About
The reference directory for double glazing in Aotearoa
Plain-English, NZ-specific guidance on retrofit and full-frame double glazing — calibrated to H1 climate zones, WANZ standards, and MBIE acoustic ratings — alongside a vetted directory of the installers doing the work properly.
Why this exists
The majority of NZ homes are still single-glazed. The retrofit and full-frame markets are mature, but buyer-side information remains overwhelmingly produced by installers — making the answer to every question predictably self-serving. This directory exists to be the editorial second opinion: which kind of double glazing fits what kind of house under H1 climate zone requirements, what it costs in real NZ conditions, and which installers in each region do the work to specification.
Listing standards
Every installer in the directory is GBI-registered (Glass & Glazing Building Institute), aligned with WANZ (Window Association of New Zealand) standards, trading five years or more, and free of unresolved trade-association complaints. Acoustic claims are cross-checked against MBIE Rw ratings. Listings are reviewed quarterly and removed when standards lapse or sustained customer complaints emerge.
Editorial team
Editorial team based in Aotearoa. Listings, regional briefs, and the field guide are produced and maintained in-house. Where paid placements appear in future, they will be clearly tagged and segregated from the editorial directory.
The estimator caveat
The heat-loss savings estimator on the homepage is a single-variable thermal model calibrated to NZ H1 climate zones and typical heat-pump-warmed homes. It is a useful ballpark for a "should I bother" conversation. It is not a quote, a building-performance audit, or a guarantee. For any renovation decision, commission an installer site visit and consult the BRANZ building-performance literature.