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NCC 2022 energy efficiency and condensation provisions
Proposed amendments to the NCC 2022 energy efficiency and condensation technical provisions
On the 1st of February 2019 the Energy Ministers agreed to the Trajectory for Low Energy Buildings, a national plan that sets a trajectory towards zero energy (and carbon) ready buildings for Australia. This report focussed on improving new buildings. NCC 2022 is part of this body of work.
After a major stringency increase for commercial buildings in NCC 2019, , Building Ministers directed the ABCB to develop enhanced residential energy efficiency provisions informed by the former COAG Energy Council’s Trajectory for Low Energy Buildings policy.
This work supports the Australian Government’s commitment under the Paris Agreement to reduce greenhouse gas emissions, and the National Energy Productivity Plan.
These policies all include a focus on the role that buildings play in reducing emissions, improving energy productivity, reducing household energy bills and helping to transition to the greater use of renewable energy and zero emissions vehicles.
The following is an overview of the major changes that will be implemented in the NCC 2022.
SUMMARY OF MAJOR CHANGES
1. Stringency increase the Star Rating
2. Whole of home energy use requirements added
Measure
Increase in thermal performance from the current level, equivalent to 6 Star NatHERS, to the equivalent of 7 Stars. Higher window and glazing performance Increases in ceiling and wall insulation
R-values Restrictions on wall and roof colours Changes to structural floor systems (insulated slabs or sub-floor insulation.
What’s likely to be involved?
Measure
Whole of home annual energy use requirements.
Differences between Class 1 and Class 2 Buildings. Introduction of a collective energy use budget for; Hot water systems Lighting Swimming pool and spa pumps
Ability to trade between the efficiency of systems for annual energy use budget. Onsite renewables may be installed to offset the energy consumption of the equipment but not the building fabric.
What’s likely to be involved?
As well as meeting the 7-Star requirement, new houses and single occupancy units (SOU) will need to meet a collective energy use budget for heating and cooling systems, hot water, lighting and swimming pool and spa pumps (where fitted).
The ABCB will provide a simple whole-of-home calculator to assist in quickly determining the requirements. The NatHERS Administrator is also working on expanding NatHERS beyond thermal comfort to incorporate whole-of-home requirements to align with the proposed NCC 2022 provisions. This will allow the whole of home assessment to be completed as part of the energy rating.
3. New deemed to satisfy elemental provisions (Class 2)
Measure What’s likely to be involved?
Increase in thermal performance from the current level, equivalent to 6 Star NatHERS, to the equivalent of 7 Stars. Higher window and glazing performance Increases in ceiling and wall insulation R-values Restrictions on wall and roof colours Changes to structural floor systems (insulated slabs or sub-floor insulation. Note, the thermal bridging mitigation measures proposed for NCC 2022 do not seek to totally eliminate thermal bridging by all framing. Instead, it proposes to reduce the thermal bridging of steel frames so the total R-Value of an element with steel framing is: no less than 95% of that for a timber-framed element for insulation R-Values of
R3.0 or less no less than 90% of that for a timber-framed element for insulation
R-Values above R3.0. This differential approach reflects the diminishing returns of insulation at higher R-Values.
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Renewable gas (such as hydrogen) provides all the great benefits of natural gas, but has zero carbon emissions. It’s already started making its way into homes in South Australia as a blend with natural gas, and in 2023 our HyP Murray Valley facility will blend renewable hydrogen with natural gas, at volumes of up to 10% to more than 40,000 connections. By continuing to support gas infrastructure, you will be ‘renewable gas ready’ when we start delivering. By 2030, we aim to have the whole of network supplied with a 10% renewable gas blend, with an aspiration to shift to 100% renewable gas by 2040.
4. Retrofit onsite renewables & vehicle charging
Measure
New provisions designed to allow easy retrofit of onsite renewable and electric vehicle charging equipment for Class 2 to 9 Buildings. New provisions designed for ‘solar ready’ zones for potential future installation of electric vehicle charging equipment for Class 2 to 9 buildings.
