The short answer
- Truly soundproof windows do not exist. Every window transmits some sound, so the goal is choosing the glazing build that cuts the noise you actually have.
- Noise reduction comes from mass and asymmetry, not from the frame. A basic single-pane unit is the weakest build and a laminated multi-pane unit is the strongest.
- Pairing two different glass thicknesses in one unit, such as 4mm with 6mm, stops both panes resonating at the same frequency and is the cheapest real improvement.
- An acoustic laminated interlayer is the biggest single upgrade. Add it to one pane for traffic noise, or to both panes for flight paths and adjacent freeways.
The STC tiers.
STC 28-32: single-pane and basic double-pane. Reduces normal conversation to faint. Insufficient for urban traffic, aircraft, or busy street.
STC 35-40: standard double-pane LowE IGU. Reduces normal traffic noise to ambient. Suitable for suburban street and moderate urban density.
STC 40-45: asymmetric-thickness double-pane (e.g., 4mm + 6mm) with acoustic-PVB laminated on one lite. Reduces highway and intermittent aircraft to comfortable. Standard hospitality spec.
STC 48-52: laminated double-pane both lites, or triple-pane with laminated outer. Reduces flight-path aircraft and adjacent freeway to background. Premium residential and high-acoustic hospitality.
STC 52+: requires laminated triple-pane, often with mass-loaded interlayer. Specialty acoustic and recording-studio spec.
Common questions.
- What STC rating do I need?
- Most residential applications target STC 35-40 (standard double-pane) for suburban quiet. Urban or arterial-street locations target STC 40-45. Flight path or major highway target STC 45-50. Compare against the outdoor noise contour at the project site.
- Are triple-pane windows quieter than double-pane?
- Modestly. Triple-pane adds roughly 2-4 STC over equivalent double-pane through more mass and a second cavity. For pure acoustic gain at lower cost, asymmetric laminated double-pane outperforms triple-pane.
- What is the quietest window I can buy?
- STC 50+ requires laminated glass on both lites of a double-pane or laminated triple-pane construction. Acoustic-PVB interlayer (versus standard PVB) adds another 2-3 STC. STC above 55 typically requires a secondary interior window assembly.
Keep reading.
Project in motion
Acoustic spec on your project?
We build to STC 28 through STC 56. Specify the target STC at quote and we will return the glass build that hits it.