Meet Marcel Herbke

“The new H1 requirements are in line what we’ve already recommended for a long time.”

“Whenever you have structural elements that aren’t insulated, they will create weak points for heat to escape,” says Autex New Zealand’s General Sales Manager, Marcel Herbke.

This is known as thermal bridging, Marcel says, a known insulation challenge which Autex has long addressed by recommending double-layer insulation systems. This year, that approach is paying dividends as the New Zealand building industry looks to meet increased insulation standards in line with the new H1 code. “These updated requirements have been rolling out in a staged way for the last couple of years, but will come into full effect in May. There are some broad changes to the way the industry is viewing the New Zealand climate, such as an increase in nationwide climate zones from 3 geographical areas to a total of 6, but there are specific requirement increases coming into play as well.”

The most significant of these is a sizeable increase in the required R (thermal resistance) value of New Zealand buildings. “To put it into perspective,” Marcel says, “the minimum requirement for a roof in the North Island was previously an R-value of 2.9. With the new standards, this has been increased to an R-value of 6.6. Obviously, this is quite a significant jump. It’s not perfectly linear, but this new standard works out to be about twice the insulation performance as was required previously.”

“Whenever you have structural elements that aren’t insulated, they will create weak points for heat to escape,” says Autex New Zealand’s General Sales Manager, Marcel Herbke.

Autex has long promoted the use of double-layer insulation, Marcel says, which has comfortably placed the business to get out ahead of these new requirements. “If you have timber in the rafters, you’re going to lose heat through those structural elements. The gaps between the timber and your insulation will create a thermal bridge. And there’s no point in paying a premium to meet the new standard R-value of 6.6 and then still having heat escape. Our double-layer insulation is installed with perpendicular layers, meaning that we can prevent that thermal bridging with a product solution that already meets or exceeds the new H1 code.”

Autex’s GreenStuf insulation range is made from 100% polyester, is non-toxic and is safe to handle without PPE. This means that it’s more than compliant, Marcel says. “It also contributes to better indoor air quality and is environmentally sustainable. Our polyester is made from recycled PET plastic that has been removed from the waste stream, making it particularly advantageous for Green Star builds.”

Marcel says that Autex insulation also more than competes on durability. “One of its biggest benefits is that it is moisture resistant. We had people telling us after the recent floods in the North Island that their underfloor GreenStuf insulation didn’t require any repair or replacement because it had simply dried out. Polyester insulation also won’t lose its structural integrity over time like some other types of insulation on the market. Materials like fibreglass absolutely will meet the building code for the first 5-10 years, but may slump after that, due to both the environment of the build and also interaction with the material, like if an electrician needs to access the insulated area.”

Autex’s double-layer insulation recently became the first double-layer insulation system to be BRANZ appraised, Marcel says, giving industry professionals additional confidence in its ability to do the job well. “BRANZ gives us a third-party, independent verification of the system’s performance. The appraisal involves submitting details about manufacturing processes and installation practices, as well as providing samples for review. Having that BRANZ approval now gives an extra layer of assurance for architects to specify Autex products with confidence.”

To further support the New Zealand building industry, Autex is working closely with construction professionals to demystify the updated code. “For every build, you now need to do an H1 calculation for your local Council to show that the structure you’re proposing meets the updated thermal requirements. The code allows you to offset one lower-insulated element like windows, for example, with a higher R-value element like the roof in order to raise the average thermal performance of the build. To do those calculations is complicated and time-consuming for architects. So as part of Autex’s standard service we’ll do them for you free of charge, as well as providing you with direct specification support. Architects can send us plans and we’ll make sure that the build they’re proposing meets the updated requirements.”

Energy efficiency is the most important consideration, Marcel says, alongside occupant health. “From both a power standpoint and a wellbeing standpoint, the heat that New Zealanders are paying for should not be escaping out of their homes. We’re committed to lifting the overall standard of New Zealand’s housing stock and constantly looking for ways that we can improve and push these discussions even further.”

To learn more and connect with Marcel, visit or contact the Autex GreenStuf sales team at

Bex De Prospo
Bex De Prospo