H1/AS1 Calculation Method

H1/AS1 Calculation Method has been reproduced without amendment, as per H1/AS1 Fifth Edition Amendment 1.

2.1.3.1 This method compares the proposed building with the reference building, which is insulated in accordance with the Schedule method. This method permits roof, wall, floor, window, door, and skylight insulation combinations which differ from these tables, but the building must perform at least as well as the reference building.

2.1.3.2 The calculation method shall only be used where the glazing area is 40% or less of the total wall area.

2.1.3.3 Building elements that form part of the thermal envelope with construction R-values different from those in the Schedule method in Subsection 2.1.2 may be used, providing the heat loss of the proposed building (HLProposed) is less than or equal to the heat loss of the reference building (HLReference) for the relevant climate zone and window area.

2.1.3.4 HLReference shall be calculated using the equations in a) Table 2.1.3.4A. or b) alternatively, for housing only, for building consent applications submitted before 1 May 2023, those in Table 2.1.3.4B.

Table 2.1.3.4A: Reference building heat loss equations

Climate zone	Reference building heat loss equation
1, 2, and 3	HLReference = Aroof + Askylight / 6.6 + A70% of the total wall area / 2.0 + Aslab-on-ground floor / 1.5+ Aother floor /2.5 + A30% of total wall area /0.46.
4	HLReference = Aroof + Askylight / 6.6 + A70% of the total wall area / 2.0 + Aslab-on-ground floor / 1.5+ Aother floor /2.8 + A30% of total wall area /0.46.
5	HLReference = Aroof + Askylight / 6.6 + A70% of the total wall area / 2.0 + Aslab-on-ground floor / 1.6+ Aother floor /3 + A30% of total wall area /0.5.
6	HLReference = Aroof + Askylight / 6.6 + A70% of the total wall area / 2.0 + Aslab-on-ground floor / 1.7+ Aother floor /3 + A30% of total wall area /0.5.