How much does double glazing cost in NZ?

Double glazing in New Zealand costs $800–$2,500 per window for aluminium-framed units (supply and install, GST-inclusive) in 2026. uPVC frames are similar at $900–$2,200 per window. A full 3-bedroom home (12–15 windows) typically costs $15,000–$35,000 for complete double glazing replacement. The main variables are window size, frame material, glazing specification, and whether existing frames are reused.

What's the difference between uPVC and aluminium double glazing in NZ?

uPVC frames have better thermal performance than standard aluminium because the frame itself doesn't conduct heat. Thermally broken aluminium frames (aluminium with a plastic insulating strip) perform comparably to uPVC. Standard aluminium frames are common in NZ but less thermally efficient. uPVC is more common in the UK and Europe; most NZ joiners work with aluminium. uPVC and aluminium double glazing are similarly priced in NZ.

Can I retrofit double glazing to existing aluminium frames in NZ?

Yes — if your existing aluminium frames are in good condition, a glazier can replace the single-pane glass units with double-glazed units (IGUs). This is called retrofitting and costs $300–$700 per window for the glass replacement only, considerably cheaper than full frame replacement. The frames must be wide enough to accept a double glazing unit (typically 28mm+). Many older NZ aluminium windows are too narrow for retrofitting and require full frame replacement.

Do I need a building consent for double glazing in NZ?

Like-for-like window replacement (same size, same opening type) generally doesn't require building consent in NZ. However, if you're changing window sizes, adding new windows, or making significant changes to an exterior wall, consent may be required. Replacement windows in a heritage area may require resource consent. Check with your local council if unsure.

Double Glazing Cost NZ 2026 — Window Replacement Prices Per Window

Q: Is double glazing worth it in NZ?

Double glazing is worth it in NZ for several reasons: it reduces heat loss through windows by 50–70%, eliminates condensation which causes mould and timber rot, reduces outside noise by 30–40%, and significantly increases home comfort in winter. The financial payback period is 12–20 years from energy savings alone, but the health benefits and reduced maintenance costs (no mould, no rot) often justify it much sooner. In Wellington, Christchurch, and colder southern cities it's particularly valuable.

Updated June 2026 8 min read

Double glazing is the single biggest window upgrade you can make to an NZ home — reducing heat loss by 50–70%, eliminating winter condensation, and cutting outside noise. In 2026, expect to pay $800–$2,500 per window for aluminium double glazing (supply and install), with full home projects running $15,000–$35,000 for a 3-bed home.

Double Glazing Cost Per Window — NZ 2026

Window type	Cost per window (supply + install, incl. GST)	Notes
Aluminium double glazing (standard)	$800–$1,800	Most common in NZ
Thermally broken aluminium	$1,200–$2,500	Better thermal performance
uPVC double glazing	$900–$2,200	Very good thermal performance
Timber double glazing	$1,500–$4,000	Premium, heritage appropriate
IGU retrofit (glass only, existing frame)	$300–$700	Where frames suit retrofitting

Prices per window assume a standard 900×1200mm casement or awning window. Bay windows, large bifolds, and custom shapes are priced separately — typically $3,000–$15,000+ for a set.

Full Home Double Glazing — Total Project Cost

Home size	Approx. windows	Full replacement (aluminium)	IGU retrofit only
2-bedroom	8–10	$8,000–$18,000	$2,400–$7,000
3-bedroom	12–15	$12,000–$27,000	$3,600–$10,500
4-bedroom	16–22	$16,000–$44,000	$4,800–$15,400
Large / 5-bed+	22+	$22,000–$55,000+	Quote required

Retrofitting IGU glass into existing aluminium frames is the budget option, but only works if frames are in good condition and wide enough (28mm+ sightline typically required).

What Drives Double Glazing Costs in NZ

Frame material — timber frames cost 2–3× more than aluminium; thermally broken aluminium adds 30–50% over standard aluminium
Glazing specification — low-e coating adds $50–$150 per window but significantly improves thermal performance; argon gas fill adds a modest premium
Window size and type — large bi-fold or sliding doors are substantially more expensive than standard casement windows
Joinery lead time — custom joinery from NZ manufacturers takes 6–12 weeks; imported uPVC may be faster
Access and scaffolding — upper-storey windows require scaffolding, adding $500–$2,000 per project
Disposal of old windows — removing and disposing of old single-glazed units adds $30–$80 per window
Heritage/character area requirements — some councils mandate specific frame colours or profiles

Secondary Glazing — The Budget Alternative

Secondary glazing involves fitting an additional pane of glass or acrylic inside your existing window without replacing the outer frame. It's significantly cheaper than full double glazing:

Option	Cost per window	Performance
DIY acrylic secondary glazing	$50–$150	Good for draught reduction
Magnetite / Ecoease secondary glazing	$400–$900	70–80% of full double glazing performance
Full double glazing replacement	$800–$2,500	Best thermal + acoustic performance

Magnetite-style secondary glazing (a magnetic acrylic panel that snaps to a magnetic strip fitted to the window reveal) is popular in NZ as a budget retrofit. It performs well for thermal improvement and is easily removed in summer.

Is Double Glazing Worth It in NZ?

The financial payback from energy savings alone is 12–20 years — long by most investment standards. But the true case for double glazing in NZ is health and liveability:

Eliminates condensation — condensation on cold single-glazed glass is a leading cause of mould growth in NZ homes
Warmer rooms — rooms feel significantly warmer at the same air temperature when cold surfaces are eliminated
Noise reduction — 30–40% reduction in outside noise; more with laminated glass
Property value — double glazing is now expected in new builds and adds value in the market
Reduces heating bills — $200–$600/year savings for a typical 3-bed home depending on climate and heating type

For Wellington, Christchurch, and southern cities, the combination of cold winters and high rates of condensation makes double glazing one of the highest-return home improvements available.

FAQ — Double Glazing Costs NZ

How much does double glazing cost per window in NZ?

Standard aluminium double glazing costs $800–$1,800 per window installed. Thermally broken aluminium is $1,200–$2,500 per window. uPVC is $900–$2,200 per window. Prices include supply, delivery, installation, and disposal of old glazing.

Can I retrofit double glazing to my existing aluminium windows?

Sometimes — if the existing aluminium frames are in good condition and wide enough (28mm+ sightline), a glazier can replace the single-pane glass with double-glazed IGU units for $300–$700 per window. Many older NZ aluminium frames are too narrow and require full frame replacement.

Do I need consent for double glazing replacement in NZ?

Like-for-like replacement (same size, same type) generally doesn't need building consent. Changing window sizes or adding new openings usually does. Heritage areas may require resource consent for any changes to exterior joinery.

What's the difference between thermally broken and standard aluminium?

Standard aluminium conducts cold through the frame, causing condensation on the frame edges even with double-glazed glass. Thermally broken aluminium has a plastic insulating strip through the frame which breaks the thermal bridge — performance is close to uPVC. The premium is worth it in colder NZ climates (Zone 4+).

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