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Understanding H1/AS1 Insulation Regulations

Let’s establish the situation; MBIE has proceeded with changes to the roof, window, wall, and underfloor insulation requirements by issuing the new edition of Acceptable Solution H1/AS1 and Verification Method H1/VM1 for housing and small buildings. The new insulation requirements aim to reduce energy needed for heating residential homes by approximately 40% over the minimum previous requirements. In this article, we will just be talking about insulation for concrete Raft foundations and how these standards relate.
 
Climate zones
It is important to first understand the zones; the changes to climate zones will better reflect specific weather in different parts of New Zealand. The aim in making these updates is to make sure homes and buildings are more suited to the climate where they are being built.
 
The six climate zones are based on thermal modeling of buildings using NIWA climate data files for 18 different climate stations. We only need to focus on the 6 zones shown here, download zones. 
 Insulation R-values
Here we focus on the requirements for concrete Raft Floors which can be broken into 2x categories; Foundations with underfloor heating systems and foundations without. Each have 6x climate zones of NZ and minimum R-values to reach accordingly, please refer to the zones diagram to find your minimum R value requirement. For example zones 1-4 are required to reach R1.5 in their (non heated) foundation performance for all of North Island and some Northern & Western areas of the South Island.
 
R Values Verification:
Relating this to your design; so how do we measure the R value? The thermal resistance (R-values) of insulation materials may be verified by using AS/NZS 4859.1. & ISO 13370: 2017 Thermal performance of buildings. It is important to note any testing of foundation insulation levels must be done to a level compliant with the verification methods mentioned here. QPOD contracted Sustainable Engineering Ltd. to perform thorough modeling and testing of the QPOD and associated Quickset insulation systems. The results are published and available in our Sustainable Insulation Methods Manual.
 
We have also made it easy to determine what system you need to achieve your minimum requirement R Value according to zone with The R Value Calculator, here you can input the area and perimeter of your foundation showing you the R value according to slab insulation system type.
PASSIVE HOUSE Ψ AND FRSISlab Passive House calculations of Ψ are in accordance with ISO10211:2017 with Passive House Institute (PHI) modifications and fRSI criteria. These use EXTERNAL DIMENSIONS and the heat loss at the sill plate (which should not be neglected) is included in this Ψ calculation. NZBC has no official requirements for a particular fRSI value but NZGBC Homestar V5 does have requirements Intended to parallel the Passive House requirements. In PHPP10 these will be calculated via a moisture balance for each specific building to allow lower fRSI values to be used as less conservative criteria are appropriate with more detailed knowledge of the building ventilation rates, loads, and heating set points.
FRSI REQUIREMENTS FOR NZ REGIONS FOR PASSIVE HOUSE
This map shows the three different fRSI zones at the weather station altitudes. The climate zone and thus the fRSIrequirements also vary with altitude as the average temperatures typically drop by 0.6C per 100m of elevation gain. In general thesezones can be used without considering the elevation change. Illustration: Sustainable Engineering Ltd. fRSI requirements from PHIPassive House Standard Building Criteria.