In 2003, thermal performance requirements for residential buildings were added to the Building Code of Australia for the first time. The initial performance requirement was 4 Stars in the National House Energy Rating Scheme (NatHERS) as simulated using the benchmark software AccuRate. In 2006, the requirement rose to 5 Stars, then to 10 Stars in 2010. This all sounds great. The increasing rating requirements of NatHERS provides a measurable and predictable target for improving the energy efficiency of Australian homes. But the building products industry wanted to know, how accurate is AccuRate?

200: How Accurate is AccuRate?

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A ‘green’ home is the foundation of living a green lifestyle. Join me as I interview leading architects from around the world and discuss the how, why and who of eco homes and sustainable design.  From simple energy saving tips to insulation upgrades, kitchen remodelling, solar power and insulating concrete slabs. #Feedback to matthew@homestylegreen.com

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This week I attended a BRANZ seminar titled 'Building for our changing climate'. Tāmaki Makaurau Auckland was the last stop on the BRANZ seminar tour of the country and it's encouraging to think that rooms of designers, builders, product suppliers, building officials and others, were interested enough in this topic to take four hours out of their week.  A key takeaway is that we're not prepared. We're already handicapped by having insufficient standards in our building code to deal with our current climate. With the forecast being 'warmer and wetter', the situation is set to get worse. https://homestylegreen.com/?p=5936

Build Aotearoa 10: Warmer and Wetter

Steve Penny is the founder and director at Honoris, a building services consultancy in Christchurch, New Zealand. He is also the host of his own podcast,  A Penny for Your Thoughts.

Build Aotearoa 9 with Steve Penny

 Many people might be surprised to know that the New Zealand Building Code does not require any consideration of overheating in homes. The energy efficiency requirements in our code are based only on the ability of buildings to keep warm without excessive heat loss. There is nothing to prevent homes from being designed with large areas of unshaded north or west-facing glass.   Siân Taylor is an Architect and Passive House Designer based in Queenstown. She has experience creating homes that are designed to perform well all year round, in some of the most challenging and spectacular locations.   Follow Siân on Instagram and check out Team Green Architect's latest work at https://www.teamgreenarchitects.co.nz/. 

Build Aotearoa 8: Cool by Design with Siân Taylor

Stärke has been in the window industry in New Zealand since the 80s. They were at the forefront of supplying aluminium frames to the building industry but have recently made some big changes. With a focus on building performance, Benjy Simmons describes the new direction of Stärke as a 'once-in-fifty-year' change. While the company has a long legacy, they've experienced rapid change over the last few years.  Benjy credits some of the openness to change to him being from outside the industry. He's come in with a different perspective. "We're beginning to see ourselves as a building performance company not just a window and door company", says Benjy.  Check out the full range of Stärke products along with their education pages and other resources.

Build Aotearoa: Changing the Window Industry with Benjy Simmons

 More is not always better, especially regarding the amount of timber in the frame of a house. The more timber there is, the less space there is for insulation. The way this is measured is called timber fraction. Most homes in Aotearoa are designed using the assumption that timber will make up around 14% - 18% of the area in a wall. A 2020 BRANZ research study found that in reality, the average timber fraction is closer to 40%. This means there is considerably less space available for insulation.   Unfortunately, this is not always picked up during the consenting or pre-lining inspection process. H1 Energy Efficiency calculations are checked at the design stage, usually using the much lower default timber fraction assumption. The result of all this is that many consumers are effectively getting less insulation than they're paying for, and much more thermal bridging.    PlaceMakers has recently launched a new service providing a detailed report of the actual timber content for any wall frame and roof truss they supply. This accurate figure can then be used to provide true H1 calculations. Alternatively, a designer might choose to adapt their plan to reduce the thermal bridging and increase the amount of insulation.   National Technical Resource Manager, Pete Hammond explains how Framology works. We also discuss the option of using external insulating products like RigidRAP-XT from IBS to eliminate thermal bridges. 

200: How Accurate is AccuRate?

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