Acoustic windows in steel: Realistic RW gains and glass options

• 14 October 2025
• News

We live in a world of noise. Everything from the pinging of mobile phones to the constant roar of passing traffic has the potential to disturb, and noise pollution is an increasing challenge in both residential and commercial environments. From traffic and train lines to busy city streets and neighbouring properties, unwanted noise can affect comfort, concentration and quality of life. For many construction and residential clients looking to minimise noise pollution, acoustic performance of windows and doors is as important as energy efficiency or architectural style.

Crittall has been a pioneer of steel windows for more than 175 years. Our frames are celebrated for their slim sightlines, durability and timeless aesthetic. When combined with carefully selected acoustic glazing, they deliver high levels of sound insulation while maintaining design integrity. Steel’s strength allows larger expanses of glass, maximising natural light while reducing noise intrusion in both homes and workplaces.

Understanding R_W values

RW refers to Weighted Sound Reduction Index, a measure of how effectively a window blocks external sound. The “weighted” aspect reflects the human ear’s sensitivity to different frequencies, giving a practical sense of how much quieter a room will be by applying a weighted correction factor.

For example, if external noise measures 70dB and the target indoors is 35dB, an RW of 35dB is required. Every 10dB reduction is perceived as roughly half as loud, and a 20dB reduction feels like a 75 per cent drop in sound energy to the human ear. Even modest improvements can significantly improve comfort and peace of mind.

Acoustic windows in practice

Noise reduction glass works by disrupting sound waves. Standard double glazing provides some insulation, but effective soundproof windows require acoustic glazing. Laminated panes, varying glass thicknesses and optimised spacing between glass panes reduce sound vibrations and limit noise intrusion.

Crittall steel frames, particularly the thermally broken T60 system, combine precision manufacturing with acoustic glazing. Our iconic black steel windows offer the same slim sightlines and strength with a distinctive aesthetic suitable for contemporary homes, commercial offices and heritage properties. The result is a window or door that retains architectural integrity while achieving high levels of sound reduction.

Glass and frame options

Different glazing solutions provide varying levels of noise control:

• Standard double glazing achieves approximately 30dB RW, suitable for quieter residential streets.
• Acoustic double glazing with laminated panes featuring an acoustic laminate  delivers up to40dB RW, effective near traffic, railway lines or properties in conservation areas.
• Triple glazing achieves up to 43dB RW or more, often used in high-noise environments such as meeting rooms, offices adjacent to train lines, restaurants or high-end urban apartments.

The thickness of the glass, the cavity between panes and the frame construction all influence the level of noise reduction. The T60 system accommodates acoustic glazing up to 36mm thick, achieving reductions of up to 43dB. Black steel windows offer similar acoustic performance and can be specified across residential and commercial projects to maintain consistency of style.

Setting realistic targets

Practical benchmarks help define expectations:

• Bedrooms benefit from internal noise levels below 30dB for restful sleep.
• Living areas should aim for less than 35dB.
• Commercial spaces such as meeting rooms or offices often target 40dB  to ensure speech privacy and minimise unwanted noise.

Steel window frames also improve energy efficiency, helping to reduce energy bills and support year-round comfort. Multipoint locking and high-quality hardware increase security, while slim Crittall sightlines preserve character and maximise daylighting.

Tailored acoustic solutions

Every project is unique. Crittall works with homeowners, architects and developers to specify acoustic windows that balance style, heritage, energy efficiency and sound reduction. Steel French doors,  and bespoke configurations ensure consistent performance across homes, office spaces, hospitality venues and heritage restorations.

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