House of a lifetime

Laughter erupts when the Baillie family discuss how long it took for their modern eco-home dream to become a reality.

Youngest daughter Maia, who’s in her first year at university, sums it up: “As long as my memories go back, Dad was planning it and fiddling around with his toy houses.”

Those ‘toy houses’ were father Russell’s models for the Baillie Eco-Home, bringing together decades of experience as a building services engineer. As he tinkered and picked up ideas, the project snowballed. It took 10 years from inception to construction, but the result is worth it: a modern-looking family home that’s deep green under the skin.

Russell, who works as the University of Auckland’s energy manager, wife Gail, and daughters Sacha and Maia, spent two years looking for the perfect site: close to schools, shops and public transport, with excellent orientation for sun.

The house in the Auckland suburb of Mt Eden runs on an east-west axis, so living areas and bedrooms get sun all day long. Concrete floors and internal walls soak up that warmth and release it as the temperature drops outside. The window shades of the 157sqm, five-bedroom house are designed for all seasons.

“At solar noon on the longest day of the year, there’s zero sun in the house. The further into winter and the lower the sun angle, the deeper the sun penetrates into the house,” Russell explains. They insulated the home to almost twice what the Building Code requires.

“Meeting the Building Code is being as cheap and nasty as you are legally allowed to get away with. It definitely doesn’t represent good practice.”

He’s particularly enthusiastic about their heat recovery ventilation unit. It extracts moist, warm air from kitchens, bathrooms and living spaces and uses it to warm up the fresh outside air being drawn in.

“That’s the heart of a healthy home,” he says. “If I was a dictator in charge of Housing New Zealand, I’d get one of these for every state house.”

Shorts and t-shirts are worn inside all year round. Russell describes how, one frosty winter morning, the closest NIWA monitoring station measured 0.2C, but it was 17.5C inside the house. Heating was installed during construction but hasn’t been turned on since they moved in at Christmas 2016. As a net zero energy house, this home produces as much electricity as it consumes over a 12-month period.

There are 20 solar panels on the roof, and a Tesla Powerwall battery stores unused energy. During summer, they sell electricity back to the grid, though Russell says, “It’s not something you’d do for a financial return; it’s a belief-system thing, or for geeky engineers.” Like any self-respecting eco-home in the 21st century, the house has its own Facebook page (search for Baillie Eco-Home). Russell publishes data from temperature sensors and energy monitors, and information about the house, as a public learning resource. Maia laughs, “I got outed on the public Facebook page for having long showers!”

Sacha and Gail love sitting in the hanging chair in the house’s front corner, basking in the sun and reading. Up the stairs, made from chunky mataī salvaged from a Wairarapa gully, two green roofs are visible.

“So much of the city is tarsealed over. We need to bring back more space for the butterflies, bees and invertebrates,” Russell says.

Gail took a landscape design course in order to create the garden, a beautiful mixture of native trees, bushes, flaxes and food. The lawn is a grass endemic to the Auckland volcanic field. Pears and apples are espallieried to make the most of a small space; hanging pockets for a green wall hide the compost bins.

“Almost all our plants are native or food-producing,” she says.

Other eco-choices include water-efficient showers and taps, three 5000-litre rainwater collection tanks, energy-efficient appliances and low-VOC (Volatile Organic Compound) paint. The locally-made double-glazed windows use European tilt-and-turn hardware for secure ventilation.

Russell and Gail drive a Nissan Leaf, and commute to work on e-bikes. They estimate they spent, on a square-metre basis, about half the price of a typical new Remuera build – by prioritising good design and quality materials, rather than flash gadgets. Many decisions were guided by Homestar, an independent rating tool that certifies a home’s efficiency, health and sustainability.

A Homestar rating of 10 signifies a world-leading home, and Russell thinks they’re on track to hit that. Whether you go full eco or focus on doing the basics (insulation and ventilation) well, it’s vital to work with like-minded people, Russell says.

“If you get a bunch of tradies who haven’t built green and aren’t interested, they’ll end up defaulting to their usual high-toxicity glues and everything else. But if you pick tradespeople who are passionate about what you’re trying to do, collaboratively you’ll end up with a much better result.”