Residential buildings Residential buildings are Class 1 buildings, the sole-occupancy units of Class 2 buildings and a Class 4 part of a building. The proposed changes have focused on enhancements to the current energy provisions and improving interpretation and compliance. The proposed changes include: • introducing separate heating and cooling load limits to supplement the Nationwide House Energy Rating Scheme (NatHERS) star rating requirements, to improve the performance of dwellings throughout the year, particularly in times of extreme heat or cold • tightening the language for the reference building verification method and including more prescriptive modelling parameters • including the blower door test method for building sealing via an optional verification method • changes to the building sealing prescriptive provisions. A range of other minor changes have also been made to Part 3.12 to improve the existing energy efficiency provisions. Both BCA Volumes 1 and 2 have proposed the inclusion of a number of new measures to minimise the potential impact of condensation in buildings. This includes the use of vapour permeable membranes in certain climate zones, roof space ventilation and external ducting of exhaust fans and range hoods, under certain circumstances. While these changes may not seem to be substantive individually, collectively they will impact the residential building industry. In fact the changes may mean a number of current building designs require changes or will no longer be accepted. HIA participates on the ABCB’s energy COMMERCIAL The amendment includes: efficiency residential working group that was BUILDINGS WILL • changes to the energy efficiency performance consulted on these changes. As part of this requirement by attempting to prescribe a process HIA raised the practical application BE SUBJECT TO ‘quantified’ level of performance for buildings of a number of the changes and the potential SIGNIFICANT with a conditioned space implications they may have on different building STRINGENCY • adding new optional means of satisfying the typologies across the country. INCREASES BEYOND performance requirement JP1 by using NABERS Next steps THE CURRENT Energy or Green Star ratings. These will be listed REQUIREMENTS as verification methods allowing their use as part The proposed changes were released for public of a performance solution comment throughout February and March and • introducing an optional means of meeting comments closed mid-April. Going forward the building envelope sealing requirements by using ABCB and its technical advisory committees will the ‘blower door test method’. consider the public comments and endorse a final A range of other changes have also been made version of BCA 2019. This will be released as a to the Deemed-to-Satisfy provisions, including the preview early next year, prior to taking effect in provisions for fabric and glazing, sealing, May 2019, subject to any state and territory air-conditioning and lighting. transitional periods. The impact these changes are expected to HIA will provide further advice to members on have on the commercial building sector and those the approved changes when the final version is supplying products for commercial buildings is released. Members are encouraged to review the extremely hard to gauge. The current Section J public comment draft on the ABCB website to provisions are complex and the proposed changes prepare for any changes your business may need would make them even more complex. HIA’s to make to house designs or approval processes. discussions with members suggest the changes will Visit www.abcb.gov.au to review the public have a significant impact. comment draft. 40 HOUSING MAY 2018 IN FOCUS • ENERGY EFFICIENCY