H1 Compliance Calculator

Christmas and New Years Special


Need an H1 report in a rush?

Have your H1 calculations done by us. For a short while we offer to do your residential H1 calculations for you. Prices start from $200+GST and turn-around times are usually three days or less.


Just send me your plans (as PDF files) together with your preferred insulation type (designnavigator@gmail.com). I'll have a look at them, let you know whether I need more details and and will give you a quote.

I hope this takes a bit of the pre-Christmas pressure away and you will enjoy a relaxed and wonderful Christmas and New Years break.

Sunny regards

PS: In case you are wondering: We can also do H1 calculations for commercial buildings.

The Design Navigator H1 Calculator is temporarily unavailable for maintenance and upgrades. It should be available again within 24h.

Sorry for any inconvenience.


This website calculates compliance with insulation targets of NZBC, Clause H1 as of 10 October 2011. It calculates compliance with the New Zealand Standard NZS4218:2004, Schedule and Calculation Methods, using the R-value targets from NZBC/H1 (October 2011) and for compliance with the Building Performance Index (BPI).

The Calculator should be used in conjunction with NZS4218:2004, which can be purchased from Standards New Zealand and the Energy Efficiency Clause H1 of the New Zealand Building Code. Note that the 2009 version of NZS4218 is not the Acceptable Solution for NZBC Clause H1 until the H1 Approved Documents refer to it. It is not clear when this will happen. Until this is the case NZS4218:2004 (modified by the R-values listed in Clause H1) is the Acceptable Solution for H1.

This program is distributed without any warranty and the author is under no circumstances liable for any undesirable consequences arising from the use of this site. The local BCA has authority to accept or reject the output of this Calculator.

To get started watch the video tutorial here .

I have recently added a feature that allows users to trace a scanned image of a floor plan. The training video for this new feature can be found here .

On Tuesday 24th September the server which hosts the Design Navigator website had a serious crash. Unfortunately the database storing the projects has been affected by this and I had to replace it with a backup version from Sunday 22 September. Any projects created inbetween have unfortunately been lost. Sorry about this.

The server crashed on 24 November. I am currently trying to recover the database and hope to have it done by the end of today (25 November). Sorry about this.

The server crashed late morning on 21 March 2014. The ISP has recovered the database, however some projects created on the 20th and 21st March might be corrupted or deleted. There was another crash on 25th March that may have also corrupted some data. Sorry about this.

I have recently updated the Design Navigator H1 calculator. The main new feature is that the calculator can now also calculate compliance for buildings with mixed wall construction types, i.e. non-solid walls and solid walls in the same building. There is also more detailed compliance information shown on the main page and the report view page has changed. If you find any bugs but please let me know (designnavigator@gmail.com)

Thanks very much


There currently is a bug in the Design Navigator H1 calculator, which is probably caused by changes which the ISP implemented recently.

Projects cannot be saved if they include a *previously* created construction R-value calculation table (view screen shot). The bug does not seem to occur for projects with *newly created* construction R-value tables.

You can still modify old projects and print the reports. You can also save projects, but before you do that you have to replace the old construction R-value tables with newly created ones, even if they are for the same detail.

I am working on fixing the problem.

In order to be able to save your project and to print out the compliance results you need to log in.

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Forgot your password? Enter your user name above and click this button. Your password will be e-mailed to the e-mail address in your profile.
Click here to use the H1 calculator without saving and printing of projects.

Note: I am regularly adding further improvements to this calculator. I am always trying to conserve any previously saved projects but suggest that you keep printed copies of the compliance reports so that you can reproduce the results should the database records be damanged.

Home This tool was created by Design Navigator Ltd.