What’s likely to be involved?
New provisions are being proposed to enable Class 2, and 5 to 9 buildings to be easily retrofitted with DER. DER include photovoltaic (PV) panels, battery storage systems and electric vehicles (EV). The changes are intended to “future proof” buildings for retrofitting onsite renewables which in many instances are likely to become businessas-usual equipment for commercial buildings in future. The provisions do not require EV charging equipment, but are designed to make it much easier to install such equipment as EVs become more common over the coming decades.
Measure
Enhanced condensation management provisions.
NCC 2019 introduced specific condensation management for the first time. For NCC 2019 more substantive measures are being proposed. Changes to wall sarking requirements to more vapour permeable types equivalent to Class 3 or 4 membranes (depending on the climate zones).
Ventilating roof spaces that include; Providing air spaces for roofs Changes to roof sarking installation and roof sarking vapour permeability requirements. Additional roof space ventilation via installation of whirlybirds, ridge or eave vents or similar.
What’s likely to be involved?
5. Condensation management measures Notes: Changes to sarking requirements for Climate zone 4 to 8.
Plus:
Measure What’s likely to be involved?
Enhanced condensation management provisions. Exhaust system changes including; Minimum flow rates for exhaust fans Mandatory exhaust and ducting to the outside for exhaust fans and rangehoods Banning recirculating rangehoods Bathrooms not naturally ventilated must have exhaust fans with 10 minute runoff timer and Additional provision for ventilation to laundries/ bathrooms containing a dryer.
CONCLUSION
What will this mean for in practice?
Master Builders Victoria is currently in the process of organising NatHERS modelling for some housing designs to provide further information and evidence for members on the changes. From previous discussions with builders and energy raters MBV believe the following is likely:
Aspect is vital: Get the passive solar design correct from the beginning. Look for living areas and windows on the north side of the house. Reduce window sizes elsewhere.
For further information on Passive Solar Design principles visit Master
Builders Victoria’s Youtube page. www.youtube.com/ watch?v=YylmeMilok8 It will be easier to achieve 7-Star in single storey houses rather than double storey. Overshadowing by neighbours can reduce the star rating by 0.5. Maximum insulation (R6 ceiling. 2.5 walls). Most likely that all windows and doors in conditioned areas will need to be double glazed and thermally broken plus low-e glass for double storey
MBV understands the benefits of moving to 7-Star however; we are concerned that wider implications have not been fully considered and we continue to work with government on these issues. Theyinclude;
An increased risk of condensation and mould,
A rigid assessment pathway, planning and lot layout requirements not yet part of planning schemes, a rushed and late consultation process and industry upheaval and supply chain shortages.
As well as supply shortages the Industry has currently been hit by a tsunami of changes that are severely impacting on construction:
New accessible housing requirements will add significant cost, Supply shortages increasing costs of products with price increases of 30-50%, Changes to trade registration requirements and Impact of covid on the industry, especially the renovation industry in
Victoria and the risk of increased insolvencies in early 2022.
MBV believes a significant transition period of a minimum 2-3 years is required before new regulations take effect. This will provide time for;
1. The development of training and education for industry and consumers. For example;
• the development of and support for training of the industry around issues of condensation management and correct building techniques, • the development of housing displays
showcasing 7 Star houses. • allowing materials suppliers time to source and develop the window market, building membranes and product specifications and guidance.
2. Regulatory change to occur at an appropriate pace. For example;
• time for proper assessment of the changes and feedback through the RIS process, • inclusion of condensation management upgrades to the NCC, • planning changes for new developments requiring improved lot lay out for solar access and reduced overshadowing.
LOOK! UP AT THAT ROOF!
IS IT A KINKY EUROPEAN THING?
IS IT AN OVER-EXAGGERATED AMERICAN THING?
NO!
IT’S ABOVE SHEATHING VENTILATION!
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