How much double glazing costs in Christchurch
Published NZ installer pricing, 2026, incl GST
$10,000–25,000
for a typical 3-bedroom retrofit, and about $400–1,200 per pane depending on the frame.
Retrofit is quoted per pane of glass, not per window. Most windows have two panes, one fixed and one that opens, so a ten-window house is usually about twenty panes. That's one of the main reasons two quotes for the same house can look so different. For how the work itself is done, see retrofit double glazing, or go back to Double glazed windows in Christchurch.
None of the figures on this page are this site's rates. They are what NZ installers published in 2026, checked in September 2026, and the Christchurch-specific numbers rest mainly on one local installer's guide. They will be replaced with the installer's own rate card once one is signed.
Price ranges
Published NZ installer pricing, 2026, incl GST
| Job | Price | Unit of pricing |
|---|---|---|
| Retrofit, aluminium framesper pane | ~$400–900 | per pane |
| Retrofit, timber framesper pane | ~$800–1,200 | per pane |
| Typical 3-bedroom retrofitwhole house | $10,000–25,000 | whole house |
Note: prices are per pane of glass, and most windows have two panes. Count the panes, not the windows, when you compare quotes.
What retrofit costs compared with replacement
Retrofit
Cheaper per opening, faster, and less to make good inside. You're limited by the frames you already have. A 3-bedroom house: $10,000–25,000.
Replacement
Dearer, but you get new frames, better seals, and the chance to change how the window opens. A 3-bedroom house: $25,000–45,000 in standard aluminium, $32,000–60,000 in thermally broken aluminium or uPVC.
Publishers who give both figures put retrofit at roughly 30 to 40% below replacement for the same house. The gap widens once making good is counted: new windows can mean gib, architraves, paint and sometimes cladding repair, and installer-only quotes that leave those out can run 20 to 30% under an all-in price. Ask which one you're looking at.
Cost by frame type
| Frame and method | Published range, incl GST | Confidence |
|---|---|---|
| Aluminium, retrofit | ~$400–900 per pane | Medium. Two independent publishers agree, but one prices per pane and one per window |
| Timber, retrofit | ~$800–1,200 per pane | Medium-low. Publishers quote identical figures, which suggests one copied the other |
| Standard aluminium, replacement | ~$1,200–2,500 per window | Low-medium. Whether making good is included explains most of the spread |
| Thermally broken aluminium, replacement | ~$2,000–3,500 per window | Medium-low. Roughly 25 to 40% over standard aluminium |
| Aluminium sliding door, replacement | ~$2,500–12,000 per door | Low. Size drives it, and door glass has to be safety glass. See replacement windows and doors |
| uPVC, replacement | Not published here | Sources disagree by 2 to 4 times on whether uPVC sits above or below thermally broken aluminium |
| Timber, replacement | Not published here | Only per-square-metre figures exist, from one copied table. Publishers agree it is the dearest frame |
| Secondary glazing | Not published here | Published figures conflict by 2 to 4 times. Every source says it costs well under a retrofit |
Why some boxes are empty: where the published figures conflict badly, we've left the box empty rather than pick a number. The installer's quote will fill it in.
What a three-bedroom house typically costs
Take a single-storey 1980s house with ten aluminium windows, most of them one fixed pane beside one awning sash. That's about 18 to 20 panes, and at the published range the glass alone comes to $8,000 to $18,000. The same house in timber is roughly double, and every laminated safety pane adds several hundred dollars.
Retrofit, aluminium frames
$10,000–18,000
The cheaper end, because the units are straightforward and the frames are usually in good shape.
Retrofit, timber or mixed frames
$15,000–30,000
More joinery work per pane: routing, new beads, and sash rebalancing on double-hungs.
Full replacement, worked example
~$29,500
Eight windows, two glazed doors and a slider in aluminium with low-E, installed and consented. $35,000–42,000 in uPVC or timber.
Published NZ installer pricing, 2026, incl GST. Christchurch homeowners posting their own quotes online report about $10,000 for an aluminium 3-bedroom and $22,000 for a timber one: anecdotal, but it sits inside the published range.
Double glazing cost calculator
Get a rough price range for your house from published NZ installer pricing, 2026, incl GST. It's only an estimate. The real price comes after a measure.
Retrofit runs about $400–900 per pane in aluminium and $800–1,200 in timber. Replacement is about $1,200–2,500 per window in standard aluminium and $2,000–3,500 thermally broken.
What moves the price
Glass area and unit count
The biggest driver by far. Large panes cost more each, and the number of separate panes matters more than the number of windows.
Frame material and condition
Timber retrofit needs more labour than aluminium. Rot or corrosion adds repair work, or rules retrofit out. One calculator adds 10 to 25% for repairs.
Glass spec
Low-E coatings, argon, warm-edge spacers and acoustic laminate each add a margin. Publishers put low-E and argon together at roughly 10 to 20% over clear glass.
Safety glass
Doors, side panels, low panes, bathrooms and stairways need safety glass under NZS 4223.3. A laminated pane can add several hundred dollars to a unit, and heavier units take longer to fit.
