Window Replacement Cost NZ – 2026 Auckland Guide
Quick answer: Window replacement in Auckland typically costs $400–$800 per square metre for retrofit double glazing, $2,000–$2,500 per unit for insert windows, or $2,400–$3,500 per unit for full joinery replacement — with most Auckland homeowners paying $1,500–$3,500 for a single window swap, and $25,000–$45,000 for a full house re-joinery once the gib repair, painting and architrave work are included.
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You notice it on a cold morning. Condensation on the inside of the glass. Or the bottom of the timber sash is soft when you push it. Or one of the panes has fogged up between the layers — that telltale grey haze that means the seal has gone. Suddenly you’re trying to work out whether you’re looking at a $400 fix or a $40,000 job.
The honest answer is — it depends on more variables than most homeowners realise. Window work in Auckland splits into four different methods, three different materials, and a layer of post-installation work that most installer quotes don’t include. A $18,000 quote and a $26,000 quote often aren’t pricing the same job. One’s supply-and-install only. The other includes the gib repair, painting and architrave work to make the new windows actually look finished.
This guide breaks the numbers down properly. We handle the full window job across Auckland — we’re not selling you a specific brand of joinery, we’re the company that pulls in the joiner, the builder, the painter and the gib stopper to get the job finished. So the costs you’ll see here are the all-in costs, not just the bit installers quote.
You’ll find: what the four replacement methods actually cost, how aluminium, uPVC and timber compare, the hidden costs installer quotes leave out, when you need building consent, and a repair-first decision framework — because sometimes the right answer is to fix the existing window, not replace it.
The Four Window Replacement Methods (And What Each One Actually Costs)
Before you compare quotes, you need to know which method each quote is pricing. The four options aren’t interchangeable. Each one has different cost, different disruption, different outcomes — and only some of them are right for your house.
1. Glass-only replacement: $150–$1,200 per pane
The cheapest path. You keep the existing frame and replace only the glass. Single-pane glass replacement runs $150–$400 for smaller windows, and $400–$800 for larger windows including labour and call-out. Replacing a fogged double-glazed insulated glass unit (where the seal has failed and condensation is sitting between the panes) is typically $300–$700 per unit, sometimes up to $1,200 for oversized panels.
This makes sense when: the frame is sound, the glass is broken or the IGU has failed, or you’ve had a single-pane break from impact or storm damage. It doesn’t make sense if the frame itself is rotten, the seals around the frame are gone, or you want better thermal performance — replacing just the glass in a single-pane window with new single-pane glass gives you zero improvement.
2. Retrofit double glazing: $400–$800 per m²
The Auckland character-home favourite. Retrofit double glazing means routing out the existing timber or aluminium frame, removing the old single-pane glass, and slotting a sealed double-glazed insulated glass unit into the same frame. The joinery stays. The glass and the glazing strip get replaced.
Cost runs $400–$800 per square metre installed, which works out to roughly $400–$700 per standard bedroom window or $800–$1,500 for larger living-room glazing. A full house retrofit on 12–15 windows in a Mt Eden bungalow or Devonport villa typically comes in at $8,000–$15,000 — significantly cheaper than full joinery replacement.
This is the right answer when the existing timber joinery is in good nick and worth keeping (most character homes), when you don’t want to lose the period look of the original sashes, and when you want better thermal performance without the cost or disruption of pulling the whole frame out. It’s not the right answer when the frame itself is rotting or has warped — in that case you’re throwing good money after bad.
3. Insert windows (retro-fit replacement): $2,000–$2,500 per unit
A middle option that sits between retrofit double glazing and full replacement. The existing frame stays in place, but you slide a complete new aluminium or uPVC window unit (frame and glass together) inside the existing opening. The new unit is slightly smaller than the original opening (you lose about 25–40mm of glass area on each side), but the cladding and interior trim around the window stay untouched.
