High performance passive house built with precision
Prospective homeowners with an interest in ultralow energy new home options got a chance to view Canterbury’s first certified passive home at a public open day in May.
This well-attended day showcased one of the latest industry-leading homes in the ever growing stable of high performers within the Superhome Movement.
Owners Andrew and Katy Marriott moved to Christchurch after the Canterbury earthquakes and decided they wanted their new home to be a low-energy ‘Passive House’, which they designed in conjunction with Auckland architectural practice Brewer Davidson.
Passive house technologies originate from Germany and Andrew and Katy’s home has been certified to the international passive house standard.
Their airtight and energy efficient home incorporates triple-glazed windows, extra thick walls, high level insulation and other cutting edge technologies.
The couple interviewed six builders before choosing Glenn Harley, of Harley Bu ilders to build their home.
His team’s skill and commitment was evident to all those who attended the May open day.
“Glenn had a very ‘can do’ attitude,” explain Andrew and Katy.
“[He] was proactive by saying ‘this is going to work’ or ‘I think there is a better way we can do this’.
“So there was no rework as Glenn and his foreman John – who was excellent – saw the problems before they arose.”
While this is the first certified passive house built by Harley Builders, Glenn and his team have been building energy efficient homes in Canterbury for the past decade.
As Glenn observes, while there are still only 11 passive houses in New Zealand, this technique has been used in Germany for the past 30 years and is proving increasingly influential.
“This is the direction we have been moving in, building wider walls, in-slab heating and thicker insulation,” Glenn says.
With built-in air tightness, Andrew and Katy’s passive house is draught free and maintains a very even and comfortable inside temperature of 20 to 25degC.
In the winter months, no radiators or underfloor heating are required, so power savings in heating alone are considerable.
Fitted with solar panels and inverter, any excess power is sold back to the grid.
Blown in insulation was used in wide wall cavities to fill up every possible gap and space.
Compared to a standard new home with air leakages of 6-10 air changes per hour, their home has only 0.38 air changes per hour.
“It has really good windows and a really good wall system. Solar gain is maximised through the positioning of windows and doors.
“Simon Gibbon, of Pro Clima [a Germany company that provides airtight and windtight building solutions] was extremely helpful.
“The ventilation system, which has a heat exchanger in it, is from Germany too, as are the triple glazed windows.
Vigorous testing was conducted to ensure the home met the International Certified Passive House standard.
Aesthetics and good design have not been sacrificed to achieve high performance.
Katy and Andrew’s house is also a beautifully modern, spacious open plan family home.
Harley Builders’ exceptional work on this home was rewarded with a silver medal and a Sustainable Lifestyle Award at the 2016 Registered Master Builders’ House of the Year Competition.