Expert Interview: Mark Anderson on the Future of Passive House Design

We caught up with Mark Anderson from MA Building Wanaka to dive into the world of Passive House design — what it means, why it matters, and how it’s shaping the future of building in New Zealand. With a passion for building for future generations, Mark shares valuable insights into the process, challenges, and rewards of building homes that are both energy-efficient and beautifully crafted.

1. Can you explain the core principles of Passive House design and how they influence your building projects?

At M A Building, we focus on building homes that adopt the key passive house principle, so our homes are airtight, highly insulated, and free from thermal bridges, meaning there are no weak spots where heat can escape. We use high-performance windows and mechanical ventilation systems to keep the indoor environment comfortable and healthy while minimising energy use. Our approach is all about making high-performance building accessible, which is why we’ve developed three performance tiers to suit different budgets and goals. We also integrate thermal modeling right from the start, so we know exactly how a home will perform throughout the year, before we even break ground.

2. What motivated M A Building to specialise in Passive House construction in Wanaka, and how does this align with the region's sustainability goals?

For me, the journey toward Passive House construction started with making healthier choices for my family. As we focused on well-being, it became clear that our homes should support that too, warm, dry, and energy-efficient instead of the cold, drafty houses so common in New Zealand. Building doesn’t have to be that way, and I’m passionate about creating better homes that promote health and comfort for future generations. Passive House isn’t just about efficiency; it’s about building homes that genuinely improve quality of life while helping move New Zealand toward a healthier, more sustainable future.

3. Could you walk us through your process of achieving Passive House certification for a project, from initial design to final assessment?

Sure. The process typically starts with either a Passive House-certified architect or an architect working closely with a Passive House advisor. From the very beginning, we make sure the design is meeting the criteria, it needs to be thermally modelled to ensure it's on the right track.

When it comes to components, we have to use certified Passive House-rated products, windows are a good example of that. As a builder, it’s not just about following the design and plans, we also have to stick to the exact specifications, product selections, and procurement. Everything needs to be documented and photographed properly.

Some elements require extra documentation too, for example, subcontractors might need to provide specific data, like flow rates for the ventilation system. The Passive House certifier will carry out inspections throughout the build to make sure everything is being done right, with the correct products and at the required standard of quality.

One of the key milestones is the blower door test, we need to achieve an airtightness result of 0.65 air changes per hour or lower. All the information we gather, from pre-build planning through to construction, gets collated and sent off to an independent third party for verification. That’s what ultimately gets us the certification.

4. What are some of the unique challenges you face when constructing Passive Houses in Wanaka's climate, and how do you address them?

We see all weather here in Wanaka, our summers are hot, our winters are freezing, and we often see four seasons in a day. All this makes maintaining a stable, comfortable indoor temperature a real challenge, which is why Passive House principles are so crucial. By focusing on airtight construction, high-performance insulation, quality windows, and mechanical ventilation with heat recovery, we minimise the impact of these extreme shifts.

5. What role does collaboration with architects, designers, and clients play in successfully implementing Passive House standards in your projects?

We love collaboration here, we believe it’s key to a successful Passive House project and we love being part of the process. Sharing ideas and drawing from each person’s experience strengthens the overall design and end result, every project benefits from the unique skills and insights of the team. A strong team will always achieve more, and we love working closely with architects, designers, and clients at every stage. Building these relationships with like-minded professionals not only improves each home but also helps push the industry forward.

6. How do you ensure that the materials and construction methods used in Passive House projects are both sustainable and suitable for the environment?

A lot of the time, we don’t have the final say, clients and architects usually have the specifications locked in. That said, we do have preferred products, like Terra Lana, that we’ll push for where we can because we know they perform well for various reasons.

One thing we’ve learned over time is that not all products work the same in this environment. You can have two materials that technically do the same job, but they’ll perform very differently in practice.

Sustainability is an interesting word. For me, it’s not just about how a product is made—it’s about how long it will last.

A product might have a great manufacturing process, but if it doesn’t hold up over time, is it really sustainable? I think a better way to look at it is to choose materials that are sourced responsibly and can withstand the local climate for as long as possible.

Take timber, for example, it has to be fit for purpose. If a material fails and needs to be removed and replaced, that’s not sustainable. So, for us, sustainability isn’t just about sourcing, it’s about longevity and making sure what we build lasts.

7. Do you have a favourite project, and why?

It’s hard to pick just one favourite because every project brings something unique. Our recently completed Passive House was a standout, the build had to be incredibly airtight and well-insulated to handle Wanaka’s extreme climate, which brought its own challenges on site. Another highlight was a high-performance home where we focused on precision and detailing to maximize energy efficiency while working within the client’s budget. Every project is a chance to learn and refine our craft, collaborate with great teams, and show how better building can work for different needs and budgets.

8. What are the long-term benefits of investing in a Passive House, both environmentally and economically?

The long-term benefits of a Passive House are huge, lower energy bills, a healthier living environment, and a home that’s better built for our kids. Because these homes require so little heating and cooling, you’re protected from rising energy costs while also reducing your carbon footprint. Beyond the numbers, it’s about comfort, no cold drafts, no overheating in summer, just a home that stays at the right temperature year-round.

9. Looking ahead, how does M A Building plan to further promote and expand the adoption of Passive House standards in the Wanaka community?

Education and advocacy are a big part of what we do at M A Building. Through local events, podcasts, and collaborations, I want to help shift the construction industry towards more sustainable practices and better building outcomes. It’s not just about building better homes, it’s about improving living standards, supporting mental health in the trades, and showing that there’s a smarter way forward for our industry.

A couple of key pillars for us: we won’t build below our Tier One energy level, and every house we construct will be thermally modelled. We’ve made the decision that we’ll never build a 'code minimum' house again. It’s about setting a higher standard and making sure every home we build is efficient, comfortable, and truly built for the future.

"I’m passionate about creating better homes that promote health and comfort for future generations. Passive House isn’t just about efficiency; it’s about building homes that genuinely improve quality of life while helping move New Zealand toward a healthier, more sustainable future."

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PROJECT CREDITS

Mark Anderson, MA Building
For more information visit https://www.mabuilding.co.nz