Question 1

How much does double-glazed window retrofit cost in Berwick and South East Melbourne in 2026?

Accepted Answer

Single window retrofit runs $800–$1,500 per window for standard sizes (up to 1.2m × 1.2m, argon-filled IGU, clear Low-E). Full-house retrofit on a typical 70s–80s Berwick or Endeavour Hills brick-veneer (15–20 openings) lands at $18,000–$35,000 depending on glass spec and frame condition. Sliding-door upgrade $3,000–$5,000 per door. Bifold doors $4,000–$8,000 each. Acoustic IGU upgrade (35+ Rw) adds $2,000–$3,000 premium per window — relevant near the Monash Freeway, Princes Highway and Moorabbin flight path. The VIC Energy Upgrades (VEU) rebate offsets $200–$800 per window depending on baseline U-value and house size.

Question 2

What is an IGU and why does argon fill matter?

Accepted Answer

An IGU — Insulated Glass Unit — is a sealed sandwich of two glass panes separated by a 12–16mm spacer with a desiccant edge seal. The cavity is filled with argon gas, which is about 30% denser than air and conducts heat ~30% less. Argon-filled IGUs typically achieve a U-value of 1.6–2.0 W/m²K vs single glazing at 5.8 W/m²K — that's roughly three times more thermally efficient. We only install argon-filled IGUs as standard. Air-filled units are cheaper but lose performance and are not worth specifying in the 2026 VIC climate.

Question 3

Low-E coating vs regular glass — what's the real difference?

Accepted Answer

A Low-E (low-emissivity) coating is a microscopically thin metallic-oxide layer on the inside face of one of the IGU panes. It reflects long-wave infrared heat back to its source — keeping winter heat inside the house and rejecting summer radiant heat. A clear Low-E IGU drops U-value from ~2.7 (clear glass IGU) to ~1.6 W/m²K and SHGC from 0.76 to 0.55. Coating orientation matters: soft-coat Low-E goes on surface #3 (inside face of the inner pane) for cold-climate VIC homes — coating direction is the single most common spec mistake amateur installers make.

Question 4

Should I retrofit the existing timber frames or replace them entirely?

Accepted Answer

Depends on frame condition. For most Berwick / Endeavour Hills brick-veneer homes built 1970s–1990s the original red gum or western red cedar window frames are still structurally sound — we measure, machine new beads, and drop in a 20mm argon-filled IGU into the existing rebate. Saves $400–$700 per window over full replacement, keeps the period character, and is much faster (1 day for 15 windows vs 5 days for full reframing). Replacement makes sense when: frames are rotted at the sill, the opening size is wrong, you want to switch to thermally-broken aluminium for a modern look, or you're going from awning to sliding. We measure and tell you honestly at site visit — neither option is universally right.

Question 5

Do I qualify for the VIC Energy Upgrades (VEU) rebate?

Accepted Answer

Yes — single-glazed windows in existing Victorian homes are eligible for the VEU window upgrade activity. Rebate ranges roughly $200–$800 per window based on the area, climate zone (Berwick / SEM is Zone 6), and the U-value / SHGC of the new IGU. The owner doesn't apply directly — we lodge the activity certificate creation through our Accredited Provider, the rebate is netted off the invoice. You need: proof of single glazing at install, photographs of removed glass and new IGU rating sticker, and your address eligibility check. We handle the paperwork; you see the discount on the quote.

Question 6

What's the U-value and SHGC I should ask for?

Accepted Answer

For South East Melbourne (Climate Zone 6 — cool temperate), target a U-value at or below 2.0 W/m²K and SHGC of 0.45–0.55. That's achievable with a clear Low-E argon IGU in a thermally-broken aluminium or timber frame. For 7-star NatHERS rated new builds or major renos, target U ≤ 1.6 with SHGC tuned per orientation — north 0.55+, west 0.35 (block summer sun), south 0.45–0.50. We do orientation-specific specs on multi-window jobs — not a blanket spec everywhere, which is what cheap quotes do.

Question 7

How long does a double-glazing retrofit take from order to install?

Accepted Answer

From site measure to install: typically 6–10 weeks for custom IGUs (the glass is laminated and assembled to your exact dimensions in Melbourne — there's no warehouse stock for non-standard sizes). Install itself is usually 1–3 days for a full-house retrofit (15–20 windows), longer if reframing. We measure three times before order — once at quote, once at deposit, once before manufacturing release — because a 5mm error on a custom IGU is a $400–$700 board-up plus a re-order.

Question 8

Will acoustic IGUs really help with Monash Freeway or flight-path noise?

Accepted Answer

Yes — for homes within ~500m of the Monash, Princes Highway, EastLink, or under the Moorabbin Airport flight path (Hampton Park, parts of Dandenong, Endeavour Hills). Standard double glazing achieves Rw 31–33 dB. Acoustic IGUs — asymmetric glass thicknesses (e.g. 6mm + 10.38mm laminated) with optimised air gap — push that to Rw 38–42 dB. That's a perceptually ~half-as-loud reduction. The catch: acoustic performance only delivers if every air leak is sealed. A $3,000 acoustic upgrade with a sloppy frame seal performs no better than the standard IGU. Installer skill matters more than glass spec here.

South East Melbourne's specialist double-glazed window & door retrofitters.

Five double-glazing solutions.

Double-glazed windows

Double-glazed doors

Retrofit existing frames

Energy-efficient Low-E glass

Soundproof acoustic glazing

Three things every SEM double-glazing project needs to get right.

NatHERS 7-star ready, orientation-tuned.

VIC Energy Upgrades (VEU) rebate handled.

AS 2047 / AS 4666 compliance + AGGA membership.

Where we work.

From in-home measure to commissioned IGU — 5 stages.

In-home measure

Design & fixed quote

Manufacture

Install

VEU lodgement & warranty

Ready for a free in-home measure?