Changes to Building Code energy efficiency provisions: insulation, lighting and solar water heating
From 31 October 2007, tougher standards apply for the thermal performance of every home built in the South Island and North Island Central Plateau. In most instances, this will mean the use of window double-glazing and more insulation in walls and roof. By October 2008, all new homes throughout New Zealand will need to meet these new requirements. The new rules also apply to most buildings with a floor area less than 300m2, and to all major extensions.
From 31 October 2007, tougher minimum standards also apply for lighting in commercial and other large buildings.
Getting a building consent to install solar water heating will be easier with the publication of a solar water heating Acceptable Solution G12/AS2.
Changes to Building Code Clause H1 (Energy Efficiency)
Changes to the Building Code announced in May will see:
- better insulation for new homes (typically including double-glazing) resulting in about 30 percent less energy needed to achieve comfortable indoor air temperatures.
The Building Code has been amended to toughen the BPI (Building Performance Index). The BPI definition has also been adjusted (see NZBC Clause H1.3.2).
A corresponding change to the H1 Compliance Document updates the referenced Standard, using a modified NZS 4218: 2004 in place of NZS 4218: 1996. The R-values specified in NZS 4218: 2004 have been modified with higher values that match the thermal performance required by the new Building Code BPI (see H1/AS1 and H1/VM1).
Note: the new Building Code requirement and the replacement R-values will take effect at different times throughout New Zealand (see below for details).
- improved efficiency of lighting in new and refitted commercial buildings, and certain other large buildings, which will reduce the average power consumption of lighting installations by around 33 percent.
No change has been made to the Building Code, but the Acceptable Solution H1/AS1 has been amended to use the recently updated Standard NZS 4243: 2007 Parts 1 and 2, instead of NZS 4243: 1996.
This update reduces the maximum allowable lighting power density in commercial buildings from 18 W/m2 to 12 W/m2 on average, with corresponding changes to COMMUNAL NON-RESIDENTIAL. The update also accounts for lighting controls.
Note: the Building Code requirements for lighting apply only to COMMERCIAL and COMMUNAL NON-RESIDENTIAL buildings.
- easier approval of solar water heating systems across New Zealand through a new Acceptable Solution, which specifies the necessary features that a solar water heating system should have to comply with the Building Code.
The Department has clarified the requirements for installing solar water heating systems in an Acceptable Solution, G12/AS2. No change has been made to the Building Code, but the new Acceptable Solution brings together all the relevant Building Code requirements for installing solar water heating systems. Consideration is given to the structural integrity, weathertightness and durability of the installation, and the heath, safety and efficiency of system operation.
Timing of the changes
Building Code amendments and updated Compliance Documents published
|31 October 2007
Building Code and Compliance Document amendments become effective
|Increased thermal performance requirements come into force in zone 3
|Increased stringency for commercial lighting comes into force throughout New Zealand
|30 June 2008
Increased thermal performance requirements come into force in zone 2
|30 September 2008
Increased thermal performance requirements come into force in zone 1
Above: map of climates zones
Compliance with H1
The following ways can be used to show compliance with H1 requirements for thermal performance.
- Building Code - Clause H1.3.2
BPI (Building Performance Index) ≤1.55
- Acceptable Solution - H1/AS1
Schedule Method (NZS 4218: 2004) Calculation Method (NZS 4218: 2004)
- Verification Method - H1/VM1
Modelling Method (NZS 4218: 2004)
The following ways can be used to show compliance with the H1 requirements for artificial lighting.
- Building Code - Clause H1.2(c) and H1.3.5
- Acceptable Solution - H1/AS1
Schedule Method (NZS 4243: 2007, Clause 3.3) Calculation Method (NZS 4243: 2007, Clause 3.4)
The Department has published an information booklet, entitled Your Guide to $marter Insulation, detailing the changes. Copies are available from the Department's website, or by phoning 0800 242 243.
Copies of the new Building Code clause and Compliance Document for H1 can be freely downloaded from the Department's website at: www.dbh.govt.nz/compliance-docs-get-copies
Copies of the Standards can be bought at www.standards.co.nz
The BRANZ House Insulation Guide (Third Edition 2007) is a simple, easy-to-use guide that shows how much insulation is required for different types of house construction. The guide has just been updated for the new H1 requirements and can be bought at www.branz.co.nz