South West.

 Alterations/Additions reminder 

Please remember that alts/adds are generally required to be assessed as a whole – we need details of the existing windows/glazing and shading as a minimum. If the project is not compliant under the elemental method and we need to move to thermal modelling options – more information on the existing building may be needed.  

Please ensure you are measuring existing windows, eaves/shading and taking lots of photos at alts/adds projects to enable us to assess the glazing accurately.

 So there are some pretty significant changes to energy compliance over the next twelve months, please let us know if you have any queries or concerns. Please continue to send projects or queries as early in the project as possible so that any items of concern can be addressed as early as possible. Changes become increasingly difficult and expensive the later in the project they arise!