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.