Window Replacement in Wellington

Most of the replacement work in Wellington falls into two groups. There is 1960s to 1980s single glazed aluminium, which is cold, whistles in the wind and streams with condensation every winter morning. Then there is timber joinery from the villa and bungalow era where the sills have gone soft at the bottom of the frame after eighty odd years of driving southerly rain. The two need completely different answers, and quoting them the same way is how people end up spending far more than they had to.

Three ways to replace a window, and what each one costs

Glass only replacement keeps your frame and swaps the pane. It runs about $250 to $600 for a standard sized single pane and $600 to $1,200 for a large one. It is the right call whenever the frame is sound.

Insert replacement drops a new unit into the existing frame or reveal, keeping the cladding and the flashings untouched. Full joinery replacement takes the whole thing out, which usually lands between $1,500 and $2,500 an opening for standard aluminium and more for thermally broken. Full replacement makes sense when the frame is corroded, the timber is rotten, or you want to change the configuration.

When 1970s aluminium has reached the end

The single glazed aluminium fitted through the 1960s, 70s and 80s was never insulated. The frame is a straight metal bridge from outside to inside, so it sits at outdoor temperature and pulls moisture out of the room air. That is where the puddle on your sill comes from.

Look at the corners. If the joints have opened, the powder coat is chalking, the rubbers have gone hard and flat, and the stays are pitted, the joinery is done. Replacing it gets you a warmer room and a quieter one, since laminated or acoustic glass cuts road and aircraft noise at the same time.

Timber joinery: repair the bottom, keep the top

Villa and bungalow joinery almost never rots evenly. The head and the stiles are usually fine because water runs off them. The sill and the bottom rail take the punishment.

So the honest answer on a character home is often not replacement at all. We scarf in new timber at the bottom, reglaze, repaint and leave the rest of a hundred year old window in place. It costs less than new joinery, it keeps the proportions and the glass, and it keeps you clear of any character or heritage rules that apply in Thorndon and Mount Victoria.

What replacement does to a Wellington power bill

Independent cost guides put the annual heating saving from double glazing in the Wellington and Christchurch climate zone in the range of $400 to $800 a year, against $200 to $500 in Auckland. That is a real number, though it depends heavily on how you heat and how long you run it.

The change most people notice is not the bill. It is that the bedroom windows stop dripping in June, the curtains stop going mouldy, and the room holds its heat for hours after the heat pump goes off.

Window Replacement at a glance

Glass only

About $250 to $600 a standard pane, $600 to $1,200 for large panes

Insert units

New unit into the existing frame, cladding untouched

Full joinery

About $1,500 to $2,500 an opening for standard aluminium

Whole house

Commonly $10,000 to $25,000 for a retrofit across 12 to 15 windows

Timber option

Scarf repair to the sill and bottom rail, keeping the original sash

Glass upgrades

Low E, argon, laminated acoustic, toughened safety glass

Consent

Not required for like for like replacement