Quick Answer

Double glazing in Melbourne costs $600–$1,500 per window for retrofit secondary glazing, or $800–$2,500 per window for full double-glazed unit replacement. A full home retrofit (15–20 windows) costs $12,000–$35,000. uPVC frames offer the best thermal performance; aluminium frames are cheaper but less efficient. Victorian government energy efficiency rebates may offset $1,000–$2,000.

A renovation specialist installing a double-glazed window in a Melbourne home
A renovation specialist fitting a new uPVC double-glazed window unit into a Melbourne brick home — uPVC frames provide the best thermal break and are increasingly popular in Dandenong and Frankston homeowners upgrading older aluminium windows.

Complete Cost Breakdown

Retrofit Secondary Glazing (Most Affordable Option)

Secondary glazing adds a second panel inside your existing window frame — it doesn’t replace your existing window. This is the most cost-effective entry point for Melbourne homeowners and works well in rentals where full window replacement isn’t approved.

Window Size DIY Kit Cost Professionally Installed R-Value Improvement
Small (600×900mm) $120–$250 $400–$700 +0.3–0.5
Medium (900×1200mm) $200–$350 $550–$900 +0.3–0.5
Large (1200×1500mm) $300–$500 $700–$1,200 +0.3–0.5
Sliding door (2.4m) $600–$900 $1,200–$2,000 +0.3–0.5
Pro tip: DIY magnetic secondary glazing kits from companies like SecondaryGlazingAustralia.com.au are effective for renters and owners with heritage windows. They remove without damage and can be taken when you move.

Full Double-Glazed Window Replacement

Full replacement involves removing existing single-glazed windows and installing new double-glazed units. This is the most effective solution for energy efficiency and noise reduction.

Frame Type Per Window (Supply & Install) Thermal Performance Best For
uPVC (best insulator) $900–$2,500 U-value: 1.4–2.0 W/m²K Maximum efficiency
Thermally broken aluminium $800–$2,200 U-value: 2.0–3.0 W/m²K Modern homes, durability
Standard aluminium $700–$1,800 U-value: 3.5–5.0 W/m²K Budget option
Timber $1,200–$3,000 U-value: 1.8–2.5 W/m²K Heritage homes
Composite (timber/aluminium) $1,100–$2,800 U-value: 1.6–2.3 W/m²K Premium aesthetics

Full Home Retrofit Costs

Home Size Typical Window Count Secondary Glazing Full Replacement
2-bedroom unit 8–10 windows $6,000–$12,000 $9,000–$22,000
3-bedroom house 12–16 windows $9,000–$18,000 $13,000–$30,000
4-bedroom house 16–22 windows $12,000–$26,000 $18,000–$45,000
An insulation specialist fitting a DIY magnetic secondary glazing panel inside a Melbourne lounge room
Fitting a DIY magnetic secondary glazing panel — this no-drill solution adds a 40–60mm air gap that reduces heat loss by 40–60%, and costs under $300 per window installed yourself.

What Affects Double Glazing Costs?

1. Glass Type

Standard double glazing uses two 4mm glass panes with a 12–16mm argon-filled gap. Low-e (low emissivity) glass adds a metallic coating that reflects radiant heat — essential for Melbourne’s mix of cold winters and hot summers (+$100–$300 per window). Laminated glass adds security and noise reduction (+$150–$400 per window).

2. Frame Complexity

Standard sliding or single-hung windows are cheapest to replace. Awning, casement, and bifold windows cost more due to hardware complexity. Unusually sized or heritage-style windows requiring custom fabrication add 25–50% to the per-window price.

3. Access Difficulty

Upper-storey windows require scaffolding or elevated work platforms (+$500–$1,500 per day). Old windows bonded with putty or non-standard fixings take longer to remove. Commercial-grade acoustic glass for Melbourne CBD apartments adds significant cost.

4. Heritage Overlays

Properties with heritage overlays (common in Brunswick, Hawthorn, Richmond) may need council approval before replacing windows. Some councils require like-for-like timber replacements, restricting uPVC options. Always check your planning overlay on the Victorian Government’s Planning Maps before ordering.

Energy Savings — Is It Worth It?

Scenario Annual Energy Saving Time to Payback Noise Reduction
Secondary glazing on 10 windows $200–$400/year 8–15 years Moderate (5–10 dB)
uPVC full replacement (10 windows) $400–$800/year 10–20 years Good (10–15 dB)
Thermally broken aluminium $300–$600/year 12–22 years Good (10–15 dB)
Low-e glass upgrade +$100–$200/year vs standard Faster payback Same as above
Pro tip: If your primary goal is noise reduction (Melbourne tram lines, main roads), laminated glass outperforms standard double glazing — the acoustic laminate layer breaks the sound frequency transmission that insulating gaps can’t stop.

