BRANZ Calculation Method Tool v10 Basic (December 2025)

The webinar covers:

• What the H1 Calculation method is and when to use it
• Reference houses and how these are calculated
• The advantages, disadvantages and limitations of the calculation method
• Tricks + tips how to make it useful
• How to use and verify the output.

• Please note: that access to this webstream will expire after 1 month.

This Microsoft Excel (.xlxs) 25MB download of BRANZ House Insulation Guide 6th edition is for PC users.

Updates:

• Further fix to error where the R-value for slab floors were higher than they should have been when adding floor topper insulation
• New images for timber framed floors
• A worksheet added which provides simplifications to help with calculation and modelling for steel framed walls

The guide is now in two parts:

• The tables of construction R-values for common construction options for compliance under H1/AS1 and H1/VM1 5th edition
• The accompanying House Insulation Guide text [PDF] for guidance on insulation to meet or exceed H1 AS/1 and H1/VM1 5th edition.

In this free 20-minute module, you’ll learn about some of the key challenges to achieving or exceeding the new performance requirements to comply with H1 Energy efficiency. The focus is on H1/AS1 and H1/VM1 5th edition amendment 1.

Topics include:

• What are construction R-values?
• Roofs – sloping and skillion
• Floors – underslab heating and slabs with attached unconditioned spaces
• Windows – compliance and avoid overheating
• Doors – compliance and opaque doors
• Walls – compliance and improved performance
• Secondary insulation – improve performance for walls and roofs

This Microsoft Excel (.xlsx) tool automatically applies the calculation method of H1/AS1 6th edition  and generates a results page that can be used to demonstrate compliance.

Features:

• Introduction
• Project details
• Slab floors
• Other floors
• Roof
• Skylights
• Walls
• Glazing (walls and doors)
• Doors (opaque)
• Results

More information here.