Insert windows cost $2,000–$2,500 per unit installed and are common when the original aluminium joinery is at end-of-life but the surrounding cladding and gib work is fine. You get a brand-new sealed double-glazed unit without the disruption of removing all the trim.
The trade-off is the slightly reduced glass area and the fact that you’re working within the original opening size — if the original window was small and dim, your new window is going to be marginally smaller and dimmer.
4. Full joinery replacement: $2,400–$3,500 per unit
The most disruptive and most expensive option, and the most common when you’re doing serious work. The entire window (frame, glass, trim) comes out. A brand-new unit goes in. The opening size can change. The interior architrave gets replaced. The exterior cladding around the window needs to be repaired and matched.
Full joinery replacement runs $2,400–$3,500 per unit for standard sizes, with larger windows and sliding doors (ranchsliders) coming in at $4,500–$7,000 depending on size and material. A full house re-joinery in Auckland (typically 12–18 openings) works out to $25,000–$45,000 once the cladding repair, painting and gib work are included.
This is the right choice when the existing joinery is past saving (rotten timber, warped aluminium, failed seals across the whole house), when you want to change the window configuration (turn a small high window into a large picture window, or change opening direction), or when you’re doing a major renovation and the walls are already opening up.
| Method | Cost Range | Best When |
|---|---|---|
| Glass-only replacement | $150–$1,200 per pane | Broken pane, failed IGU, sound frame |
| Retrofit double glazing | $400–$800/m² | Character home, sound timber frames |
| Insert windows | $2,000–$2,500 per unit | Old aluminium joinery, intact cladding |
| Full joinery replacement | $2,400–$3,500 per unit | Joinery past saving, configuration change, full renovation |
💡 Property tip: Don’t ask installers what a window replacement costs — ask them which method they’re quoting. A $20,000 quote for retrofit double glazing and a $20,000 quote for full joinery replacement are pricing completely different jobs. The cheaper-looking quote might be the worse value if it doesn’t include the work your house actually needs.
Window Material Costs — Aluminium, uPVC and Timber Compared
Once you’ve decided on a method, the material choice is the next big cost driver. Auckland’s three options are aluminium (the workhorse), uPVC (the thermal performer) and timber (the character home staple). Each has a real place, and each has a price point that reflects what it gives you. For a deeper side-by-side, see our guide on aluminium vs uPVC vs timber windows in NZ.
Aluminium double-glazed: $800–$1,500 per m²
The default choice in modern New Zealand homes for good reason. Aluminium joinery is durable, low-maintenance, holds up well in Auckland’s salt-coastal climate, and has the slimmest sightlines of any frame material. Most aluminium joinery is built locally (by manufacturers like Fairview, FirstWindows, APL, Nulook and Vantage), which keeps lead times reasonable.
Standard double-glazed aluminium joinery runs $800–$1,500 per square metre installed. Powder-coated colour options add 5–10%. Thermally broken aluminium (with a polyamide barrier between the inside and outside of the frame, which dramatically improves thermal performance) sits at the top of the range ($1,200–$1,800/m²) and is the closest aluminium gets to uPVC’s insulation performance.
Aluminium is the right call for: modern subdivisions, coastal suburbs like Mission Bay, St Heliers and Takapuna where saltwater corrosion is a factor, anywhere you want slim sightlines and large glass areas, and any rental or investment property where low maintenance matters.
uPVC double-glazed: $900–$1,600 per m²
The thermal performance leader. uPVC (unplasticised polyvinyl chloride) frames don’t conduct heat the way aluminium does — they’re effectively insulators in their own right. In a colder Auckland winter, the difference shows up as warmer internal frame surfaces (less condensation) and a quieter house (uPVC dampens sound better than aluminium).
uPVC double-glazed windows cost $900–$1,600 per square metre installed in Auckland, with most jobs landing closer to the $1,200/m² mark. Lead times are usually 2–4 weeks longer than aluminium because more uPVC joinery is imported.
uPVC sightlines are chunkier than aluminium (the frame profile is wider), which some people don’t love aesthetically. But for cold homes, condensation problems, or anywhere thermal performance is the priority, uPVC outperforms standard aluminium by a noticeable margin.
