Retrofit vs Full Replacement
Compare retrofit approaches (secondary glazing and glass-only replacement) with full window replacement — cost, thermal performance, disruption level, frame condition requirements, and which approach makes sense for different situations.
Winner
Magnetite
Best overall option once average cost, coverage, and support reputation are weighed together.
Average Gap
$960
Difference in average pricing across overlapping glazing services.
Market Range
$150 - $16,000
The full low-to-high range across both providers.
Sydney, 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 MagnetiteAdelaide, SA · Est. 2012
From
$150
Average
$3,150
Coverage
4 areas
Best for: Budget-conscious South Australian homeowners and DIY-capable owners wanting affordable double glazing with the option to self-install for maximum savings.
Review Double Glazing SuppliesSide-by-Side Price Comparison
Compare overlapping service types directly so the right price anchor is clear before you purchase.
| Service | Magnetite | Double Glazing Supplies | Difference |
|---|---|---|---|
| Secondary Glazing (per window) | $360 | $310 | +$50 |
| Acoustic Secondary Glazing (per window) | $580 | N/A | - |
| Whole House Secondary Glazing (3-bed) | $7,200 | N/A | - |
| Large Window Secondary Glazing | $620 | N/A | - |
| Standard Window Retrofit (per window) | N/A | $530 | - |
| Whole House 3-bed | N/A | $11,500 | - |
| Supply-Only IGU (per unit) | N/A | $260 | - |
Pros & Cons
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
Double Glazing Supplies
Pros
- ✓Most affordable double glazing option in South Australia — competitive pricing for both supply-and-install and supply-only orders makes double glazing accessible to more homeowners
- ✓Supply-only option available for competent DIY installers — provides significant savings (30–50%) on labour costs for homeowners with the skills and tools to self-install
- ✓Wide range of IGU sizes and specifications available including Low-E, argon fill, acoustic, and tinted options — flexible stock means shorter lead times for standard sizes
Cons
- ✗Installation service area is limited to metropolitan Adelaide and surrounding regions — not available for installed projects outside South Australia
- ✗Smaller team than national providers — fewer installation crews means longer wait times during busy periods (autumn and early winter)
Bottom Line
Verdict
Magnetite's secondary glazing ($250–$500/window) and glass-only retrofit options offer the lowest-cost entry point for improved window performance. Double Glazing Supplies' full replacement service ($350–$750/window for retrofit, $8,000–$16,000 for whole house) and supply-only IGU option ($150–$400/unit) provide the most affordable path to true double glazing. Retrofit approaches (secondary glazing or glass-only replacement) cost 30–60% less than full frame replacement and cause minimal disruption — typically 15–30 minutes per window with no structural work required. Full frame replacement delivers the best overall performance (new seals, thermal break frames, modern hardware) but costs more and takes 1–2 hours per window with some plaster and paint touch-up usually required. The right choice depends primarily on the condition of your existing frames.
Choose Magnetite secondary glazing if your windows are heritage-listed, you are renting, or you want the cheapest possible improvement. Choose Double Glazing Supplies' retrofit service if your frames are in good condition and you want true double glazing at the most affordable price. Choose Double Glazing Supplies' supply-only option if you are a competent DIYer and want to save 30–50% on labour. Choose full frame replacement only if your existing frames are deteriorated, draughty, or lack a thermal break — in that case, the additional cost is justified by the significantly better overall performance.
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 Magnetite secondary glazing if your windows are heritage-listed, you are renting, or you want the cheapest possible improvement. Choose Double Glazing Supplies' retrofit service if your frames are in good condition and you want true double glazing at the most affordable price. Choose Double Glazing Supplies' supply-only option if you are a competent DIYer and want to save 30–50% on labour. Choose full frame replacement only if your existing frames are deteriorated, draughty, or lack a thermal break — in that case, the additional cost is justified by the significantly better overall performance.