Passive house @ Number 7
A difficult section to build on
@ Number 7 was specifically designed to meet the challenges of a difficult site in a harsh environment.
With a 3 mtr height difference between the drive way entry and the back of the section the land was a swamp. In order to capture this mountain views this is where we wanted to build our passive house. So 3 years prior to building we created two retention ponds to capture the water and dry out the building platform at the back of the section.. The ponds were successful in drying out the land and now make a beautiful feature of the landscape with Mt Ruapehu as the backdrop.
Building convenants
While the land was drying out, we moved on to the design of the property, that would meet the criteria of the covenants of this piece of land. Any building had to be at least 4 m from the drip line of any protected NZ native beech tree, as well as 20 m from the stream. The maximum height of the building could not exceed 7 meters. Furthermore, the normal boundary rules that stipulate that no building can be built within 20 m of any boundary needed to be taken into consideration as well..
The final objective was to achieve the best possible mountain view while working within all the restrictions and the building envelope restrictions of a passive house.
Horopito's climate is tough
Having lived in Horopito since 2013 we know that the winters can be bitterly cold.
Located at 850 m above sea level and close to the volcanic plateau with Mt Ruapehu dominating the landscape, our priority was to be warm in the winter without having to reply on firewood and /or expensive heating bills.
Fringed by protected native bush with 30mtr tall beech trees around us, the winters don't provide a lot of sunshine. The trees block the low rising and early setting of the sun during the harshest period in the winter. Rain, snow, cold high winds from the mountain and low temperatures are the norm in winter. This strengthened our wish to create a home that was going to be warm, and energy efficient.
A passive house was born
After the plans were drawn up according to our own design, a certified Passive House Consultant was engaged to model the house design based on the climatic conditions and to meet our brief of having the house passively heated to 21 degrees throughout the year.
With the modelling complete the design was finalised to incorporate the specific insulation requirements. This included 60 cm polystyrene /concrete foundations, 30 cm thick walls, 50 cm insulation in the ceiling and the highest quality triple glazed windows that could only be sourced from Germany.
Despite the challenging site we managed to achieve all our objectives and the building passed the airtightness test to meet passive house standards.
