A warmer, drier house: double glazed windows in Christchurch
Double glazing a Christchurch house usually means one of two jobs: new sealed units in the frames you already have, or new windows altogether. Either way, this site sends your enquiry to a vetted local installer who measures and quotes.
Get a quoteNo more wiping down the bedroom windows on frosty mornings. The house gets a bit quieter too.
Illustrative image.
Retrofit or replace, which fits your house
Retrofit keeps the frames you already have and changes the glass. Replacement takes the whole window out, and it's the usual route when doors and sliders are part of the job. Which one suits you comes down to the state of your frames, and an installer can usually tell you which camp you're in from a look at two or three windows.
Keep your frames, change the glass
Sound aluminium frames and timber sashes can often take a sealed unit. The frames stay put, so there's less to make good afterwards than with new windows, and it's the cheaper of the two.
Retrofit double glazing →
Start again with new windows
For frames that are rotten, draughty or too slim for a unit. You get new frames and seals, and you can change how the window opens, with new aluminium or uPVC windows.
Replacement windows →Three questions that decide it
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Is the frame sound?
Press a screwdriver into the bottom corners of a timber sash, or look for corrosion and twist in aluminium. If it's soft, rotten or bent out of shape, that window needs replacing.
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Is there room for a unit?
A sealed unit is two panes and a gap thick. Most timber and most aluminium profiles have the depth, or can be adapted. Some slim older aluminium sections don't.
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Do you want the window changed?
A bigger opening, a slider onto the deck, a window that finally seals. Retrofit keeps the same window and makes it warmer. Replacement gives you a different one.
Many houses are a mix: retrofit throughout, with one or two replacements where the weather has got in. A good quote will say which is which, window by window.
Double glazing by frame type
The frames you have decide what can be done and what it costs. Aluminium is the quicker, cheaper retrofit. Timber costs more per pane but ends up warmer. If the frame has to go, the new window pages compare the materials.
Illustrative images, not the installer's work.
Aluminium windows
Many aluminium frames can be retrofitted. Some older profiles are too shallow to hold a sealed unit, and those become replacement jobs.
Timber and character windows
For villas, bungalows and other older homes. Sound timber can usually take a slim unit, with new beads made to hold it.
New windows: replacement, uPVC and aluminium
When the frame itself has to go, compare the materials on cost, warmth and upkeep.
What it costs in Christchurch
Published NZ installer pricing, 2026, incl GST. Retrofit is priced per pane of glass, not per window, and most windows have two panes, usually one fixed and one that opens.
Read the cost guide →- Retrofit, aluminium framesRetrofit, aluminium ~$400–900 / pane~$400–900
- Retrofit, timber framesRetrofit, timber ~$800–1,200 / pane~$800–1,200
- Typical 3-bedroom retrofit3-bed retrofit $10,000–25,000$10,000–25,000
Paying for it: 0% and 1% bank loans
There's no government grant for double glazing, but three banks lend for it at rates you won't see anywhere else. BNZ and ASB offer 1% fixed for three years on top-ups of up to $80,000 that list double glazing. Westpac offers 0% on up to $50,000, repaid over five years. ANZ's Good Energy top-up covers it too, though ANZ didn't show a rate when checked.
The catch is the same at each: an existing home loan with that bank and about 20% equity. If that's you, a $15,000 retrofit at 1% costs a lot less than putting it on the credit card. Rates checked September 2026. The finance options page has the conditions, what's available locally and some cheaper ways to start.
Wondering what your own windows would cost?
Send the frame type and roughly how many windows, and ask the installer for a rough range when they call.
Christchurch homes and double glazing
Most of the housing here was built before double glazing was normal, and the winters are cold enough to feel it. In modelled Christchurch houses, space heating is about 27% of the energy a home uses, against 4% in Auckland.
2007
Double glazing became effectively required for new South Island homes from 31 October.
~1 in 4
Christchurch homes have been consented since then.
85
Ground-frost days in an average year.
0.7°C
July mean daily minimum.
That leaves roughly three quarters of the city's homes built under older rules. Some of those have been retrofitted since, as Stats NZ points out, but a lot of 1960s to 1990s aluminium joinery and a good number of villa and bungalow sashes are still single glazed. Heat pumps are in about four out of five Canterbury homes now, so for a lot of people the windows are now the coldest thing left in the house.
Service areas
Christchurch city is the installer's home ground, from the Port Hills suburbs to the northern and western edges. Selwyn and Waimakariri depend on the installer: they'll tell you on the first call whether they can come out that far for your job and whether it costs extra. Put your suburb in the form and the installer will tell you when they call.
- Christchurch cityCovered
- Selwyn, including RollestonAsk on the call
- Waimakariri, including RangioraAsk on the call
- Further afieldDepends on the job
Double glazing FAQ
Do I need building consent for retrofit double glazing?
Usually not. Replacing windows or glass in the same position on a house of up to two storeys is exempt under Schedule 1 of the Building Act, although the work still has to meet the Building Code. One exception is a window that has rotted or failed within about 15 years of going in.
If your home is in a character area or heritage area, changing street-facing windows may need resource consent. Check your property on the Christchurch District Plan maps or ask the council's duty planner before you commit.
How much does it cost to double glaze a house in Christchurch?
Published NZ installer pricing for 2026 puts a typical three-bedroom retrofit at $10,000 to $25,000 including GST, with aluminium frames at the lower end and timber at the upper end. Per pane, that's roughly $400 to $900 in aluminium and $800 to $1,200 in timber. Replacing the windows altogether costs more again.
The double glazing cost guide breaks it down by frame type and explains why two quotes for the same house can be so far apart.
Can old aluminium windows be retrofitted?
Often, yes. It depends on whether the frame is straight and sound, and whether the rebate is deep enough to hold a sealed unit. Some older, slimmer profiles have nowhere to put one, and those become replacement jobs.
The frame limits the result, though. The Building Code's reference table rates standard double glazing at R0.24 in aluminium and R0.41 in timber. There is more on this on the aluminium double glazing page.
Does the government offer any subsidies for double glazing in NZ?
No. As at September 2026, no central or local government grant covers windows or glazing. EECA's Warmer Kiwi Homes pays for ceiling and underfloor insulation, and heat pumps for some owners, but not windows.
What does exist is bank finance: BNZ, ASB and Westpac all list double glazing as an eligible use of a low-rate home loan top-up. The double glazing finance page has the details and the conditions.
How do I choose between double glazing companies in Christchurch?
Compare the quotes rather than the brochures. Whichever double glazing installers you talk to, a good quote is itemised per pane, names the glass spec (low-E grade, argon, spacer type), says whether hinges and stays are being upgraded for the heavier glass, and identifies any panes that need safety glass. It should say what making good is included and whether the price includes GST.
Two protections apply to every residential job in New Zealand: implied warranties that the work will be done competently, and 12 months from completion to report defects. At $30,000 or more the installer must also give you a written contract and a disclosure statement before you sign.
Does double glazing stop condensation?
It usually cuts it back a lot, because the inner pane stays warmer. It won't fix a damp house on its own. Frames can still run wet, standard aluminium especially, and airing the house matters as much as the glass. See how to stop condensation on your windows.
Start with a measure and quote
Leave your name and number, and the installer will call to talk through the rest.