Glass is a key part of all our homes – from toughened, ultra-clear glass for minimalist bathrooms to colourful laminated or printed decorative glass for kitchen splashbacks and benches, doors, partitions, windows, or feature walls – glass holds an important place in all our homes.

In recent times, the performance of windows has been a major focus for the Government in increasing the quality of our housing stock. And, as a result, there are changes coming to the New Zealand Building Code (specifically clause H1 Energy Efficiency). Luckily for you, we’re here to help guide you through what these changes will mean for you and your home.

Most importantly, the changes will deliver warmer, drier, and healthier homes which generate carbon savings through this energy efficiency and aim to eliminate a large percentage of heat which escapes from your home through your windows. So before you start your next renovation or building project, read on for all the details, then find a local NZCB builder here to help ensure your next project meets the new standards.

What are the current requirements vs the new ones?


At the moment, the current energy efficiency requirements can be met with a standard aluminium frame and clear double glazing, no matter where you are in the country. 

Under the new requirements, there will be three factors to consider – your local “climate zone”, your frame type and your glass type. All New Zealand territorial authorities will be delegated climate zones. The map below from Ministry of Business Innovation and Employment (MBIE) illustrates the Climate Zones and Territorial Authority Boundaries.

In addition to your local climate zone, there will be an increase in the minimum insulation level for windows, so  you will need both thermally broken aluminium frames, (or timber or uPVC) and low emissivity (Low E) double glazing at the very minimum.

This standard covers all residential homes, apartment buildings and group dwellings.

The nitty gritty details

This section really just details for the professionals, or if you want to be super-thorough and double-check your builder has covered everything off.

For windows, new consents will need to meet a new interim level from November 2022.  H1/AS1 provides a schedule method for simple compliance where the window to wall ratio is 30 per cent or under, covering most housing. The new fifth edition H1/AS1 and H1/VM1 documents will be published this month (August 2022).

From November 3, this year, all double glazing will need to have Low E glass to meet the minimum standards Rwindow 0.37

The level of Low E required is proportional to the thermal performance of the frame type. Standard non-thermally broken frames can still be used for consents across the country until April 30, 2023, using Low E Xcel, minimum U value 1.1.

And finally, Low E Max minimum U value 1.5 can still be used in all zones in a thermally broken frames until April 30, 2023.

If you have any concerns, talk to your NZCB builder in the first instance.

So how will this affect your costs?

Based on a standard residential build, with cold frame and standard glass, an upgrade to cold frame, Low E glass, you may be looking at an increase of 10-15 per cent on a window package. To upgrade to warm frame and Low E glass you may be looking at an increase of 25-35 per cent on a window package.

As for the glass in the rest of your home, there are currently no changes to the safety requirements in the Building Code updates.  Both safety glass, either toughened or laminated, will still be the norm for all areas of human impact as per NZS4223.3.  For balustrades and pool fences, it is also important to comply with the PS1 requirements of the systems.

Final thoughts

Today’s modern, high-performance glass allows architects, designers, and homeowners to create striking interiors and exteriors, from large Low E window spans which bring the outdoors in and offer uninterrupted views of stunning scenery, to glass sliding doors which blur the lines between indoor and outdoor living, or simply partition one room from another for privacy.

With all of the incredible glass options, one of the most important things to do is ensure you choose the correct glass for your windows. Talk to your NZCB builder about what your needs are and they can guide you.

To find a nearby NZCB builder to help you with your plans, use the Find A Builder search function.