Timber double-glazed: $1,200–$2,200 per m²
The character-home choice. Timber joinery (usually cedar, accoya or sustainably-grown pine) sits at the top of the cost range, but it’s the only material that genuinely matches the look of an Auckland villa, bungalow, or pre-1950s character home. Modern timber joinery can be specified with double glazing built in, so you don’t lose thermal performance.
Timber double-glazed joinery runs $1,200–$2,200 per square metre installed. Cedar is on the lower end of that range; accoya and high-spec hardwoods land at the upper end. Timber requires repainting every 6–10 years (especially on west-facing or coastal walls), which is an ongoing maintenance cost — though one that’s easily handled as part of routine exterior repainting through our painting services.
Timber is the right choice for: character home suburbs (Mt Eden, Ponsonby, Grey Lynn, Devonport, Herne Bay), heritage-protected properties where aluminium isn’t permitted, and anywhere the visual character of the house matters more than the maintenance schedule.
Which Material Makes Sense in Your Suburb
The right material isn’t just about cost — it’s about where you live. Three patterns we see across Auckland:
Character suburbs (Mt Eden, Ponsonby, Grey Lynn, Devonport, Herne Bay, Parnell, Kingsland) — timber sash villas and bungalows that look wrong with aluminium. Retrofit double glazing or full timber replacement is usually the only option that doesn’t kill the value of the house.
Coastal suburbs (Mission Bay, St Heliers, Takapuna, Devonport, Browns Bay, Mairangi Bay) — saltwater corrosion is real. Aluminium needs to be marine-grade or thermally broken; standard aluminium powder coating can blister within 5–8 years on direct sea-facing walls. Timber needs serious maintenance discipline.
Modern subdivisions (Hobsonville Point, Long Bay, Karaka, Stonefields, Flat Bush) — aluminium joinery throughout, usually 15–25 years old by now. Insert windows or full aluminium replacement is the standard upgrade path. uPVC works here too, particularly if winter cold or condensation is a complaint.
💡 Property tip: Get the energy rating in writing before you sign anything. Double-glazed isn’t a single performance level — the U-value (heat loss rate) varies wildly between manufacturers. Ask for the Window Energy Rating Scheme (WERS) data on the specific units being quoted. A cheap “double glazed” unit can perform worse than a well-spec’d retrofit double glazing job.
The Hidden Costs Installer Quotes Don’t Include
This is the section that costs Auckland homeowners the most when they get it wrong. Most installer quotes price the joinery and the install — the bit they actually do. Everything else falls in your lap. And “everything else” can run anywhere from 15% to 40% of the total project cost.
Interior Gib Repair and Reveal Lining
When the old window comes out and the new one goes in, there’s almost always a gap between the new frame and the existing wall opening. The gib lining around the reveal (the inside surface of the window opening) often needs cutting back, patching, or replacing entirely. Budget $200–$600 per window for gib repair and reveal work, more if the existing wall is old plaster rather than gib.
This is the most commonly skipped line item in installer quotes. They’ll install the window beautifully — then leave you with a 15mm strip of bare timber and exposed wall edge around every opening.
Architrave and Trim Replacement
The old architrave usually comes off when the window comes out, and it rarely goes back on intact. New architrave needs to be cut, fitted, mitred, nailed, filled and sanded. If you’re working in a character home, matching the original profile is a real job — sometimes it’s a custom milling job to replicate a heritage profile.
Architrave and trim work runs $150–$400 per window depending on profile complexity. Across a 12-window house that’s $1,800–$4,800 — not a rounding error.
Internal Painting
Once the gib’s patched and the architrave’s fitted, none of it is painted. The new architrave is bare. The patched gib is bare. The wall around it has a tide-mark where the old trim used to sit. Painting is the make-or-break step — the difference between a job that looks finished and a job that looks like a builder walked off site.
