Retrofit Double Glazing in Dunedin
Window and Glass Repair Dunedin retrofits double glazing into existing timber and aluminium joinery right across the city. Instead of pulling your windows out, we machine the rebate or fit a new bead, drop a sealed unit into the frame you already have, and reseal it. The window looks the same from the street and the room stops being cold.
- Keeps your existing frames, so villas keep their character
- Roughly half the cost of full joinery replacement
- Most Dunedin projects land between $10,000 and $24,000
- Exempt from building consent as like for like work
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No New Zealand city suits this better. Dunedin holds the largest concentration of Victorian and Edwardian buildings in the country, a legacy of the 1861 gold rush, and the residential stock that came with it is timber sash on a scale nowhere else can match. Owners here do not want aluminium in a villa opening, and they are right. Retrofitting costs roughly half of full replacement and the disruption is measured in days.
What it costs in Dunedin
Cost guides put most Dunedin retrofit projects between $10,000 and $24,000, with the wider band running from about $4,000 for a small job up to well over $50,000 on a large character home. Per square metre of glass, retrofit models at roughly $450 to $800 against $800 to $1,600 for full replacement.
Two things push Dunedin quotes around. Hill suburbs add access and handling. And the colder climate zone lifts the glass spec, because Low E is the sensible default here rather than an optional extra. Low E typically adds around a third to the glass price.
Timber frames get checked before anything is ordered
A retrofit only works if the frame is sound and deep enough to carry the unit. On timber we probe the sill and the bottom rail first. Soft timber there has to be repaired before glass goes near it, otherwise you have put a twenty five year unit into a frame with five years left in it.
We quote the timber work and the glazing together so nothing appears halfway through. On a whole house lot we usually take the sashes back to the bench, do the repairs, glaze, repaint and refit, which gives a far better finish than working in place.
Getting the glass right for a cold city
The standard build is 4mm glass, a 12mm gap and 4mm glass. In Dunedin we would almost always put Low E on that, because the coating reflects radiant heat back into the room and the payback in a fifty frost day climate is real. Argon fill improves it again.
Laminated on the outer pane cuts noise, which matters on the arterial routes and around the student quarter. And in doors, wet areas and low level positions the glass has to be toughened or laminated under NZS 4223 whatever was there before.
Consent, and what the rules say
Retrofitting glass into existing frames on an existing home is like for like work, exempt under Schedule 1 of the Building Act. No consent, no council fees.
That changes if the opening is enlarged, structure is altered, or the work forms part of a larger consented renovation. Consented residential work has to meet R0.50 here, which a retrofit into a plain aluminium frame will not reach, so the two paths are worth keeping separate in your head.
Retrofit Double Glazing at a glance
- Typical Dunedin project
- $10,000 to $24,000 for a whole house
- Wider range
- About $4,000 at the small end, past $50,000 on large character homes
- Per square metre
- Retrofit around $450 to $800, full replacement $800 to $1,600
- Standard unit
- 4mm glass, 12mm gap, 4mm glass, Low E strongly recommended here
- Low E
- Adds roughly a third to the glass price
- Lead time
- Four to five weeks from measure to completion
- Consent
- Exempt as like for like work under Schedule 1
Retrofit Double Glazing in Dunedin: common questions
Is retrofit double glazing worth it in Dunedin?
In a city with about 50 ground frost days a year, yes. It gets you most of the thermal benefit of new joinery for roughly half the cost and keeps your frames.
Will it work on my villa's sash windows?
Usually. The rebate is machined deeper or a new bead is fitted, and the sash balance is adjusted for the extra weight. We check the timber first.
How long does a whole house take?
Four to five weeks from measure to completion is normal in Otago, with the time on site measured in days rather than weeks.
Does retrofitting get me to the R0.50 code minimum?
Not in a plain aluminium frame, no. R0.50 applies to consented work and needs a thermally broken, uPVC or timber frame. Retrofitting an existing home is exempt work, so the requirement does not apply, but it is worth knowing the difference.
Recent Dunedin jobs
Got three quotes for retrofitting the front of the house. Only ones who measured every opening and explained why the south facing rooms needed different glass. Fourteen windows over three days and the difference in the mornings is obvious.
Landlord here. Had four flats assessed before the inspections. Two just needed sashes freed up and stays replaced rather than new joinery, which saved me a fortune. Straight answers and a written report I could hand over.
Slider had been jamming for years and we assumed it needed replacing. Turned out to be rollers and a bent track. Two hours, a fraction of the price we were braced for.
Fogged unit in the lounge, measured on the Tuesday and in by the following Monday. Fair price and they cleaned up after themselves.
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