The internet has a lot of double glazing content. Most of it is
generic. This article answers the 30 questions Perth homeowners actually
ask, with the specific 2026 numbers and the honest framing. Drawn from
AGWA, AS standards, NCC 2022, Bureau of Meteorology
Perth data, and confirmed double glazing
Perth market pricing.
The questions cluster into six topic areas: cost, energy, noise,
product, process and comparison. Use the table of contents in your
browser or just scroll. Every answer cites a source or notes where the
evidence is weak.
Cost Questions
What Does Double
Glazing Cost in Perth in 2026?
A single double glazed aluminium window in Perth runs $450 to $2,200
supply only depending on size and spec. A standard 1500 x 1500 mm
sliding window in thermally broken aluminium with low-e glass runs
$1,100 to $1,700 supply only. A whole-house project of 10 to 15 windows
plus 1 to 2 doors runs $24,000 to $57,000 supply and install for
thermally broken aluminium. Source: Penot
Double Glazing cost guide for Perth.
What
Affects the Price of Double Glazing More than Anything Else?
Window size first, then glass spec, then frame spec, then hardware
and finish. A 2400 x 1800 mm fixed picture window is roughly four times
the cost of a 1200 x 1200 mm awning of the same spec. Within size, the
biggest spec upgrade is the move from clear standard double glazed to
solar-control low-e, which adds $200 to $500 per window.
Is the
Cheapest Double Glazing Quote Ever Worth Taking?
Rarely. Two quotes that look 30 to 60 per cent apart usually have
different glass and frame specs. The cheapest quote often uses standard
non-thermally-broken aluminium frames with clear double glazed units,
which underperforms thermally broken aluminium with low-e on a Perth
west-facing room. Match specs before comparing prices. Our choosing a double
glazing company Perth guide covers what separates good suppliers
from average ones.
How
Much Does a Double Glazed Sliding Door Cost in Perth?
A standard 3.6 metre double glazed aluminium sliding door in Perth
typically sits at $1,200 to $3,500 supply only for standard spec, or
$2,000 to $4,500 for thermally broken frame with low-e glass. Larger 4.8
metre 3 or 4-panel doors run $2,000 to $6,500 supply only. Detailed
breakdown in our double glazed sliding
doors Perth cost guide.
How
Much More Does Triple Glazing Cost than Double Glazing?
Typically 30 to 50 per cent more per window. The premium reflects the
third pane, the wider frame profile required to carry the heavier IGU,
and the heavier hardware. For most Perth homes, the premium is hard to
recoup through energy savings alone. Full analysis in our triple glazed windows Perth
cost guide.
Energy Questions
How
Much Does Double Glazing Reduce Energy Bills in a Perth Home?
Indicative annual energy bill saving for a typical Perth home sits in
the range of $400 to $750, drawn from national glazing performance
modelling published December 2024 using AGWA 7-star data. Perth is not
directly modelled in the source data, so the figure is extrapolated from
Brisbane (the closest climate analogue). Perth tariffs have risen faster
than the eastern states over the past 5 years, so the Perth-specific
number could sit at the upper end of the range.
What Is the
Best Glass for Summer Heat in Perth?
Solar-control soft-coat low-e double glazed unit with an SHGC of 0.20
to 0.40. This drops the radiant solar load on west and unshaded north
windows by 50 to 70 per cent compared to standard clear double glazed
(SHGC ~0.70). Full thermal analysis in our does double
glazing keep Perth homes cooler in summer guide.
What Does SHGC Mean?
Solar Heat Gain Coefficient. A number from 0 to 1 that measures how
much of the sun’s radiant energy passes through the glass. Lower SHGC =
less heat enters. For Perth’s cooling-dominant climate (BCA Climate Zone
5), SHGC matters more than U-value for west-facing and unshaded
north-facing windows. Our U-values, SHGC and
window energy ratings in WA guide explains in detail.
What Does U-value Mean?
A measure of how quickly heat conducts through the window assembly,
in watts per square metre per degree Kelvin (W/m²K). Lower U-value =
better insulation. Standard single glazed aluminium runs around 5.5 to
6.6 Uw. Thermally broken aluminium with low-e double glazed sits at 1.8
to 2.5 Uw. Triple glazed best spec reaches 1.0 to 1.4 Uw.