Access and storeys
Upper floors mean scaffolding or a platform, which one publisher puts at $1,000 to $5,000 on a job.
Job size and travel
More windows at once lowers the per-pane price, because the visit and set-up are spread further. Jobs outside the city may carry travel.
What a quote should include, and why quotes differ
A common complaint from Christchurch homeowners is two quotes for the "same" job that are thousands of dollars apart. It nearly always comes down to what each one includes. Before you compare totals, check each quote covers these seven things.
What a unit is
Is it priced per pane, per window or per frame? Count them yourself.
The glass
The low-E grade, whether there's argon, the spacer type and the pane thickness. "Double glazed" on its own doesn't tell you much.
Hinges and stays
Sealed units are heavier. Several Christchurch homeowners report hardware left as it was. Ask which windows get new hardware.
Safety glass
Which panes need it under NZS 4223.3, and whether it's priced in.
Making good
Who does the beads, paint, architraves, gib and cladding. This matters most with new windows.
GST
Some price directories quote without GST, which makes a 15% difference.
Deposit and timing
How much is due up front, and a realistic install date. Installers are busiest in winter.
Your protections, by law
Every job, any price
Implied warranties that the work is done competently with suitable materials, and 12 months from completion to report defects, which the contractor must fix.
$30,000 or more, incl GST
A disclosure statement and checklist before you sign, and a written contract saying who does what, when, and how defects are handled.
Got a quote you're not sure about?
Count every separate pane of glass the quote covers, enter the total, and see the price per pane against published retrofit pricing.
Quote total ÷ panes of glass = price per pane. $400–1,200 per pane is normal for retrofit.
Want a second opinion? Send the unit count and glass spec, and the installer can quote on exactly the same job.
Is it worth the money?
On comfort and condensation, usually yes, if the frames are sound. EECA says a poorly insulated home can lose up to 40% of its heating energy through the windows, and that double glazing brings that down to 25% or less. Consumer NZ's version is that about half the heat lost from a well-insulated single-glazed home goes through the glass, and double glazing roughly halves it.
On the power bill alone, be sceptical of anyone who gives you a payback year. We couldn't find a reliable saving figure for a Christchurch house, so we haven't made one up. What you're really paying for is a warmer, drier house that's cheaper to heat, and it's only money well spent if the windows are the weak point. Our comparison of retrofit vs new windows vs secondary glazing goes through when that's the case.
Ways to pay
- 0%Westpac, up to $50,000 over 5 years
- 1%BNZ and ASB, fixed 3 years, up to $80,000
All three need an existing home loan with that bank and about 20% equity. There's no government grant for glazing, so this is the realistic route. Rates checked September 2026.
You can also do the job in stages, starting with the living areas and bedrooms. The double glazing finance page has every product, the conditions and what to check in an installer's own finance offer.
Cost FAQ
How much does it cost to double glaze existing windows in NZ?
Published NZ installer pricing for 2026 puts retrofit at roughly $400 to $900 per pane in aluminium frames and $800 to $1,200 in timber, including GST. That is per pane of glass, not per window, so a window with one fixed pane and one that opens is priced as two. Low-E glass and argon are often included in those figures, but some publishers add 10 to 20% for them.
How much does it cost to double glaze a 3-bedroom house?
Retrofit: $10,000 to $25,000, with aluminium at the lower end (about $10,000 to $18,000) and timber or mixed frames at the upper end. Full replacement: about $25,000 to $45,000 in standard aluminium, or $32,000 to $60,000 in thermally broken aluminium or uPVC. All published installer pricing, 2026, including GST.
Is a quote "per unit" per pane or per window?
Ask, because publishers use both. Two of the best-known pricing pages price per pane of glass and say the average window has two panes. Others say "per window" without defining it. If one quote counts panes and another counts windows, the cheaper-looking one may not be cheaper at all.
Is it worth replacing 10-year-old double glazing?
Usually only if the units have failed. A sealed unit that has fogged between the panes has lost its seal, and a glazier can replace that unit on its own, which published Auckland pricing puts at a few hundred dollars each. Working units from 2016 are not far behind a new unit in performance. Spend the money on the single-glazed windows first.
How long does double glazing last?
No reliable published lifespan exists, so be wary of anyone quoting a precise number of years. What we do know is that the Building Code expects windows to last at least 15 years, and a sealed unit that fails shows it by fogging between the panes. That one unit can be replaced without touching the frame. Ask what warranty the installer gives on the units and on the work, and remember every job carries a 12-month defect period.
Is double glazing worth it in NZ?
For a single-glazed Christchurch house with sound frames, the case is strong on comfort and condensation. On power bills alone the payback is slow, and anyone who quotes you a precise saving is guessing. The guide to whether retrofit is worth it goes through it by situation.
Can I do the bedrooms first and the rest later?
Yes, and plenty of people do. The catch is that small jobs cost more per pane because the site visit and set-up are spread over fewer windows, so ask the installer to price the whole house and a first stage side by side. Living areas and bedrooms are the usual first stage.
Get a price for your house
The installer measures on site and prices each pane, with GST included.