Home Style Green Matthew Cutler-Welsh

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.

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/.

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.

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.

Denise Martin has been involved with many of Aotearoa's Passive House projects. As one of the most experienced blower door testers in the country, she's been involved with verifying a range of residential and commercial buildings both in New Zealand and Australia.

I caught up with Denise to chat about how she got into building science in the first place and some of the challenges and opportunities facing the building sector in New Zealand. We also discuss the building code, energy modelling, thermal performance and air tightness.

If you don't already, I highly recommend following Denise on Instagram, TikTok and LinkedIn.

I found it confronting listening to Tova O'Brien's guest this past week as she described the experiences of staying in motel emergency accommodation with a young daughter. From my relative privilege (of choosing the right parents and having things turn out ok for me so far), I find it hard to imagine being in this situation. But it's the reality for nearly 6,500 people across Aotearoa, half of whom are children. 
This is an emergency, and the problem is complex. The solution will require more than simply building more houses because the underlying issues are more complex than that.

Related to this is a proposal from the Ministry of Business Innovation and Employment (MBIE) to review the building consent process in New Zealand. This is something I'd like to look at in more detail because we must get the balance right.

In 2023, MBIE sought public submissions in response to an options paper on a review of the building consent system. This week MBIE published a summary of the 270 submissions received.
At the other end of the spectrum, I caught up with Jonathan Holmes about living in a Certified Passive House Premium home and working on assessing the embodied carbon in our buildings. 

Other links for this week's podcast episode:

Jonathan Holmes on LinkedIn Holmes House, Sustainable Engineering Hawea Flat, Home Style Green
Be sure to register for Reimagine Buildings '24