What standard double glazing does for noise – By Edinburgh glazing experts
Standard double glazing involves two panes of glass separated by a sealed air gap, usually filled with argon gas.
The spacer that holds the glass panes apart maintains the seal around the double-glazed unit, and that combination gives you drastic improvements over single glazing on both thermal performance and noise reduction.
Sound waves lose energy as they cross from one pane of glass through the air gap and into the second pane.
A well-sealed standard double-glazed unit can reduce the level of noise entering your home by around 30 to 35 decibels compared to single glazing.
But not only that, standard double glazing reduces higher-frequency external sounds well, including voices, wind, and lighter passing traffic.
Where standard double glazing runs into difficulty is with low-frequency noise.
Traffic noise from main roads and motorways travels at frequencies that pass more easily through two glass panes of the same thickness.
Same-thickness glass panes vibrate at the same resonant frequency, and at that frequency sound transmission is at its least disrupted, so those low road-noise frequencies pass through with less resistance.
How acoustic glazing is different
Acoustic glazing uses a specialist glass rather than standard float glass for at least one pane in the double-glazed unit. It can be attached to a uPVC, timber, or aluminium frame.
Acoustic glass is a form of laminated glass: two layers of glass bonded together with an acoustic PVB interlayer.
PVB stands for polyvinyl butyral, a resin film that sits between the glass layers and is designed to dampen sound vibrations rather than allowing them to pass through.
The key to acoustic performance is the glass thickness.
Acoustic laminated glass is made with different thicknesses of glass on each side of the acoustic PVB interlayer, and that asymmetry is deliberate.
By using different thicknesses of glass in the unit, acoustic glazing disrupts the resonant frequency problem that limits standard double glazing.
Sound waves hitting glass panes of different thickness don’t transmit through as cleanly, and the acoustic PVB absorbs what gets through.
Acoustic glass can reduce external noise by around 40 to 45 decibels in a well-fitted unit, compared to 30 to 35 for standard glass.
That 10-decibel improvement in acoustic insulation is roughly equivalent to halving the perceived loudness.
For homes on quieter residential streets, standard double glazing may be all you need for noise control. For homes within earshot of a main road, railway line, or airport, specialist acoustic glazing is likely to make a meaningful difference to comfort.
Thermal performance: does acoustic glazing give anything up?
No. Acoustic glazing doesn’t sacrifice thermal performance to achieve better acoustic properties, and the two types of glazing are comparable on energy efficiency.
Our standard double-glazed units achieve a U-value of 1.4 W/m²K, with additional glazing options allowing your windows to achieve values as low as 1.2 W/m²K!
Both glass products, standard and acoustic, perform at this level within a well-sealed uPVC frame with an argon fill.
If reducing heat loss is the primary goal, our triple-glazed windows achieve a U-value of 0.8 W/m²K.
For homes where both noise and heat loss matter, acoustic glass within a triple-glazed unit is possible. That configuration gives you the thermal insulation of three panes alongside the acoustic properties of the PVB interlayer.
This helps increase comfort, reduce noise, and reduce your home’s carbon footprint.
Frequently asked questions
Is acoustic glass worth the cost?
For homes near busy roads, railways, or airports, the improvement in acoustic insulation is substantial enough to make a practical difference to how comfortable your home is day to day. For quieter locations, standard double glazing provides plenty of noise reduction without the additional cost. A poorly fitted frame undercuts even the best acoustic glass, so who installs it matters as much as what they fit.
Does acoustic glass reduce condensation?
Acoustic glass doesn’t significantly change condensation behaviour compared to standard glass. Condensation on the inside of a window is usually a ventilation issue in the room, while condensation on the outside surface is a sign of good thermal insulation in the glazing unit and is perfectly normal. A well-sealed double-glazed unit of either type handles internal condensation better than single glazing, because the inner pane stays warmer.
Should double-glazed windows be soundproof?
No glazing unit is fully soundproof. Both standard and acoustic double glazing significantly reduce the level of noise entering a home, but some external noise will still be audible, particularly at high volumes or close range. Acoustic glazing brings the noise level down far enough that it stops interrupting sleep, conversation, and concentration, even if it doesn’t make the road disappear entirely.
Get the best noise reduction for your home with The Advanced Group
We supply and install noise-reducing windows across Central Scotland, with acoustic glazing options available across our uPVC range in casement, tilt-and-turn, and sash styles.
Our double-glazed windows start at 1.4 W/m²K as standard, and our experienced fitters can advise on whether standard or specialist acoustic glazing will give you the peace and quiet you’re looking for.
We’ve been fitting windows and doors across Scotland since 1988, and we offer a free home survey with no obligation to buy. Flexible 0% finance is available on all installations.
Call us on 01355 271 223 (Glasgow) or 0131 370 0444 (Edinburgh), or book your free home survey online.
