Engineer Nick Gaites made a commitment to Passive House design several years ago, and he wanted to prove a point – certified Passive House architecture doesn’t have to be conservative, or look like a box. And it doesn’t have to be big.
Gaites of Reveal Building Consultants, set out to design and build a house for his own family at Waimauku, west of Auckland – a house that would look a lot different architecturally from every other Passive House.
“There are a lot of Passive Houses that are quite staid in their architecture,” he says. “And that comes from a technical and engineering basis – the building science aspect that makes you want to achieve excellence when it comes to energy balance. People are very focussed on minimising thermal bridges, and achieving as low as possible [score for] heating demand.
“I think that leads people to design houses that are very conservative – a box. And it’s true, the most efficient shape in terms of external surface area (roofs, walls, floor) to internal volume, is a two-storey house – a box. Actually, it’s a sphere, but we don’t build houses as spheres.
“So you get these houses that are two-storey square boxes with small windows and relatively staid architecture. I was aware there was a perception by the public that this is how they had to be – airtight boxes where you couldn’t open a window, and you were living in a sealed box.”
Gaites says he wanted to “smash” that perception by showing what a passive house can be, even though it meant compromising the heating demand figures.
“We are right at the top in terms of heating demand, but in practice that doesn’t mean a lot, because we have hardly put any heat into this house over the winter. It’s worked extremely well. The temperature stays around 21.3 deg C, and it rarely varies as there is very little leakage. And we have a lot of glass, which is high-performance triple-glazed, although that isn’t strictly necessary in Auckland.”
Gaites says that, at 233m², his four-bedoom family home is not large by executive standards, but it seems a lot larger due to the soaring ceiling in the main living area, open-plan layout and high clerestory windows. “It’s an illusion,” he says. One that’s helped by the way the spaces flow from one to the other – the boys’ bedrooms come off a spacious gallery area that opens to the outdoors. And the entry is straight into the main living space.
On the exterior, the asymmetrical roof soars in one direction, and in the other it wraps down the house to form a wall – the architectural feature is reproduced on a much smaller scale beside the garage.
And Gaites is keen to point out, the family does have doors and windows open in summer, and they don’t worry about the mechanical ventilation – they just leave it running. “With everything open, it goes into a bypass mode, so it’s not doing heat recovery,” he says. “It’s just an ordinary house, and you live in it as you will.
“But, in the winter when you want to have the windows and doors shut because it’s rainy, windy and horrible, you’ve got fresh-air ventilation in all the rooms. Really, it’s a lot about our winter conditions. That’s the time when mould generates in houses, when people’s asthma is playing up, and illnesses happen, because we do keep our houses shut up.
“The building code allowing opening windows to be the sole means of ventilating a house is a problem. In a non-Passive House, you can’t control how much or how little ventilation you get; if it’s raining you can’t have the windows open; and you can’t control your CO2 levels in bedrooms. I suspect this will be addressed in the not-too-distant future with legislation.”
Retrofitting houses to EnerPHit and even full Passive House design has long been an interest for Gaites, and something he is likely to be working on quite soon. Because now he has realised the dream Passive House for his own family, he is selling up.
The reason? Gaites says it was never in the plan to sell at this time, but the design-and-build process took a very long time due to unforeseen events. These included the collapse of a developer’s plans for this house on a different site, a joinery firm going under (taking a lot of his money with them), and last, but not least, the Covid lockdowns.
In the meantime, Gaites’ two young sons Isaac and Finloe have become serious (international) sailors, and they need to be closer to the Murray’s Bay Yacht Club, so the family is moving from Waimauku. Gaites’ wife Heather has taken a job in Takapuna, so she can drop the boys to school in Murrays Bay.
Gaites has the experience to retrofit houses to Passive House standard. His company rebuilds a lot of leaky homes – around five a year. And he sees retrofits as essential long-term, due to our huge housing stock, and the number of new homes being built to a basic standard.
“New houses that are not being built to a high-energy standard are problematic, because the energy consumption of those buildings is locked in for 50 years. You are actually constantly compounding the problem.”
Gaites says recladding existing leaky homes offers an opportunity to make them airtight and energy efficient at the same time. “Then you’ve solved the health problem and the building problem.”
But he says there is another issue with leaky home retrofits – the cost. With owners already paying out hundreds of thousands of dollars, in some cases, simply to rebuild their homes to a basic standard, it is a big decision to add what could be another $100k to the bill to bring them close to Passive House standards.
Gaites would like to see the government introduce a new scheme with a view to reducing the operational carbon consumption of the building stock by both helping people to reclad their buildings, and also achieve an energy-efficient status.
And the upside is, there will be minimal, if any, heating bills from that point on. “If you actually heated a building code-minimum house to the same level as a Passive House (with no heating), you’d probably have a 1kW heater going in every room all the time. And that’s massive.
“You also have the ability with a Passive House or refit to add modern energy-efficient heating systems, like air-to-water heat pumps for hot water and heating, and solar PV, which we have here. That is also useful when we have power outages.”
The property, on 7980m², includes an additional building with an office and garaging. It is for sale by negotiation through Barfoot & Thompson.
© 2023 Stuff Limited