Internal painting around new windows costs $80–$200 per window for touch-ups, or $300–$800 per window if the whole room needs repainting (which it usually does, because the new walls don’t match the existing paint colour exactly). For a full house re-joinery, internal repainting of all affected rooms typically adds $4,000–$8,000.
Exterior Cladding Repair
The exterior side is the bigger problem. When the old window comes out, the cladding around it gets damaged. Weatherboards get cut. Brick edges chip. Plaster systems crack. The flashings (the metal strips that direct water away from the window) need replacing. The new joinery needs proper sealing and flashing work to keep water out — this is the highest-stakes part of the job because getting it wrong causes leaks.
Exterior cladding repair runs $400–$1,500 per window depending on cladding type. Weatherboards are at the easier end. Plaster systems (Rockcote, Resene, Insulclad) and brick veneer sit at the upper end. Direct-fix plaster systems are the most expensive because they often need re-rendering of the affected panel.
— Superior Property Services Team
Curtain Rails, Blinds and Window Hardware
Easy to forget until install day. Existing curtain rails almost never line up with the new joinery — different reveal depth, different fixing points, different sightlines. Blinds need re-mounting or replacement entirely. Budget $150–$500 per window for curtain and blind rework, more if you’re upgrading to plantation shutters or motorised blinds while the walls are open.
Skip Bins and Rubbish Disposal
A full house re-joinery generates a serious amount of waste — old joinery, broken glass, gib offcuts, packaging. A 4m³ skip bin in Auckland runs $350–$500 for a week, and most full window jobs need at least one. Installer quotes often include this; many don’t.
💡 Property tip: When comparing quotes, ask each installer to mark “Y” or “N” against the following — gib repair, architrave, internal paint, exterior cladding repair, flashings, curtain rework, skip bin disposal. The quote with the most Ys is almost always the better value, even if the headline number is higher.
When You Need Council Consent and Other Auckland-Specific Factors
Auckland Council has specific rules about when window replacement triggers a building consent — and getting this wrong can hold up a property sale or cost you in retrospective compliance. Most window replacement work doesn’t need consent. Some absolutely does.
When Window Replacement Needs Building Consent
Under the Building Act 2004 (Schedule 1), like-for-like window replacement is generally exempt from building consent — meaning replacing an existing window with a new window of the same size and configuration usually doesn’t need council sign-off. The exemption covers same-size joinery, same opening, same structural configuration.
You do need consent if: you’re changing the size of the opening, removing or modifying a structural lintel, adding a new window where one didn’t exist, changing the configuration significantly (e.g. casement to ranchslider), affecting weathertightness of a multi-unit dwelling, or working on a building scheduled as historic by the council.
The MBIE guidance on this is published on building.govt.nz — Schedule 1 exemptions under the Building Act are the relevant section. For Auckland-specific questions, Auckland Council’s building consent team is the authority. If you’re unsure, a 10-minute call to their consent helpline before quoting can save weeks of grief.
Character Home and Heritage Suburb Considerations
If your house sits in one of Auckland’s Special Character Areas (large parts of Mt Eden, Ponsonby, Grey Lynn, Kingsland, Westmere, Devonport, Parnell, Herne Bay), the rules tighten. Replacing timber sash windows with aluminium is usually not permitted under the Auckland Unitary Plan. You’re effectively required to either repair the existing joinery, retrofit double glazing into the original frames, or replace with timber in the original profile.
This is one of the strongest cases for retrofit double glazing in Auckland — it keeps you compliant with character home rules while delivering the thermal upgrade you actually want. Trying to slip aluminium joinery into a Mt Eden character zone home is a sure way to get a council enforcement notice mid-renovation.
