Double glazed windows for older Wellington homes
Double glazed windows are worth pricing if the glass is cold to sit beside and you can feel air coming in around the old sashes, since Wellington's heating season runs longer than Auckland's. About one in seven Wellington City homes was consented after mid-2008, when new houses effectively had to have double glazing. The other six in seven or so predate it.
Ask for a quote
Most Wellington homes predate the mid-2008 change
The change took effect on 30 June 2008 for new homes in all eight councils of the Wellington region, and it raised the thermal requirements they had to meet. Across the region, more than half of today's homes were built before 1980. Roughly one in five went up before 1950.
An older house isn't always single glazed. Some have had new glass or new windows since, so start with what's in your frames now.
Consented after 30 June 2008
About one in seven
Wellington City homes
About one in six homes across Wellington City, the Hutt, Porirua and Kāpiti
More than nine in ten stand-alone houses in Wellington City predate the change
Our arithmetic, from Stats NZ building consent data and the 2023 Census.
Wind, draughts and the wind zone at your address
NIWA calls Wellington "undoubtedly the windiest city in the country". Kelburn records gusts over 61 km/h on 198 days a year, against 55 at Auckland Airport and 51 at Christchurch Airport. Gusts over 94 km/h come on 52 days there, and on 3 and 1 at the two airports.
Cook Strait channels the wind, so it blows almost always from the north-north-west or the south-south-east. Spring is generally the windiest season, and gales come most often in winter. Below the hilltops the average speed drops, but the gusts can be much the same. Exposed and sheltered sites differ a lot.
Most of Wellington City's mapped urban area is in the very high or extra high wind zones, and parts need specific engineering design. The council's map is a guide only, since each site's zone comes from its own assessment under NZS 3604. Windows have to be labelled for the wind zone they're installed in, so if it comes to replacing windows, check what the labels will say.
At Kelburn, NIWA's figures put heating need at well over one and a half times Auckland's and about four-fifths of Christchurch's. In Upper Hutt it's close to Christchurch's, and the Wallaceville station there records about 24 air frosts a year.
Gust days
- Kelburn, Wellington
- Auckland Airport
- Christchurch Airport
Wind zones
- Low
- Medium
- High
- Very high
- Extra high
- SED
Where draughts get in
Draughts get in through gaps around the sashes and the frame, not through the glass, so new glass alone won't stop them. Ask whether a quote includes new seals.
- Down the sides of the sashes
- At the meeting rail, where the two sashes meet
- Along the sill
Which route suits leaking, rotten or sound frames
The state of the frames tells you more than the age of the house does. Leaks, rot and heritage rules each change what's worth pricing.
Water gets in around old aluminium frames in storms
What usually follows
Have the frames checked before you price new glass. Replacing the windows may be the better route.
Rot or patched repairs in timber sashes
What usually follows
New sashes can be made for the old frames, or the windows can be replaced.
Aluminium frames that are sound and dry
What usually follows
New glass may suit them. Ask whether a double glazed unit will fit the frames.
Timber frames in good order
What usually follows
New glass can go into the sashes you have, or into new sashes made for those frames.
A listed heritage building, a heritage area or a Character Precinct
What usually follows
Ask the council whether the work needs resource consent before anything is ordered.
If a window wore out early, generally before 15 years, replacing it can need a building consent.
Can't tell which of these fits your frames? Choose "Not sure yet" on the form, and a local installer can go over them with you.
Ask for a quoteWhat a glass unit and a whole house come to
One Wellington glazing firm publishes its retrofit prices per glass unit, meaning one pane or one sealed unit. A window with a fixed pane and an opening sash counts as at least two.
For a whole three-bedroom house, national figures put a retrofit at $10,000–25,000 and new standard aluminium windows at $25,000–45,000. GST isn't stated in those national figures.
What goes into a double glazing pricePublished by a Wellington glazing firm, February 2026, incl GST
Aluminium frames, new glass $550–850per glass unit
Timber frames, new glass $800–1,200per glass unit
Service area
Where enquiries can be covered
We take enquiries from across the Wellington region.
Wellington City Council's heritage and Character Precinct rules apply only in Wellington City. Elsewhere in the region, a different district plan sets the rules.
What happens after you send an enquiryPaying for it
Low-rate loans, and no grant for windows
There's no government or council grant for double glazing in Wellington. With enough equity in the house, you can talk to BNZ, ASB or Westpac about paying for it with a home loan top-up at a low rate or no interest. Each bank sets its own conditions and can change them, so check with your bank first.
Borrowing to double glazeHeritage buildings and Character Precincts
Wellington City's District Plan has its own rules for listed heritage buildings, heritage areas and the city's Character Precincts, so check whether your house falls under any of them before window work starts. For heritage buildings and heritage areas there's a simpler route when clear single glazing is replaced with clear double glazing in the frames already there. Clear glass isn't defined in the plan, though, and since most retrofit units are low-E, it isn't confirmed that a low-E unit qualifies. New frames count as an alteration.
Heritage rules for timber sashes and casements
Before you ask for a quote
Does the Building Code require double glazing?
For new homes, in effect it does. The regulator's explanatory note on the higher thermal requirements of mid-2008 gave double glazing as the example of how to meet them.
Replacement windows in an existing house don't have to meet the full new-home standard, but they can't perform worse than the windows they replace.
Do I need consent to change my windows?
A house of one or two storeys usually doesn't need a building consent for window work, though there are exceptions when replacing windows. Resource consent is another matter, set by your council's district plan, and the council can confirm what applies at your address.
How should I compare double glazing installers?
Compare their written quotes rather than their brand names, and put the same questions to each installer.
Before you sign, ask if the person doing the work is a Licensed Building Practitioner or is supervised by one. The quotes are easier to weigh up once you know what goes into a double glazing price in Wellington.
What should I budget for double glazing in Wellington?
Plan around a quote for your own windows, and check it against double glazing prices in Wellington before you commit.
Are there government subsidies for double glazing?
No. Warmer Kiwi Homes, the government programme, pays towards insulation and heat pumps for eligible owners living in a pre-2008 home, but not windows, so look at borrowing to double glaze instead.
What happens after I send an enquiry?
We pass your details to a local installer so they can get in touch about the windows. Later on, we may ring to ask how it went. You can read how enquiries work, including who runs this site.
Get a written quote for the windows you have
Once we have your name and the best number to call you on, we'll put you in touch with a local installer. When they come to measure, ask them to check the frames as well as the glass.