The boulevard is deafeningly noisy, neighbors argue loudly, and on the other side of the street, there is an echoing yard of a school or kindergarten. In such situations, we rely on the internal spaces to protect us from the noise and commotion, so that we can work and rest properly. Along with good insulation of the external walls, windows play a crucial role in ensuring silence. Today, windows are produced using technologies that guarantee excellent insulation against both cold and heat, as well as external sounds. However, in extremely noisy environments, special soundproof windows are needed.
Loss of health, life, and money
Noise is one of the most underestimated health hazards nowadays, according to the World Health Organization. Noise in the urban environment causes up to 16,600 cases of premature death each year in Europe, according to the European Environment Agency. More than 900,000 cases of hypertension can be attributed to noise. It also leads to insomnia and cardiovascular diseases. Almost 20 million people in the EU experience "discomfort" due to noise pollution, and another eight million suffer from disrupted sleep, according to the EEA. Overall, harmful levels of traffic noise affect one in every four people in Europe.
A report from the European Commission as early as 2011 stated that noise from road and rail traffic costs 40 billion euros per year in terms of decreased property values near noisy roads, healthcare expenses, and lower labor productivity.
Soundproofing with insulated glass units
The insulated glass unit plays a crucial role in dealing with noise. Several of its characteristics determine its ability to provide silence in the interior.
Different thicknesses: the difference in glass thickness plays a leading role. When the thicknesses are not the same, the glass impedes the transmission of sound waves. This "kills" the sound waves. A double-glazed unit can be an effective sound insulator if its glasses have thicknesses, for example, of 5 and 6 millimeters.
Triple instead of double: the number of glasses also helps reduce the transmission of sound waves. They can, and it is desirable, to have different thicknesses as well. A classic scheme is 4-6-4.
Laminated glass: laminated glass is a specially developed weapon against noise. They are also known as laminated or triplex glass. A transparent "film" made of non-glass material is placed between the two glasses. It is elastic and "damps" the sound vibrations. A popular type of film is PVB (polyvinyl butyral), but other specially developed formulas are increasingly being used. At Rollplast, laminated glasses are made from Guardian's Sound Reduction series.
Interestingly, laminated glass not only provides sound insulation but also enhances safety. When broken, it does not shatter into separate cutting pieces, and thanks to the film, all glass pieces remain together, thus preventing the risk of injury.
Gap between glasses: the larger the gap between the glasses in the unit, the less sound can penetrate from the other side.
Argon: when the unit's cavity is filled with argon gas, it further reduces sound transmission.
Usually, these measures are sufficient to ensure satisfactory sound insulation in the interior. Sound penetration is reduced by around 32 to 40 decibels.
For spaces that need to be exceptionally quiet in an extremely noisy environment—for example, a peaceful hotel located next to an airport—special window system design is required. Naturally, this also burdens the budget.
It is important to know that the insulated glass unit accounts for over 90% of the sound insulation of windows.
Profiles for Silence
And the best glazing cannot guarantee silence if it is installed in an unsuitable frame. The material, construction, and installation joint should not be underestimated.
Material: Wooden profiles, besides creating coziness, are renowned as the best sound insulators. Multichamber plastic windows also have excellent properties.
Aluminum windows require significantly more effort to limit the transmission of sound from the surroundings to the interior. Their choice is justified when specific architectural and design features do not allow the use of wooden or PVC windows.
Overall, regarding sound insulation, the difference between wooden and plastic windows is insignificant. The choice is influenced by other parameters such as price, aesthetics, and personal preferences.
Profile width: The wider and more multichambered the profile is, the less chance there is for sound vibration to pass through fully, and external sound to be heard inside. Additionally, the reinforcement should be thicker. It is recommended to be around 2 millimeters.
Installation joint: The gap between the wall material (concrete, brick) and the window frame is a potential "breakthrough" point for sound. It should be sealed with "installation tape." Otherwise, moisture and noise can penetrate through it unhindered.
Sound Insulation Index
An indicator of the noise insulation level is the sound reduction index "R." It describes the degree of sound insulation provided by building elements.
To determine the level of silence a new window can provide, we need to look for the Rw coefficient, which represents the sound insulation of the entire window. The higher the number, the better the parameters.
Increasing Rw by 5 points will reduce the perceived sound power passing through the window by half.