Browne Residence Cambridge
Architecture & Passive House Design Architype NZ –architype.co.nz
Construction Ehaus / Brown Construction www.
Certifier Sustainable Engineering Ltd – www.sustainableengineering.co.nz
This certified passive house project was designed and built for a couple relocating to the Cambridge. They wanted to build a comfortable, energy efficient house that would suit their needs as they aged. This was Architype’s first passive house project in the North Island and given the relatively mild weather in the Waikato they wanted to try to stick to a very simple recipe to achieve the PH standard. After modelling various options in the passivhaus planning package, they found that the standard would be achieveable with simple structural insulated wall panels, good quality timber framed windows with double glazing, and a simple albeit carefully modeled insulated slab.
The building itself is located on a corner site of a relatively busy street in central Cambridge. The site is a long narrow triangle which runs parallel to the road to the south. The district plan rules required a large setback from the road which meant that almost the entire site could not be built on as of right. Architype’s response was to locate the building parallel to the southern street boundary, partly within the street setback. This created a strong edge to the street and open up space to the north for private outdoor living space. By layering up the building and landscaping using strong horizontal elements the visual impact of the house on the street was minimized. The wide eaves also provide excellent shading from high summer sun and reduce the frequency of overheating. From a layout point of view the program for the house is relatively straight forward. The bottom level of the house contains the master bedroom and all spaces required for the couple’s day to day needs. The upper level contains 3 guest bedrooms for visiting family & friends.
Due to the importance of building services, mechanical ventilation and airtightness in passive houses, the building was designed from the outset with the achieving high levels of airtightness and distribution of 90mm dia air ducts in mind. The layout, structure, services and aesthetics of the building work tightly together to create a simple yet extremely high performance building.
Passive House Metrics
- Heating Demand 14.7 kWh/m2/year
- Heating Load13.3 W/m2
- Frequency of Overheating0%
- TFA 207.6 m2
- Form Factor 3.1
- Air leakage @ 50Pa0.3 ACH/hour
- PER demand42 kWh/m2/year
Construction Details Average Values
- U-value External Walls 0.26 W/(m2K)
- 115mm NZSIPs
- U-value Floor0.23 W/(m2K)
- Max Raft floor
- U-value Roof 0.15 W/(m2K)
- 300mm Batts in roof
- U-value Glass1.12 W/(m2K)
- PlaniTherm XN
- U-Windows1.34 W/(m2K)
- Ventilation Efficiency 85.61%
- Zehnder Q350