Sustainability lies at the heart of Whakatū Passivhaus — an impressive project which became both Nelson’s first passive house and the country’s first home to achieve a 10 Homestar built rating under version 5 of the Homestar framework. The homeowners, project architect Nathan Edmondston and partner Yuki Fukuda, wanted to create a home that would have minimum impact on the environment by taking care to ensure low carbon, minimum waste on site, and minimum reliance on energy. Through careful design choices — including specifying locally sourced Macrocarpa cladding from HTL — they were able to meet their objective to live lightly on the land. 

“The clients wanted to have as little impact on the land as possible,” says Lenny Basham, Builder and Owner of Basham Building. “They are passionate about the environment and really in tune with their carbon footprint, so the passive house was a nice fit for them as it's a standard that measures energy consumption.” 

The home incorporates a number of materials that contribute to both high performance and low ongoing carbon including triple glazed windows, well considered insulation and minimal use of concrete. Local materials were sourced from the Nelson/Tasman region wherever possible to further minimise the carbon footprint of the home. 

For the exterior, the clients wanted a natural timber cladding that over time could blend into the natural landscape of the section which they’ve planted with native trees. HTL's KiwiTEC Macrocarpa cladding met this brief, and as a locally sourced material, was ideal for the carbon-conscious project. 

“Where we could, our clients wanted to source materials from within a 150k radius, so being able to source the cladding locally was a big positive,” says Lenny. “Macrocarpa was chosen because it looks nice, it met the client's budget and they had availability during the Covid era. It was just a win on all fronts really.” 

HTL KiwiTEC Macrocarpa cladding is made from durable and sustainable NZ Macrocarpa — which is grown in the Tasman region, milled from log to timber by HTL at their sawmill, and machined into cladding by HTL in Nelson less than 20km away from the home. The cladding was factory coated by HTL with its first coat of DRYDEN WoodOil to maximise the cladding’s structural integrity and visual appeal over time.

Installation of the cladding was straightforward for the Basham Building team. “HTL supplied us with all of the profiles, and we incorporated those into the design so we weren’t having to get anything specifically custom made,” says Lenny. “It was a pretty easy process. The good relationship between designer, builder and supplier, helped us to achieve a good result.” 

The HTL KiwiTEC Macrocarpa cladding also contributed towards the home’s Homestar rating. “Part of that came down to cladding choice,” says Lenny. “Using a natural product that’s really low in carbon and is sourced locally helped us achieve a Homestar green rating of 10. I think if we had chosen something else that met budget we may not have achieved that rating.”

The finished home showcases the warm tone and texture of the HTL KiwiTEC Macrocarpa cladding, with the timber set to ground the home into its landscape as the native trees come up over the years. “The clients seem really really happy with it,” says Lenny. “And I think in time, once they grow their native trees, the soft natural look of the timber will come into its own.” 

And importantly, the home has met the clients’ goal of a low carbon passive house that offers year-round comfort. “We’re really pleased with how it performs,” says Lenny. “What we set out to achieve on paper has been exceeded by what's on site. We’ve got really low energy bills. It's a pretty amazing feeling when you open the door and walk into the house.”