Passion for passive pays off
First-time homeowners manage to build a passive house on a budget. Colleen Hawkes reports.
There’s an assumption that going down the sustainable route is simply too tough for first-home owners. But the young owners of this brand-new, about-to-be certified passive house in Hillcrest, Hamilton, have proved otherwise.
They wanted their home to have a very small carbon footprint, despite the fact that were trying to bring the budget down to qualify for a Homestart grant.
It turned out it wasn’t possible to go quite that low, mainly because they were building their own house, not buying an existing property.
‘‘We did look at some existing houses in our price range, but were disappointed in them,’’ says one of the homeowners.
‘‘And we didn’t want to be in a builders’ development. We wanted to know what went into our house and build it to suit our needs.
‘‘Our interest in high-performance homes was sparked by time spent in Europe where it’s freezing outside and lovely inside. Such a contrast to the draughty, damp and cold New Zealand homes I’d always lived in.’’
The homeowner chatted to a colleague who had undertaken a recent build and quizzed her on the process.
‘‘We had found a section, but didn’t really know if it was suitable. It was cross lease, with a flat building platform that wasn’t huge, and a 6-metre drop to a forested gully.
‘‘Our colleague advised that we contact an architect to look at the section so we could get an idea of what to do and what it would cost,’’ says the owner.
‘‘I talked to architect Andrew Bydder and he suggested that we should try to get an agreement with the vendor that the contract would be conditional on getting resource consent granted for his concept plans, and that took about four months.’’
The couple had to pay for soil and stormwater studies for the consent, and their costs had racked up to $20,000, yet they still didn’t know if they would buy the land. ‘‘I was kind of muddling along the best I could,’’ the owner says.
The purchase did go through, and the owners talked to different builders as they tried to nail down a contract. In the end they went with eHaus, a passive home builder specialist.
The couple had set aside $360,000 for the build (for a three-bedroom, 100-square-metre house), on top of the $212,000 for the land, which escalated to around $230,000 with costs.
They then discovered that the original estimate
‘‘A passive house does tend to cost 20 per cent more than a conventional home, but these owners are not just building for the short term.’’ eHaus managing director Ross Brown, above
of seven piles needed to be revised. ‘‘The report came back, saying we would need 42, but our engineer managed to get it back to 11.’’
Other aesthetic costs not included in the original quote included patios for $5000 and the council services fee of $15,700.
‘‘Aluminium windows are not as suitable for a passive house so we opted for uPVC window framing, double glazed and with a dark coating that cost extra. The window framing and the patios together were an extra $12,000. All the costs added up to more than the $550,000 maximum for the Homestart grant.’’
But the house will pay off in the long term, says eHaus managing director Ross Brown. ‘‘A passive house does tend to cost 20 per cent more than a conventional home, but these owners are not just building for the short term,’’ says Brown.
‘‘In eight to 12 years they will be getting payback on their initial investment. The house will be certified to low-energy standard.’’
Brown says the level of insulation is two to three times that required by the building code. ‘‘They have also gone for quality joinery, and the whole building is airtight.
‘‘The house features a heat exchange ventilation system that replaces the air every three-and-a-half hours. The existing warmth in the house, which can be from sun, people and appliances, warms the incoming air. And the system works in reverse in the winter. We have also introduced automated roller shutters that can stop the heat building up in summer.’’
Most owners of certified passive houses don’t need to turn on a heater or fire, depending on where they live. If there are several days in winter with no sun, or if they have been away from the house for several days, they may need a short burst of heat to bring the temperature back to its normal level.
Brown says the eHaus show home is proof the system works. ‘‘I can walk into the show home when there is a frost outside, and even though there is no heating and no-one in the house, it’s 20 degrees [Celsius] inside. The heat is not going to escape.’’
The owners agree. ‘‘We visited the empty house one night just before we moved in and it was so warm, I didn’t want to leave,’’ one says.
Costs so far, including the land, are around $610,700. But now, it’s time for the family of four to move into their new house and enjoy the controlled climate through all seasons, although the owners admit their focus is shifting to landscaping.