What’s a Thermal
Break in an Aluminium Frame?
A polyamide (nylon) strip or foam insert that interrupts the
conduction path through an aluminium frame between the inside and
outside faces. Standard aluminium frames have a U-value around 6.6
W/m²K. Thermally broken aluminium drops to around 2.2 W/m²K. The thermal
break also prevents winter condensation on the internal frame face.
Noise Questions
How Much Noise Does
Double Glazing Block?
Standard 4 mm single glazed: ~29 Rw. Standard double glazed: ~32 Rw.
Acoustic laminated double glazed: 37 to 42 Rw depending on
configuration. The human ear perceives a 10 dB reduction as
approximately halving perceived loudness. Going from a 65 dB exterior to
a 40 dB interior is a transformative difference for sleep quality.
What Is the Best
Glass for Road Noise in Perth?
Acoustic laminated double glazed unit. The acoustic PVB interlayer in
the outer laminated pane absorbs sound energy across a wider frequency
range than standard PVB. Typical Rw values: 37 to 42, with some
configurations reaching 45 with thicker outer panes. For properties
within 200 to 300 metres of Kwinana Freeway, Mitchell Freeway or major
arterial roads, this is the right spec.
Do
You Need Acoustic Glass If You Live Under a Perth Flight Path?
Yes for sustained sleep-quality benefit. Acoustic laminated double
glazed delivers 15 to 25 dB of interior noise reduction compared to
single glazed for typical flight noise frequencies. The Penot Double
Glazing flight
path noise reduction page covers the specifications. Existing
research has documented the affected suburbs in detail; see our double glazing
near Perth Airport and busy roads guide.
Will
Double Glazing Help with Aircraft Noise Frequencies?
Yes, particularly with the acoustic laminated variant. Aircraft noise
has significant low-frequency content (engine rumble, descent thrust),
which is harder to attenuate than mid-range traffic noise. Acoustic
laminated glass and thicker outer panes are designed for this frequency
profile. The Rw + Ctr rating (an extension of Rw that weights
low-frequency noise) is the metric to ask about for flight-path-exposed
homes.
Product Questions
What
Is the Difference Between Double and Triple Glazing?
Double glazing has two panes of glass separated by an aluminium or
warm-edge spacer with an air or argon-filled gap (typically 12 to 16
mm). Triple glazing has three panes and two gas-filled gaps. Triple
delivers Uw 1.0 to 1.4 (best spec) vs 1.8 to 2.5 for premium double. For
Perth, SHGC matters more than U-value for most windows, so solar-control
double is often the better cost-performance choice over triple.
What Frame
Material Is Best for Perth Double Glazing?
Thermally broken aluminium dominates the Perth market for premium
double glazing. The thermal break addresses the conduction problem of
standard aluminium and delivers competitive thermal performance with the
durability and finish range that aluminium frames offer. Timber and
wood-alu hybrid frames suit heritage and architectural projects but
require more maintenance than aluminium.
What Is Secondary Glazing?
A separate pane of glass added to the inside of an existing window,
creating a sealed cavity between the original glass and the new pane.
Lower cost than full window replacement, suitable for some heritage
properties, and acoustic benefit is meaningful (though thermal benefit
is more modest than full IGU replacement). Secondary glazing can be a
stepped approach for budget-constrained projects or for heritage
properties where the original window must stay.
Do
You Have to Replace the Whole Window or Just the Glass?
For most aluminium frames built in the 1980s or later, the frames are
not designed for a 24 mm IGU and the rebate depth will not accommodate
the new glass. The standard approach is to replace the entire window
unit (frame plus glass) rather than swap the glass in an existing frame.
A small number of architectural aluminium frames can accept new IGUs; a
site measure is the only way to confirm.
Process Questions
How
Long Does Double Glazing Installation Take in a Perth Home?
Project run depends on project size, product spec and supplier
capacity. The supplier confirms the timeline at the quote stage. Full
walkthrough in our window
replacement Perth process guide.
Do You
Need Council Approval for Double Glazing in Perth?
Only for heritage-listed properties or properties in council heritage
areas. For most Perth homes, double glazing is a routine window
replacement not requiring development application. For State Register or
Local Heritage List properties, a development application to the local
council is required. Our heritage
homes double glazing Perth guide covers the process.
What
Warranty Should You Expect on Double Glazing in Perth?
