Insulation - The Inside Track
October 24, 2024
Insulation has been a hot topic lately. Clause H1 of the New Zealand Building Code was updated last year, introducing new insulation standards to improve thermal performance in Kiwi homes. Despite the changes happening quite recently, the Government is already questioning the new H1 standards and considering a review. So what’s the issue, and what does it mean for builders and tradies fitting out homes?
The new H1 standards have been a divisive topic of conversation in the building community. Supporters say the changes are vital for improving housing stock, lowering energy use and carbon emissions, and that they also bring us into line with standard practice in other countries. Those against the changes say they’re too expensive, adding to the already high cost of new homes, and that the standards can cause overheating.
There’s a growing consensus across the construction sector that the issue isn’t with the new rules, but with how they’re being applied. EBOSS and New Zealand Certified Builders calculated that the costs of complying with the new rules could be less than a tenth of the $40,000-$50,000 that some were suggesting. The issue is with how insulation solutions are designed.
There are three methods designers can take to calculate insulation requirements on a build – the schedule method, the calculation method, and the modelling method.
The schedule method is proving ineffective for the new requirements. This method simply adds up the components, and as a result it can lead to over-costing projects.
The best, and by far the cheapest, method for most homes is the calculation method, which lets designers mix and match different insulation elements to get the best result. The modelling method is best used for homes where the window area is more than 40% of the wall area.
The BRANZ website has some great tools to help you use the different methods and work out exactly what’s needed, including webinars and how-to guides.
It’s worth remembering that insulation doesn’t make homes hot. It actually keeps the indoor temperature more stable and comfortable throughout the year, helping keep the warmth in during winter and keeping it out in summer.
The good news is it’s possible to have international-standard insulation without breaking the bank for stretched homebuyers – it just takes the right tools.
