Rodriguez emphasises the important role of Low-E coated glazing and thermal edge spacers in directly affecting the glazing U-value, as well as the overall installation detailing such as air barrier continuity, water-shedding, and placement within the rough opening.
"When designing a Passive House," Rodriguez adds, "minimising thermal bridges within the window installation is crucial. This can be achieved by correctly aligning the frame with the wall insulation."
Continuing, Diaz touches upon the issue of condensation and mould growth, common in cooler climates. "In cooler weather, the combination of cold internal aluminium window frames within the warm air of a home creates conditions conducive to mould growth in the presence of condensation.”

Kāinga Ora suggested Peddle Thorp consider aluplast, and Diaz says they found the aluplast systems presented a viable route to meet passive house criteria as well as meet New Zealand building code requirements.
Designed and manufactured to withstand Australasian climatic conditions, Diaz says the aluplast systems were required to demonstrate their proven ability to resist UV-induced degradation.

"Kāinga Ora holds onto its assets, so robustness and longevity are key besides compliance. We also needed a supplier who could provide support, and we wanted to make sure the windows would look good, and they do."

Peddle Thorp faced the challenge of harmonising New Zealand's daylight mandates with the rigorous standards of Passive Housing, which can reduce window space. Additionally, as Diaz notes, a key issue in Auckland's warm summers is the risk of overheating. "Enhancing building envelope efficiency can inadvertently trap heat, leading to excessive warmth inside," he explains. "Therefore, careful planning of window sizes, their placement, and shading solutions was crucial. We also had to account for anticipated climate changes over the next two decades."