Penot Double Glazing offers a 10-year frame warranty. For other
warranty terms, including IGU seal, hardware and installation
workmanship, ask at the quote stage. AGWA member suppliers typically
follow industry-standard positions on IGU seal and install warranty, but
confirm the specifics in writing before signing. Our how long does double
glazing last Perth guide covers warranty terms in detail.
Does
Penot Double Glazing Use Subcontractors for Installation?
No. Every installation is managed entirely by the Penot Double
Glazing team. No subcontractors are used. This keeps the certification,
the warranty position and the install quality consistent across
projects.
Will
Window Replacement Damage Internal Trims and Architrave?
The risk exists but is managed in the standard install process.
Architrave is typically removed cleanly for access, then reset or
replaced at the end. Where matching the existing trim is not possible
(old timber profiles no longer in production), the supplier discusses
options at the consultation stage. Painters can match existing wall
paint where touch-up is required.
Do You Have
to Move Out During Window Replacement?
No. The home stays occupied. Each room is opened and resealed within
the same day in most cases, with the home secure overnight. Furniture
near windows is moved or covered. Pets, kids and valuables need a plan
but the household functions through the project.
Comparison Questions
Is
Double Glazing Worth It for a Perth Rental Property?
For long-term holds, often yes. The energy bill reduction goes to the
tenant. The landlord captures the resale benefit (rising NCC standards
mean an upgraded property holds its market position better over time)
and the comfort benefit (longer tenancies, lower turnover). For rentals
being sold within 3 years, the case is weaker because the upgrade cost
is not recovered through resale in that horizon.
What
Is the Difference Between Toughened and Laminated Glass?
Toughened glass is heat-treated to be 4 to 5 times stronger than
annealed glass; when broken, it fractures into small relatively harmless
cubes. Laminated glass has two panes bonded with a PVB interlayer; when
broken, fragments stay bonded to the interlayer. Both are Grade A safety
glass under AS 1288:2021. Laminated is preferred for security
applications and acoustic performance.
Is Double
Glazing Worth It for an Apartment in Perth?
Yes when the apartment has west or unshaded north-facing windows,
when noise from the street or surrounding apartments is significant, or
when the building is targeting a higher energy rating. The complication
is the strata approval process: in WA, windows are typically common
property under the Strata Titles Act 1985, so the council of owners must
approve the upgrade. Our double glazing for Perth
apartments and strata guide covers the process.
Can You Double Glaze
a Heritage Perth Home?
Yes, with two paths. For State Register or locally listed properties,
the council development application process is part of the project.
Premium architectural aluminium systems with 45 to 65 mm sightlines come
closest to original timber sash proportions. Wood-alu hybrids preserve
the timber sightline on the inside face while delivering modern thermal
performance. Some State-registered properties require timber restoration
with secondary glazing instead of full replacement.
What Is
the Difference Between AGWA Members and Non-members?
AGWA (Australian Glass and Window
Association) is the peak industry body for AU window and glass
manufacturers, conducting compliance assessments of member companies.
Members commit to AS 2047 and AS 1288 compliance, the AGWA Industry Code
of Practice for Installation, and a Code of Conduct. Member warranty
positions are standardised. Non-member suppliers may meet the same
standards but do not carry the third-party audit and warranty
framework.
Is
Double Glazing the Right Answer for Every Perth Home?
No. Four cases where single glazing is the better financial decision:
planned ownership under 3 years and the home is on the market, windows
in good condition with favourable orientation, major renovation or
demolition planned within 5 years, or budget constraint where secondary
glazing on the worst rooms is the stepped alternative. Outside these
cases, the upgrade typically pays back through a combination of energy,
comfort, condensation prevention, acoustic and resale benefit over a
10-year horizon. Our hidden cost of single
glazed windows Perth guide covers the cost-of-inaction framing in
detail.
Where Penot Double Glazing
Fits
Penot Double Glazing is a full AGWA member based at 92 Beechboro Rd
S, Bayswater WA 6053. The standard double glazed windows and doors range covers thermally
broken aluminium frames, solar-control low-e and acoustic laminated
glass, and triple glazing for high-spec applications.
For a quote specific to your home, book a free in-home
assessment. Compare options across the double glazing Perth range, call 1300
121 603, or visit the Bayswater showroom.