Signs Your Windows Need Upgrading

Problem Cause Action
Condensation inside panes Failed double-glazed seal Replace the glass unit — seal repair is not permanent
Draughts around frame Perished rubber seals or warped frame Re-seal or leplace frame
Cold rooms near windows Single glazing conducting heat out Add secondary glazing or replace
Noise from street or neighbours Single or poorly performing glazing Acoustic laminated glass or secondary glazing
Frost or ice on inside glass Very cold room plus single glazing Urgent — add glazing to prevent mould growth

When to Call a Licensed Professional

Full window replacement must comply with the National Construction Code and local planning permits. Structural openings and load-bearing lintels must not be modified without a building permit. Use a registered building practitioner for any structural window alterations.

Safety warning: Never remove a window frame in a two-storey or above home without properly installing temporary bracing. Window openings in brick cavity walls can lose structural support if removed incorrectly.

Top 10 Tips and Gotchas

  • Get quotes from at least 3 companies — double glazing prices vary enormously in Melbourne.
  • Ask specifically about the gas fill — argon-filled gaps (12–16mm) outperform plain air gaps.
  • Check the U-value, not just the marketing — a lower U-value means better insulation (target <2.0 for Melbourne climate).
  • Low-e glass is worth the premium in Melbourne — it reduces summer heat gain as well as winter heat loss.
  • Secondary glazing is 60–70% as effective as full replacement at 30–40% of the cost — a great budget option.
  • Check your planning overlay before ordering — heritage properties have restrictions that can void your order.
  • Time your installation: avoid Melbourne’s peak summer (Dec–Feb) when glaziers are busiest and lead times blow out.
  • Ask about ventilation — well-sealed double-glazed windows can increase humidity if you don’t add trickle vents.
  • Victorian Household Upgrades Program may offer rebates — check at energy.vic.gov.au for current schemes.
  • Window films are not the same as double glazing — they reduce UV and some heat but don’t improve thermal insulation comparably.
Safety warning: Broken double-glazed units in upper storeys must be taped and boarded immediately — structural integrity of the remaining pane is reduced by the seal failure.
A renovation specialist sealing a uPVC window frame with silicone caulk
Sealing around a newly installed uPVC frame with silicone — a critical step that prevents water ingress and air leakage, which would eliminate most of the thermal benefit of double glazing.

Local Melbourne Resources

Victorian Energy Compare — find rebates and upgrade support

Sustainability Victoria — home energy efficiency guides

HIA (Housing Industry Association) — find registered glaziers

Bunnings — secondary glazing film and DIY draught kits

Victorian Building Authority — check building permits for window replacements

Frequently Asked Questions

Does double glazing add value to my Melbourne property?

Yes — a well-documented study from the Australian Housing and Urban Research Institute found energy-efficient features including double glazing can add 5–10% to property values in Melbourne’s cooler southern and eastern suburbs. Properties with 6+ star NatHERS energy ratings attract premium buyers.

Is double glazing worth it if I’m planning to sell in a few years?

Secondary glazing (cheaper, removable) is probably not worth it before a sale. Full window replacement is worth considering if your current windows are draughty or visually dated — real estate agents report that modern windows are a noticeable selling point, especially in established suburbs like Frankston, Narre Warren, and Berwick.

Can I double-glaze my existing aluminium windows?

Existing aluminium window frames can sometimes be retrofitted with double-glazed glass units (replacing the single-pane), but only if the frame is deep enough (typically needs 55mm+ depth for standard double-glazed units). A glazier can measure your existing frames. If not deep enough, a full replacement is required.

How long does double glazing installation take?

A typical 3-bedroom home (12–15 windows) takes 2–4 days for full replacement by a professional team. Secondary glazing is faster — a DIY homeowner can complete 1–2 rooms per day. Rooms need to be cleared of furniture and curtains before work begins.

What’s the difference between double glazing and laminated glass?

Double glazing has two panes with an air or gas gap between them — it’s primarily an insulation product. Laminated glass is a single unit with a plastic interlayer — it’s primarily a safety and acoustic product. You can get laminated double glazing (laminate on one or both panes) for both benefits.

A safety expert demonstrating fall protection on scaffolding during upper-storey window replacement
A safety expert demonstrating fall protection on scaffolding during upper-storey window replacement — working at height without proper scaffolding and harnesses is one of the most common causes of serious injury in home renovation.

Final Thoughts

Double glazing is one of Melbourne’s smartest energy upgrades — our winters are cold enough to make the investment worthwhile, and the acoustic benefits are a genuine quality-of-life improvement for homes near main roads, tram lines, or flight paths. Secondary glazing offers 80% of the benefit at 35% of the cost and is worth considering for budget-conscious homeowners.

  • Start with a free energy assessment to identify which windows lose the most heat.
  • uPVC frames deliver best thermal performance; thermally broken aluminium is a good durability compromise.
  • Check Victoria’s energy upgrade rebates before signing — schemes change annually.
  • For of either properties, secondary glazing is owner-approved and removable.
  • Always verify heritage overlay before ordering — non-compliant installations must be removed at your cost.