Modern Subdivision Aluminium Joinery
If your house was built between 2000 and 2010, your aluminium joinery is approaching the end of its design life — particularly the seals around insulated glass units, which typically fail at 15–25 years. The pattern we see in suburbs like Stonefields, Botany, Albany and Long Bay is double-glazed seals failing one window at a time, with homeowners replacing IGUs reactively for 5–10 years before deciding to do the whole house at once.
If three or more of your IGUs have fogged, doing the whole house in one job is almost always cheaper per window than continuing to replace them individually. Bulk pricing on insert windows or full replacement breaks even at around 6–8 windows in our experience.
Pre-Sale Window Upgrade Strategy
Selling soon? Window replacement is one of the higher-ROI pre-sale upgrades, but only in specific circumstances. Fogged double-glazed units are a clear deduction on a building report: every fogged unit will be flagged. Replacing them before listing is usually worth it. Full joinery replacement six months before sale rarely returns the cost — the buyer values it less than you spent.
The honest pre-sale framework: fix anything that will be flagged on a builder’s report (fogged IGUs, broken sashes, damaged glass), skip the cosmetic upgrade (new joinery purely for looks). Run the cost-benefit through a real estate agent who knows your suburb — they’ll tell you whether your specific market values upgraded joinery.
💡 Property tip: Before you accept any quote in a Special Character Area suburb, ask the installer to confirm in writing that the proposed replacement complies with the Auckland Unitary Plan’s character home rules. If they don’t know what those rules are, get a different installer.
Repair, Retrofit or Replace — The Decision Framework
The most common mistake we see is homeowners jumping to full replacement when their actual problem could be fixed for a fraction of the price. The opposite mistake, repairing windows that are genuinely past saving, costs more in the long run because you end up doing the job twice. Here’s the framework we use when a homeowner asks us to look at their windows.
Repair Makes Sense When…
One window is broken or fogged. The frame is sound. The seals around the frame haven’t failed. You’re not planning a renovation that will involve those walls. The house is at least 5 years away from any other major work.
In this case, repair the one window. Get the glass replaced or the IGU swapped. Move on. Spending $500 on a one-off glass replacement is almost always better than spending $25,000 on a full house re-joinery because one IGU failed.
Retrofit Double Glazing Makes Sense When…
You have a character home with timber sashes you want to keep. The timber is in reasonable condition (some maintenance needed but not rotting). You want better thermal performance without the cosmetic and consent issues of aluminium replacement. You’re in a Special Character Area where replacement is restricted anyway.
This is the underused option in Auckland. A retrofit job on a 12-window villa runs $8,000–$15,000 — significantly cheaper than full replacement, doesn’t trigger consent issues, doesn’t damage cladding, and preserves the character look that makes the house worth what it’s worth.
Full Replacement Makes Sense When…
Three or more windows have failed seals or rotting frames. The aluminium joinery is 25+ years old and showing whole-house degradation. You’re doing a major renovation and the walls are open anyway. You’re changing window sizes or configurations. You need to address weathertightness issues that go beyond the glass.
The trigger to know: if you’re already calling tradies in for other work (kitchen, bathroom, recladding, extension), that’s when full window replacement starts making sense, because the marginal cost of doing the windows at the same time is dramatically lower than doing them as a standalone job.
The “You’re Already Opening the Wall” Trigger
Window replacement costs drop substantially when the rest of the house is already being worked on. If you’re recladding (which Auckland needs heaps of with the leaky homes legacy), if you’re doing a major addition or extension, or if you’re renovating a room and the gib is already coming off — that’s the moment to do the windows. Doing windows during an existing renovation can save 30–50% on the per-window cost compared to a standalone window job because the cladding, gib and painting work is already being done anyway.
For renovation-scale window work, the better contact is often Superior Renovations, our parent renovation business, because the window job is folded into the broader renovation scope rather than priced as standalone.
For everything else (single-window replacement, fogged IGU swaps, retrofit double glazing, between-tenancy turnover work, pre-sale upgrades) that’s our lane. We coordinate the joiner, the builder, the painter and the gib stopper so you get one quote, one project manager, one accountable point of contact, and a finished job that looks right.
