Double vs Secondary Glazing
Compare full retrofit double glazing with secondary glazing — thermal performance, noise reduction, cost, installation disruption, heritage suitability, and which approach delivers the best outcome for different property types and budgets.
Winner
Magnetite
Best overall option once average cost, coverage, and support reputation are weighed together.
Average Gap
$2,343
Difference in average pricing across overlapping glazing services.
Market Range
$250 - $20,000
The full low-to-high range across both providers.
Melbourne, VIC · Est. 2005
From
$400
Average
$4,533
Coverage
8 areas
Best for: Homeowners wanting a premium full-service double glazing experience from a national provider with strong warranty support, comprehensive surveys, and quality European glass.
Review Everest WindowsSydney, NSW · Est. 1998
From
$250
Average
$2,190
Coverage
9 areas
Best for: Heritage-listed properties, rental properties, and budget-conscious homeowners wanting improved thermal and acoustic performance without modifying or replacing existing windows.
Review MagnetiteSide-by-Side Price Comparison
Compare overlapping service types directly so the right price anchor is clear before you purchase.
| Service | Everest Windows | Magnetite | Difference |
|---|---|---|---|
| Standard Window Retrofit (per window) | $580 | N/A | - |
| Whole House 3-bed | $14,500 | N/A | - |
| uPVC Frame Replacement (per window) | $1,250 | N/A | - |
| Sliding Door Double Glazing | $1,800 | N/A | - |
| Secondary Glazing (per window) | N/A | $360 | - |
| Acoustic Secondary Glazing (per window) | N/A | $580 | - |
| Whole House Secondary Glazing (3-bed) | N/A | $7,200 | - |
| Large Window Secondary Glazing | N/A | $620 | - |
Pros & Cons
Everest Windows
Pros
- ✓Full national coverage across all capital cities with a network of accredited installers — consistent quality standards and warranty support wherever you are in Australia
- ✓Comprehensive survey and quotation process includes thermal imaging assessment to identify the most impactful windows to upgrade first — helps prioritise budget allocation
- ✓European-sourced insulated glass units with 15-year manufacturer warranty on seal integrity — superior quality compared to many locally manufactured units
Cons
- ✗Premium pricing reflects the brand's quality positioning — Everest Windows is not the cheapest double glazing option available
- ✗Lead times can be 4–6 weeks for custom IGU manufacturing — not suitable for urgent projects requiring immediate installation
Magnetite
WinnerPros
- ✓Australia's leading secondary glazing specialist with over 25 years of experience — the magnetic system is proven, well-engineered, and backed by extensive installation expertise
- ✓Ideal for heritage-listed buildings where original windows must be retained — Magnetite panels are virtually invisible from outside and do not alter the external appearance of the building
- ✓Most affordable entry point for improved thermal and acoustic performance — secondary glazing costs 30–50% less than full retrofit double glazing while delivering meaningful improvements
Cons
- ✗Secondary glazing is less effective thermally than true double glazing — the air gap and seal quality are not as good as a factory-sealed IGU
- ✗The secondary panel adds a visible layer to the interior of the window — some homeowners find this aesthetically less appealing than retrofit double glazing
Bottom Line
Verdict
Full retrofit double glazing from Everest Windows ($400–$800/window for standard retrofit, $10,000–$20,000 for a whole house) delivers superior thermal performance with a factory-sealed IGU, eliminates condensation between panes, and is invisible once installed. Secondary glazing from Magnetite ($250–$500/window, $5,000–$10,000 for a whole house) is 30–50% cheaper, retains original windows completely, and is the only viable option for heritage-listed buildings. Thermally, full double glazing achieves U-values of 1.2–1.6 W/m²K versus 2.5–3.0 W/m²K for secondary glazing. Both options significantly reduce noise — double glazing by 25–35dB and secondary glazing by 20–30dB. For most standard homes, full retrofit double glazing delivers better long-term value. For heritage properties or tight budgets, secondary glazing is the practical choice.
Choose full retrofit double glazing from Everest Windows if your frames are in good condition and you want the best thermal performance, condensation elimination, and long-term value. Choose secondary glazing from Magnetite if your property is heritage-listed, you are renting, or budget is the primary constraint. For heritage properties, Magnetite's magnetic secondary glazing system is the clear winner — it preserves original windows completely while delivering meaningful thermal and acoustic improvements.
Comparison FAQ
Magnetite is cheaper on average in this comparison, but the right answer depends on your specific requirements including window type, glass specification, frame condition, and whether the existing frames can accept retrofit IGUs or require full replacement.
The glass specification (thickness, Low-E coating, gas fill, spacer bar type), frame quality and thermal break performance, warranty terms (IGU seal warranty and installation warranty), installer accreditations, and the scope of work included (removal, disposal, sealing, scaffolding) usually affect the total cost and value more than a blended average. Always confirm exactly what is included in the quote.
Choose full retrofit double glazing from Everest Windows if your frames are in good condition and you want the best thermal performance, condensation elimination, and long-term value. Choose secondary glazing from Magnetite if your property is heritage-listed, you are renting, or budget is the primary constraint. For heritage properties, Magnetite's magnetic secondary glazing system is the clear winner — it preserves original windows completely while delivering meaningful thermal and acoustic improvements.