Hamilton's older villas and 1960s-90s aluminium-joinery homes are among the coldest housing stock in the Waikato, and windows are usually the weakest link. We've independently researched and verified the double glazing installers genuinely operating in Hamilton, checking business registration, Google reviews, WGANZ membership and real installation evidence, so you can hire with confidence.
This page highlights the Top 5 double glazing installers in Hamilton, based on independent research into reputation, accreditation, service quality and overall reliability.
The top 5 double glazing installers in Hamilton are 1. CM Glass, 2. Glasswise (RetroGlaze Hamilton & Waikato), 3. The Double Glazing Company (Waikato), 4. NZWindows Waikato, 5. RetroFit Double Glazing (Metro Performance Glass). Below we explain why each made the list, compare them at a glance, and share how to choose.
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CM Glass is the only company that manufactures its insulated glass units on-site in Hamilton, giving it direct control over quality and turnaround. It's a current WGANZ member and holds a strong Google rating built over more than 30 years trading from its Te Rapa premises.
Glasswise is the locally owned RetroGlaze licensee for Hamilton and Waikato, run by owner-operator Paul, a trade-qualified glazier operating from Pukete since 2007. It carries a strong independent review record and pairs the established RetroGlaze retrofit system with general glazing work.
Operating in Hamilton since 2004 under its own separately registered Waikato entity (The Double Glazing Company (Waikato) Limited), this is a locally run branch of an established regional network rather than a lead-generation reseller, offering both retrofit and full replacement glazing.
NZWindows has manufactured Vantage aluminium joinery in Hamilton since 1990 and is one of New Zealand's longest-standing WGANZ members (20+ years). Its Burbush branch handles everything from single window replacements to full-house re-joinery, backed by significant manufacturing scale in the Waikato.
RetroFit Double Glazing is the retrofit division of Metro Performance Glass, New Zealand's largest glass processor, and operates a genuine Hamilton showroom through Metro Direct. Units carry a 10-year manufacturer warranty and are locally processed, giving strong backing for retrofit work specifically.
A quick comparison of our Top 5 picks. Select up to 3 businesses above to compare their strengths side by side.
| Double Glazing Installer | Best for |
|---|---|
| CM Glass | Custom-manufactured double glazed units, both full frame and retrofit |
| Glasswise (RetroGlaze Hamilton & Waikato) | Retrofit/secondary double glazing into existing aluminium and timber frames |
| The Double Glazing Company (Waikato) | Homeowners wanting a choice between retrofit and full replacement from one local branch |
| NZWindows Waikato | Full frame replacement and large-scale re-joinery projects |
| RetroFit Double Glazing (Metro Performance Glass) | Retrofit double glazing backed by a major NZ glass manufacturer's warranty |
Independent, editorial, and reviewed regularly.
TopChoice rankings are editorially curated by our New Zealand team and reviewed periodically. We don't host our own reviews. Our shortlists draw on public reputation signals from Google and other platforms, alongside our own research into each double glazing installer. We weigh up a combination of:
We don't accept payment in exchange for a place in the Top 5. Featured placements are separate and always clearly labelled. Rankings may change over time as businesses evolve.
Under NZS Building Code Clause H1, new and replacement windows in Hamilton (climate zone 2) must now achieve a minimum R-value of R0.46, up from R0.37 before May 2023. That's still well below typical wall or roof insulation levels, which is why single-glazed windows remain the weakest thermal point in most older Hamilton homes, particularly the villas and 1960s-90s aluminium-joinery stock common around the city. Look for an installer who can explain how their glazing performs against this standard, and who works to NZS 4223, the relevant glazing standard covering glass selection (Part 1) and human-impact safety for glazing within 2000mm of floor level (Part 3).
There are two genuinely different ways to add double glazing to an existing Hamilton home: full frame replacement, where the entire window and frame are replaced with new double-glazed aluminium or timber joinery, or retrofit/secondary glazing, where a sealed double-glazed unit (or a magnetic secondary panel, as used by established systems like RetroFit Double Glazing and Magnetite) is fitted into your existing frame. Retrofit is typically faster and cheaper and suits sound frames in good condition; full replacement suits homes needing new joinery anyway. Worth noting: unlike insulation and heat pumps, double glazing is not funded under EECA's Warmer Kiwi Homes grant scheme, so budget for the full cost and get several like-for-like quotes. WGANZ membership (the Window & Glass Association of New Zealand) is a useful credential to check, since it signals ongoing industry standards engagement rather than a one-off installer.
Costs vary widely depending on whether you choose retrofit or full frame replacement, the number and size of windows, and the frame material. Retrofit double glazing into existing aluminium or timber frames is generally the more affordable option per window compared with full replacement joinery. Get quotes from at least two or three Hamilton installers, as pricing differs significantly between providers and glazing systems.
No. Unlike ceiling and underfloor insulation or heat pumps, which can be funded through EECA's Warmer Kiwi Homes grant for eligible households, double glazing and window glazing are not covered by that scheme. You'll need to budget for double glazing as a full out-of-pocket cost, though some installers offer payment plans.
Full frame replacement removes your existing window and frame entirely and installs new double-glazed aluminium or timber joinery. Retrofit (or secondary) glazing fits a sealed double-glazed unit, or in some systems a magnetic secondary glazing panel, into your existing frame without replacing it. Retrofit is usually quicker and less disruptive and works well if your existing frames are sound; full replacement makes more sense if frames are damaged, rotten, or you're renovating anyway.
A straightforward retrofit job on a standard Hamilton home can often be completed in one to a few days, depending on the number of windows. Full frame replacement projects, especially whole-house re-joinery, take longer and may run to one to two weeks depending on scope and any consenting requirements.
Generally yes. Many of Hamilton's older villas and character homes were built long before double glazing was standard, and windows are typically the weakest thermal element in the house under current Building Code H1 standards. Retrofit systems in particular let you add double glazing without disturbing original joinery, improving warmth, reducing condensation and cutting noise while keeping the home's character.
Editorial disclosure: TopChoice is an independent editorial platform. Some pages may include clearly labelled featured placements for additional visibility. Featured placements do not influence rankings within our Top 5 lists.
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