Auckland Window Replacement — What Most Homeowners Pay
Putting it all together: the realistic total cost ranges Auckland homeowners pay in 2026, by job scope.
| Job Scope | All-In Cost Range | Typical Auckland Example |
|---|---|---|
| Single fogged IGU swap | $300–$700 | Failed seal in a bedroom window |
| Single window replacement (insert) | $2,000–$3,500 | One aluminium bedroom window swapped |
| Single ranchslider replacement | $4,500–$8,000 | 3m sliding door replaced like-for-like |
| Full villa retrofit double glazing (12 windows) | $8,000–$15,000 | Mt Eden bungalow keeping original sashes |
| Full house insert windows (12–15 units) | $22,000–$32,000 | 2000s subdivision aluminium upgrade |
| Full house joinery replacement (12–18 units) | $25,000–$45,000 | Whole-house re-joinery with painting and gib work |
| Full house with thermally-broken aluminium or uPVC | $32,000–$55,000 | Premium thermal performance upgrade |
These numbers reflect all-in costs: joinery, install, gib, paint, architrave, exterior repair, skip bins, the lot. Installer-only quotes will look 20–30% lower because they exclude the surrounding trade work. That’s not the installer being dishonest — it’s just outside their scope. It’s still inside your budget though.
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Window Replacement Cost NZ — Frequently Asked Questions
How much does it cost to replace one window in Auckland?
A single window replacement in Auckland typically runs $2,000–$3,500 for an insert-style aluminium window, $2,400–$3,500 for full joinery replacement, or $400–$700 for retrofit double glazing into an existing timber frame. Glass-only replacement (fogged IGU or broken pane) is much cheaper at $300–$1,200 per pane. The total cost depends on window size, material, and how much gib repair, architrave work and painting is needed around the new opening.
Is it cheaper to retrofit double glazing or replace windows entirely?
Retrofit double glazing is substantially cheaper — typically $400–$800 per square metre installed, compared to $2,400–$3,500 per unit for full joinery replacement. For a 12-window character home, retrofit comes in at $8,000–$15,000 versus $25,000–$45,000 for full replacement. The catch is that retrofit only works if the existing frame is in good condition. If the timber is rotting or the aluminium is warped, you need full replacement.
Do I need a building consent to replace windows in Auckland?
Like-for-like window replacement is generally exempt from building consent under Schedule 1 of the Building Act 2004 — meaning same size, same opening, same configuration usually doesn't need council sign-off. You do need consent if you're changing the opening size, modifying a structural lintel, adding a new window where one didn't exist, or working on a heritage-scheduled property. For Special Character Area homes (parts of Mt Eden, Ponsonby, Grey Lynn, Devonport), Unitary Plan rules also restrict what materials are permitted. When in doubt, call Auckland Council's consent helpline before committing to a quote.
How long does window replacement take?
A single window replacement typically takes half a day to one full day on site. A full house re-joinery for 12–15 windows usually runs 5–10 working days for the install itself, plus another 3–7 days for the gib repair, painting and architrave work afterwards. Retrofit double glazing is faster — most retrofits do 3–5 windows per day. Plan for 2–4 weeks total project time on a full-house job once you factor in lead times for the joinery itself, which can be 4–8 weeks from order to delivery.
What's the difference between insert windows and full replacement windows?
An insert window slides a complete new window unit inside the existing opening — the surrounding cladding, gib and architrave stay untouched. Cost is lower ($2,000–$2,500/unit) and disruption is minimal, but you lose 25–40mm of glass area on each side. Full replacement removes the entire window and rebuilds the opening, including new flashings, gib, architrave and exterior cladding repair. Cost is higher ($2,400–$3,500/unit) but you get a clean install with no compromise on glass area, and you can change the window configuration if you want.
Can I replace just the glass instead of the whole window?
