We're swapping a big house for a better one
Bill, 4 years old, and his sister Freya, 2, are country kids. On a typical day, they bounce on the trampoline, eat broccoli and silverbeet straight from the garden, and play at moving gravel around with their toy dump truck and digger.
Lately, they also get to watch the diggers working on the very beginnings of construction on the family’s new house.
Parents Abi Huddleston, 30, and Dunstan Brook-Miller, 31, are building an energy-efficient three-bedroom home on their section in Lauder, Central Otago, but unlike the average Kiwi new build, this one is only going to be 109m².
The family also includes baby Ida, five weeks, so some might consider a large house is in order. But this couple aren’t afraid to think differently.
“We’re wanting something nice, long-lasting, healthy,” Huddleston says. “We’ve realised we don’t need a huge amount of space so we’d much rather build a better home, rather than a bigger home.”
The home will have a fully insulated slab, and the walls and ceiling will be made from Sips - or “structural insulated panels”, consisting of an insulating foam or polyurethane core sandwiched between two structural facings of strand board.
The thermal envelope also includes with triple-glazed PVC windows, and the design provides wide verandas on the north and west elevation. It will be off-grid for power.
All these features cost a little extra, but that’s a no-brainer for Huddleston and Brook-Miller, who compromised on floor space.
“We wanted to spend more on insulation and ventilation rather than spending it on more areas that I’m just going to have to clean,“Huddleston says.
She says two of the children will need to share a room, but they are not daunted. After all, the couple lived in a housetruck when Huddleston was pregnant with Bill, and the five of them are currently living in a 54m² two-bedroom shed.
Huddleston says what they have now is a “really basic set up”, but is double-glazed and warm. Being off-grid - they currently have eight solar panels and the new place will have 14 - means they don’t suffer during the frequent outages experienced in the area. They have a back-up generator.
Brook-Miller is a civil engineer working at the Clyde hydroelectric dam, and has long been interested in “all things solar and renewable energy”. He’s planning to take paternity leave to work alongside the builders where possible, and will project-manage the build.
The Central Otago climate is one of extremes, more than many realise, says Huddleston. She says in the depths of winter, it truly can be “cold and miserable”
“You’ve got a hoar frost and sometimes you don’t see the sun for 15 days.” Summer temperatures above 30 degrees are not uncommon.
Damien McGill, from the Healthy Home Cooperation, acknowledges that it’s a challenge to engineer a healthy high-performance home in such a harsh climate at 330m above sea level.
He says the challenge can be overcome with energy modelling.
“The initial results were slightly disappointing,” he says, “but by redesigning the windows so they were full height, removing one of the low-e coatings on the triple glazed PVC windows and reducing the width of the veranda, we were able to provide Abi and Dunstan a home that is 4.2 times more energy efficient than a house built nearby to current building requirements.”
He says they also checked that it won’t over-heat. As this house is completely off-grid, it was important to reduce the requirement for energy use, says Damien. For heating, in-slab hydronic heating has been used, rather than a log burner, as fires in an airtight building are problematic, from an air quality point perspective, both inside and outside, he says.
He says the Maxraft insulated foundation and use of structural insulated panels will provide “a strong, resilient, highly insulated structure”.
Huddleston and Brook-Miller met on Onward Bound in 2016 and moved to Central Otago the next year.
“We’re both pretty normal, I think,” Huddleston says, “but we do like try to live as sustainably as possible, as eco-conscious as possible. And really trying to instil that idea of looking after everything in our children.
“We look out every now and then and think the childhood they have now is exactly what we envisioned and we’re going to keep it at all costs.”
Project participants
• Structural insulated panels: NZSIP, Architectural designer: Adrian Taylor; Cadence Architectural Design, Energy modelling and Engineering: Damien McGill, The Healthy Home Cooperation, Foundation supplier: MaxRaft, PVC windows and doors: Starke, Mechanical ventilation: Condensation Control