Frequently asked questions

How do I know the calculations are correct?

Thermly's engine is validated against authoritative references, not just its own tests:

• The whole-building heat-loss calculation is checked against the official BRANZ H1/AS1 6th edition Calculation Method spreadsheet. The reference coefficients, minimum R-values, the 70/30 wall split, the glazing cap and the skylight-in-roof treatment all match, and the proposed heat-loss figure reproduces the spreadsheet across a large test set.
• The construction R-values are regression-anchored to the NZS 4214:2006 worked examples (F1, F2, F3 steel, F4 vented cavity).
• The method has also been reproduced against council-approved reports prepared with other tools.
• Every product R-value is sourced and shown with its provenance (see Product sourcing and provenance).

None of this removes your review. Thermly computes to the method faithfully; you confirm the inputs (areas, assemblies, product R-values) are right for the building. See How Thermly calculates compliance.

Who is responsible for a submitted report?

Sources and verification

This answer describes the professional-tool relationship - what Thermly does and does not do. It is the accurate description of the product, not a disclaimer bolted on.

You are, as the submitting professional, exactly as with any professional tool.

Think of how accounting software works: it does the bookkeeping arithmetic and produces the statements, and the accountant reviews and certifies the accounts. Thermly does the H1 thermal calculation and produces your consent-ready report; you, the submitting professional, review it and certify the compliance of what you submit.

Thermly computes construction R-values, runs the heat-loss comparison, and flags values that look unusual so you can check them. It does not certify, guarantee, warrant, or approve a compliant outcome, and it does not replace your professional judgement. That division is deliberate, and it is how the tool is built: Thermly computes and documents; the professional reviews and certifies. The report's own declaration says as much - it "does not constitute a certificate of compliance, council approval, or producer statement" - and it carries the name of the preparer and reviewer who stand behind it.

Can I use the report for consent submission?

Yes; that is what it is for. Thermly produces a complete H1/AS1 6th edition Calculation Method report: the heat-loss result, the per-element construction schedule and build-ups, the compliance checks, the required disclosures, your marked-up plan diagrams, and a declaration block.

Two things to be clear about:

• The report is the calculation and documentation, presented for a named professional to certify. It is not a compliance certificate, a producer statement, or council approval in itself, and it says so on the declaration. The building consent authority makes the compliance determination.
• Complete the declaration - the preparer and the reviewer. The report is strongest when a suitably qualified professional has reviewed it and put their name to it.

Used that way (your calculation, your review, your name) the report is built to go straight into a consent application.

Should I work from a plan or enter areas?

Either, and you can choose per element. Working from the plan gives you a measured take-off, a marked-up diagram in the report, an insulation take-off, and a plan-linked project. Entering areas directly is faster when you already have trustworthy numbers. The compliance calculation is identical either way. See Working from a plan or entering areas.

Which standards does Thermly implement?

Two:

• NZS 4214:2006 for construction R-values (the isothermal-planes method, surface resistances, cavities, slab lookups).
• H1/AS1 6th edition Calculation Method for the whole-building heat-loss comparison against the reference building.

Both are licensed standards; Thermly implements their methods so you do not have to work from the documents, though you remain the professional who certifies the result. See How Thermly calculates compliance.

What happened to the Schedule Method?

It was removed in H1/AS1 6th edition. From 27 November 2026 the Schedule Method can no longer be used; residential H1 compliance uses the Calculation Method (which Thermly implements) or the Modelling Method. The 5th edition and its schedule remain valid for consents submitted before that date. See The 27 November 2026 change.

Where do the product R-values come from?

From primary sources - manufacturer datasheets first, then the NZS 4214 and ISO 6946 reference tables - shown with their provenance via Show source on each product. Thermly does not use competitor calculators as a source. Many datasheet values are AI-extracted and should be checked against the current datasheet before use. See Product sourcing and provenance.

How do I enter a raft or proprietary floor?

A proprietary raft's R-value depends on your floor's geometry, so the manufacturer determines it per project. Run the manufacturer's calculator for your floor and enter the supplied R-value with its source document; Thermly records the basis (Appendix E, Paragraph E.1.1.1(b)) and uses the value verbatim. A plain slab uses the slab wizard instead. See Supplied floors and rafts.

Can I share projects with my team?

Yes. Create or join an organisation, then use shared folders that everyone on the team can see. Invite members by email with an Admin or Member role. Colleagues can add comments against each element at any status - a submitted project stays reviewable - and the In Review status marks a project as set aside for that final check. See Setting up a project.

Is my data private?

Your projects and plans are stored against your account and are visible to you (and, for shared projects, your organisation). Plan PDFs upload to secure storage and are available to view and download whenever you reopen a project.