Compares your building's heat loss (Σ A/R) against the H1/AS1 reference building for your climate zone. The example values are a sample 160 m² single-storey Auckland house; replace them with your own.
Have a suggestion or an improvement that would make this calculator more useful?
Email Shahram@expol.co.nzNeed technical advice?
Contact our team at tech@expol.co.nzThe map highlights the selected climate zone and boxes the council's name. Enter a postcode to pick the council automatically, or choose it from the list. Click a name on the map to select that council, or click anywhere else on the map to enlarge it.
Construction R, not the batt R. A 90 mm timber wall with R2.8 batts is about R1.6 once the default 38% framing fraction is applied. Use a build-up to pick cladding, framing and batts; a framing % below 38% needs a framing calculation for the consent.
No floors added yet. Use "+ Add floor" to add floor 1. If no floor is part of the thermal envelope (for example an upper apartment over another heated unit, H1/AS1 2.1.2.4), leave this empty.
Mixed slab perimeter and external A/P (Advanced) apply to floor 1 only; use floor 1 for a slab that needs them.
Blank R-values use the H1/AS1 2.1.2.13 unknown defaults: 0.15 for windows, 0.18 for opaque doors. Skylights have no default and can't use the window table: their R must be calculated to ISO 10077-1 (H1/AS1 D.2, R = 1/Uw). Until it is entered, R0.15 is used as an estimate and the check fails.
Use these when the slab perimeter isn't all the same: brick on some walls only, or no edge insulation along a wall to an attached garage or under door openings.
Councils check that every number traces back to a source. Areas are measured to overall internal dimensions (H1/AS1 2.1.2.10). Add an evidence reference for each roof and wall R-value; the report flags any that are missing.
Something look wrong, a question about a result, or an idea to make this tool better? Email EXPOL's technical team at . If it's about a particular house, attach its saved project file (Save project) or the PDF.
This free calculator from EXPOL checks a New Zealand house against the H1/AS1 6th edition calculation method. It adds up the heat loss of every part of the building envelope (area ÷ construction R-value, written Σ A/R) and compares it with a reference building of the same size in your climate zone. If the house loses no more heat than the reference building, and every minimum R-value is met, it passes.
Architects, building designers and builders preparing the H1 energy efficiency part of a building consent for housing.
The calculator covers housing under H1/AS1 6th edition (calculation method) only. It is a design aid, not a building consent approval. The designer remains responsible for the areas, R-values, evidence and the consent submission. EXPOL supplies the slab R-value evidence only and accepts no liability for Building Code compliance or the thermal performance of the building. Check the Acceptable Solution itself where in doubt.