Introducing the Free EXPOL H1 Heat Loss Check

With New Zealand's updated H1 Building Code requirements, architects, designers and builders need a simple way to assess building performance and understand whether their designs meet the required energy efficiency standards.

To help make this process easier, EXPOL has developed the EXPOL H1 Heat Loss Check – a free online calculator designed to help you check H1 compliance, compare insulation options and make more informed decisions during the design process.

What Is the EXPOL H1 Heat Loss Check?

The EXPOL H1 Heat Loss Check is an easy-to-use online calculator that assesses building heat loss against the H1/AS1 6th edition Calculation Method.

Simply enter your building details, including the roof, walls, floors, windows and doors, and the calculator does the rest.

You'll receive a clear PASS or FAIL result, a detailed breakdown of your building's heat loss and a downloadable PDF report to support your building consent documentation.

Best of all, it's completely free, requires no login or installation, and runs directly in your browser.

Who Is It For?

The calculator has been developed to support:

• Architects and designers – check H1 compliance early in the design process and identify where changes may be needed.
• Builders and specifiers – compare construction and insulation options to understand their impact on building performance.
• LBPs and building professionals – assess heat loss and generate supporting reports.

Backed by Independent Thermal Modelling

EXPOL has invested in independent thermal modelling of its concrete floor insulation systems, giving designers access to evidence-based construction R-values rather than relying solely on generic H1/AS1 tables.

Undertaken by Sustainable Engineering Ltd, the modelling assesses a range of slab-on-ground and Tuff Pod floor configurations using the recognised H1/VM1 Appendix E two-dimensional heat-flow method and the tested thermal properties of EXPOL products.

The modelling covers different insulation combinations, including SLABX200 underslab insulation, ThermaSlab Edge and MAXEdge, across a range of floor sizes and perimeter configurations.

So how does this work in the calculator?

The EXPOL H1 Heat Loss Check automatically applies the relevant floor R-values. Simply enter your floor area and perimeter, and the calculator selects the applicable value, allowing you to compare EXPOL insulation options and see how they affect your building's overall H1 result.

The supporting evidence is also referenced in your downloadable PDF report.

Where a floor configuration hasn't yet been independently modelled, the calculator uses the applicable H1/AS1 table value or EXPOL in-house modelling where it provides a better result. The source of each value is clearly identified.

EXPOL continues to invest in thermal modelling and research to expand the available data and support designers with reliable, evidence-based insulation solutions.

What Else Can You Do With It?

The EXPOL H1 Heat Loss Check allows you to:

• Check whether your building meets H1 requirements.
• Compare your proposed building against the H1 reference building.
• Review heat loss across individual building elements.
• Compare different EXPOL floor insulation options.
• Download a detailed PDF report, export your data to CSV or save your project to revisit later.

The calculator covers residential housing under H1/AS1 and is designed to make the calculation process more accessible for professionals working across a range of projects.

Try It Today – It's Free!

Whether you're working on a new home design, specifying insulation or wanting to understand how different building elements affect heat loss, the EXPOL H1 Heat Loss Check is a great place to start.

Check your design. Compare your options. Make more informed insulation decisions.