Their subsequent efforts to find an energy-efficient home have turned them into trailblazers for a concept untouched so far in Australasia. The 300 square metre house they are having built in Glendowie will be the first “passive house” in New Zealand and Australia, taking architects, building suppliers, the Auckland Council consents team, not to mention the builders, on to a new learning curve.
“We are using a smart, good builder who is learning new things,” says Philip. “This is not rocket science. The suppliers have shared knowledge and the builders have put it all together. We haven’t had to back-track on anything yet.
“It has been an opportunity to raise the bar,” he says. “We’re doing this for ourselves, but we’re having it [the house] built to a new standard.”
The term “passive house” refers to a voluntary standard for energy efficiency in a building. It [the standard] doesn’t require adding additional elements to the design. Rather it’s an integral part of the design which results in little energy being needed for space heating or cooling.
The first Passivhaus (German for passive house) residences were built in Germany in 1990. Since then thousands have been built in Europe and the USA but none, so far, in New Zealand or Australia.
Philip is an engineer and his wife Carolyn is a nurse. After they experienced damp in a rented house they decided to find more environmentally-friendly principles they could inject into a house they wanted to build.
Philip did some research, discovered the “passive house” concept “and I put two and two together.
“I had nothing to do with passive houses before but I wanted something well designed. I got on to the passive kick and then had to educate Auckland Council about it.”
He says the council was “incredibly supportive”, along with building supplies company Carters, Jessop Architects and local builder Chris Foley and his team.
Insulation around the entire structure is key to the design. The house is wrapped up tightly in an envelope. Air barriers, sealing of every construction joint and all areas where service parts penetrate are used to make the structure airtight.
To eliminate the risk, super-high-density extruded polystyrene, imported from Canada, is installed around the footings and foundations and under the concrete flooring.
An air-tight barrier material, dubbed an intelligent membrane, imported from Germany, is wrapped around the house like an envelope. It breathes, letting moisture out but no outside air in. The house, Philip says, will be water-tight because if air can’t get in, nor can water. In order that the inhabitants don’t suffocate from the lack of air, a heat exchanger, which retains the heat and changes the air more than six times an hour, will be installed.
A home ventilation system is a key component of the passive house.
It provides clean, pollen-free, dust-free air and eliminates moisture and odours.
Inside the heat exchanger, heat from the warm exhaust air is passed on to the cold fresh air.
More than 90 per cent of the heat from the exhaust air can be passed on bringing the incoming air almost up to room temperature.
“We will be able to heat this house on $25 a month,” Philip says. “And it will be healthy from an air quality standpoint.
Because the house is sealed, the Ivaniers have imported a Belgian wood burner with the flue, which is normally open from the combustion chamber to the outside elements, segmented off in a separate duct. Currently no fireplaces available in New Zealand fit the “passive house” standard.
With the addition of solar panels on the roof Philip is hopeful of putting some power back into the national grid.
To avoid too much sun exposure, shutters will be installed on the north-facing doors and windows, “otherwise we would roast in the house. It’s about managing the elements”.
Incorporating passive elements does not restrict the house design, Philip says.
“You can design whatever you want. It will be easier for the next group of people who build these houses because more of the materials will be available locally and the next one will be better than the first one. But someone has to put a foot forward.”
Carolyn is horrified at reports that say lack of insulation and damp in New Zealand houses is attributed to a high rate of children’s asthma and hospital admissions for pneumonia, while many children end up with life-long respiratory problems.
“There is a high health and financial impact because their houses are not climate-controlled. Who wouldn’t want that [healthy houses] for their family,” she asks?
If Housing New Zealand was to build to 70 per cent of the passive house standard, Philip says families wouldn’t have to spend money on heating, “and these are the people who are susceptible to poor health. If we have healthier kids we have less sick days, less money spent on welfare benefits and less struggle for parents having to decide whether to feed their kids or pay the electric bills.”
Auckland Council's urban design champion, Ludo Campbell-Reid, supports the project, saying they are leading the way for a new form of environmentally sustainable, high-quality home that is cheap to run.
"As a council we are looking forward to seeing the results and want to empower people to be able to do things that will improve housing."
Wrapping a “passive house” in an envelope of insulation with heat or cooling exchanger technology produces the following advantages:
• The air is fresh and clean.
• Because hot air can not escape, the outside walls are not colder than internal walls.
• Inside temperatures are the same throughout. Single rooms, such as bedrooms, are the same as the rest of the house.
• Internal temperature changes are slow.
• Opening windows or doors does not change internal temperatures drastically. Once they are closed the air quickly returns to “normal” temperature.
• Using the sun to heat and lighten the house naturally saves energy costs and provides a healthy environment.