H1 Building Code

H1 Building Code

The Building Code clauses include Objectives, Functional requirements and Performance criteria. These are mandatory provisions that all new building work must comply with.

Key Background Information

The H1 Clause of the Building Code regulates the energy efficiency of our built environment - covering wall, floor and roof insulation as well as the thermal performance of windows and doors.

Proposed changes to the Clause were consulted on last year and published in November 2021 – there are a range of requirements and transition and implementation periods depending on building type, construction element and climate zone.

Proposed changes to the Clause were consulted on last year and published in November 2021 – there are a range of requirements and transition and implementation periods depending on building type, construction element and climate zone.

The next step in this transition period comes into effect on 23rd May 2023 and then all requirements will be effective as of 2nd November 2023. (Please note further information on these compliance transition periods and requirements have now been published by MBIE in August 2022).

H1 Building Code

Key Contextual Changes:

Energy Efficiency is top of mind, with this update being one of the first steps in the Government’s Building for Climate Change programme.

There are major increases in thermal performance requirements across the building envelope. Some of the most significant ones are to Window and Glass solutions.

There has been the introduction of new Climate Zones.

In the background there’s been a shift in R-Value calculation methodology from a single window philosophy to the weighted average of a modern house lot of windows. This is the base for the minimum R- Values Table in H1/AS1.

New Climate Zones:

There are now six climate zones based on the average climate of each area.

Zones are paired for Windows and Doors into Zones 1&2, Zones 3&4 and Zones 5&6.

A building’s Zone is dictated by the building’s site address (not he clients base or supply area)

New Climate Zones

Overview of Construction R- Values

This table from H1/AS1 shows the R-Values for Various Glass and Framing combinations for vertical windows

This table is used as part of the method used when demonstrating the compliance of a frame and glazing combination. Other configurations will require individual calculations or methods eg. opaque doors, doors with pet doors, louvres, colonial bars etc

Please Note: Thermally Improved in the Glass Column refers to a spacer between the panes that meets the definition in ISO 10077-1 Annex G The examples provided are informative descriptions only of the IGU types that might be use to deliver the nominated Ug Values. The properties of each of the glass panes within the IGU are provided and separated by ‘/’. ‘Clear’ refers to Clear Float glass. Low E1, Low E2, Low E3 and Low E4 refer to glass with low emissivity coatings at different performance levels

R-Values for Various Glass and Framing combinations
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Important Dates:

• Zones 5 & 6 from 3rd November 2022 to 30th April 2023

• The transitional R-Value during this period is R0.37

• Minimum compliance can be achieved through the use of Double Glazed Low E IGUs in Aluminium Frames

• Thermally Broken Aluminium and UPVC frames with double glazed Low E IGUs already meet or exceed the standard

• Higher spec solutions can always be used earlier and will result in a more thermally efficient home.

• Zones 5 & 6 from 1st May 2023 Onward

• The required R-Value will become R0.50

• Compliance requires Double Glazed Low E IGUs combined with:

• Thermally Broken Frames or uPVC Frames

The new implementation plan for Windows and Doors sees all Zones move to R0.37 on 3rd November 2022 – this enables an improvement in energy efficiency to be achieved sooner through the use of Low E IGUS (Insulated Glass Units)

The second phase of transition comes into effect six months later on 1st May 2023

The final requirements are in effect as of 2nd November 2023

Windows and Doors Climate Zones

How Aitken Joinery can help you meet the new Standards

We have Options for both stages of the H1 implementation as follows:

Until April 30th 2023 as a minimum you can choose to have either Residential/Metro Thermally Broken Frames and Low E E Saver Double Glazing or Residential/Metro Aluminium Frames and Low E Lightbridge with Argon Gas Doubled glazed units.

From 1st May 2023 you must have Residential or Metro Thermally Broken Frames with Low E Lightbridge Argon Filled doubled glazed units or UPVC Frames with Low E Lightbridge Argon Filled doubled glazed units.