NZ building code updates to H1 Energy Efficiency.

Ministry of Business, Innovation and Employment have changed the building code requirements for the H1 Clause of the New Zealand Building Code. The H1 Clause regulates the energy efficiency of our built environment – covering wall, floor and roof insulation as well as the thermal performance of windows and doors. There are a range of requirements, transition and implementation periods, depending on building type, construction element, and Climate Zone.

This article is intended to provide our valued customers with and an overwiev of some of the changes that are in realtion to windows and doors.

The new law apply to all housing (including medium-density housing, apartment buildings and other multi-unit housing) and to buildings other than housing up to 300 m2. That is the scope of this Guide.

NEW CLIMATE ZONES

There are now six Climate Zones based on the average climate of each area. A building’s Zone is dictated by the building’s site address. Zones are paired for windows and doors into Zones 1 & 2, Zones 3 & 4 and Zones 5 & 6.

Climate zones 1 & 2:

Northland
Auckland
Coromandel
Bay of Plenty
Hamilton
East Coast and Taranaki

Climate zones 3 & 4:

Manawatu
Horowhenua
Wellington
Nelson
Marlborough
Chatham Islands
Central Plateau
Wairarapa
West Coast

Climate zones 5 & 6:

Canterbury
Otago
Southland
Stewart Island

Source: https://www.wganz.org.nz

R-VALUE

The changes happening are based around R-values, so it is important to know what these are.

The thermal resistance rating or R-Value is the measure used most commonly in the building and construction industry to determine material’s ability to resist the transfer of heat.

In other words, R-value of a window measures how much heat is stopped by window and kept inside the building. The higher the R-value, the better the window at resisting heat transfer.

R-Value = Thickness (m) / Thermal conductivity (W/mK)

Requirements for R-value before the changes have been made were R0.26, which was achieved by most of double glazed aluminium frames that were commonly used in New Zealand.

The new minimum R-value requirements will vary depending on the climate zone new house is intended to be built in and can be achieved in new homes with various solutions such as heat reflective glass with lowE coatings, uPVC or timber frames, or aluminium thermally broken frames.

Currently, and it has started from 2 November 2022, the requirements for R-value are R0.37, however the standards have been raised and put into the following transition periods:

From 1 May 2023:

R0.46 for climate zones 3 & 4
R0.50 for climate zones 5 & 6

From 2 November 2023:

R0.46 for climate zones 1 & 2

R-VALUE OF SELECTED GENERIC WINDOWS AND DOORS

Ug of Glass	Glass Spacer	Glass Example	Aluminium Frame	Thermally Broken Aluminium Frame	uPVC Frame	Timber Frame
2.63	Aluminium	Glass: Clear/Clear Gas: Air	R0.26	R0.32	R0.40	R0.44
1.90	Aluminium	Glass: LowE/Clear Gas: Argon	R0.30	R0.39	R0.50	R0.56
1.60	Thermally Improved	Glass: LowE/Clear Gas: Argon	R0.33	R0.42	R0.56	R0.63
1.30	Thermally Improved	Glass: LowE/Clear Gas: Argon	R0.35	R0.46	R0.63	R0.71
1.10	Thermally Improved	Glass: LowE/Clear Gas: Argon	R0.37	R0.50	R0.69	R0.77

Source: https://www.wganz.org.nz

VTITE THERMAL PERFORMANCE

Regardless the climate zone, our uPVC products exceed new thermal expectations. Standard VTITE windows meet an R-Value of R0.56 and VTITE+ can achieve R1.35 when triple glazed. All our windows and doors are labelled with R-value information, which is calculated for each item individually. The calculations are made by innovative production software and are based on relation between two areas: glass and uPVC frames, taking into account their thermal performance and kind of glass spacer being used for separation and sealing of two or three panes of glass. Please contact our team for more information.

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