Yes — and for many Auckland homeowners this is the right answer. If the frame is sound and only the glass is damaged or the IGU has fogged (failed seal), glass-only replacement runs $150–$800 per pane for single glazing, or $300–$1,200 per unit for a sealed double-glazed unit. The job typically takes 1–2 hours per window. The only time glass-only doesn't work is when the frame itself is rotten, warped, or has failed seals around the perimeter — in which case you're replacing the joinery, not the glass.
Why are window replacement quotes so different from each other?
Because they're often pricing different scopes. A $18,000 quote and a $26,000 quote on the same job frequently aren't quoting the same work — one might be supply-and-install joinery only, while the other includes gib repair, architrave, internal painting, exterior cladding repair, and rubbish disposal. The hidden costs typically add 15–40% to the headline installer quote. The honest comparison is to ask each installer for a line-by-line scope showing what's included and what isn't.
Will new double-glazed windows reduce my power bill?
Yes, but the payback period is longer than most installers suggest. EECA estimates that double glazing reduces heat loss through windows by 30–50% compared to single glazing, which in an Auckland climate typically saves $200–$500 per year on heating costs. Against a $20,000 full house upgrade, that's a 40–100 year payback purely on energy. The genuine return is in comfort (warmer rooms in winter, less condensation), property value (especially for sale) and noise reduction — not energy savings alone.
Are uPVC windows worth the extra cost in Auckland?
uPVC outperforms standard aluminium on thermal performance by 20–30% and dampens sound better — both real benefits if your house gets cold in winter or sits near a busy road. The extra cost is typically 10–20% over comparable aluminium ($900–$1,600/m² vs $800–$1,500/m²). The trade-off is chunkier frame profiles (less glass area), slightly longer lead times because more uPVC is imported, and lower visual appeal in modern architectural styles. For coastal Auckland homes where saltwater corrosion is a factor, uPVC also outlasts non-marine-grade aluminium significantly.
Can I claim insurance for a broken window?
Most home insurance policies in NZ cover accidental glass breakage and storm damage. The excess typically runs $300–$500, which means insurance is worthwhile for larger panels or full window units, but often not worth claiming for a small single-pane replacement under $500. Check your policy specifically for glass cover — some policies include unlimited glass replacement without affecting your no-claims bonus, which changes the calculation entirely. For storm or impact damage, document the cause and timing for the claim. For seal failures (fogged IGUs), most insurers will not cover this — they class it as wear and tear, not damage.
What's the cheapest way to replace single-pane windows with double glazing?
Retrofit double glazing — $400–$800 per square metre installed. The existing timber or aluminium frame stays in place, and only the single-pane glass is replaced with a sealed double-glazed insulated unit. Across a 12-window Auckland house, retrofit runs $8,000–$15,000 compared to $25,000–$45,000 for full joinery replacement. Retrofit only works if the existing frame is in good condition — rotten timber or warped aluminium needs full replacement. For most character home owners in Mt Eden, Ponsonby, Devonport or Grey Lynn, retrofit is the right answer both on cost and on heritage compliance.
How do I choose between aluminium and timber for a character home?
In Auckland's Special Character Areas — large parts of Mt Eden, Ponsonby, Grey Lynn, Kingsland, Westmere, Devonport, Parnell, Herne Bay — the Unitary Plan generally requires timber joinery or retrofit double glazing into existing timber frames. Aluminium replacement is usually not permitted in these zones, and council enforcement is active. Even outside character zones, timber holds up the visual integrity of a villa or bungalow in a way aluminium cannot match. The cost premium is real — $1,200–$2,200/m² for timber vs $800–$1,500/m² for aluminium — but the trade-off is the resale value of an authentically restored character home, which usually returns the cost on sale.
References
- Building Performance (MBIE) — Building Act 2004 Schedule 1 exemptions
- Auckland Council — building consents and the Auckland Unitary Plan
- EECA Energywise — Windows and double glazing