The Case of the Noise Nuisance
Dear Glass Detective,
My flat has two bedrooms directly facing a busy road. I am planning to replace the existing single glass windows with double glass windows to reduce the noise. Please advise if a single-laminated glass window may be more effective in cutting the noise than a non-laminated double glass window.
Thank you for making contact with the Glass Detective with your question regarding making the best selection for glass replacement to reduce the sound/noise coming through window openings in your home. You state that you currently have single-pane windows (two bedrooms that face a busy, and therefore undoubtedly noisy, roadway) and you want to make a wise selection when replacing them. You also mention that you plan “to replace the existing single glass windows with a double glass window to reduce noise.” You then go on to ask if single-laminated glass would be more effective at reducing noise than a double glass window. We frequently get questions of this type and the most appropriate way to answer them is to provide you with statistical information which almost always answers these type of questions. I will provide you with that, but first I think it is appropriate to also point out just a few other factors for you.
Typically, the thicker the glass, the more resistance to sound wave transmission. If you have single-glazed windows in your bedroom, it is most likely 1/8-inch thick glass. This thickness of glass will offer some resistance to sound but not a lot. Another consideration is the framing system that you are dealing with. Noise can also come through the walls of a building. Glass gets blamed for a lot of things, but it is usually only a part of the problem when talking about sound and energy issues. I have no doubt that a well-installed new window system is going to be of some help to you. Depending on the size of the window openings, the glass is certainly an important consideration also. Okay, now to the numbers that are going to be of utmost importance to you in making your final glass decision—here are generic averages:
|Unit Type||Unit Thickness||Glass Quantity and Thickness||Sound Transmission Class (STC)||Outdoor-Indoor Transmission Class (OITC)|
Single Pane Glass
Single Pane Laminated
|5/8-inch||2 x 1/8-inch||31||26|
Insulating Glass Unit
|1-inch||2 x ¼-inch||35||28|
Insulating Glass Unit (laminated and tempered)
|1-inch||2 x 1/4-inch||39||31|
Notes: Both the STC and the OITC methodologies are used to measure and compare sound transmission through given materials based on formulas previously established. So for our purposes, we need to look at these number in a comparative approach. For instance, based on the above, we could surmise that a single piece of ¼-inch glass is about the same as a 5/8-inch insulating glass unit made with two pieces of 1/8-inch glass and a 3/8-inch air spacer. However, as a comparison, a unit using just one piece of 1/4-inch laminated glass gives us an improved STC of over 25% and an improved OITC of over 10%.
I do need to point out to you that there are numerous combinations of glass (thickness of components and overall thickness of an insulating glass unit). Your window supplier can help you make the right decision. There is no doubt however, that laminated glass will help reduce sound transmittance whether used individually or as part of an insulating glass unit. On a personal note, there are other factors that should be considered as well in your situation. For instance, laminated glass provides some amount of protection from weather and vandalism because it will tend to hold together in the opening when broken. It is also ultra-violet light (UV)-resistant. You will want to compare product pricing when making your final decision. The laminated products will cost a little more but are usually well worth the additional costs.
The numbers referenced above are industry averages and are not necessarily from any manufacturer. They may vary from manufacturer to manufacturer but I think they are representative enough for what you are working on and I hope they are helpful to you. Thank you again for contacting the Glass.com Glass detective and we wish you well with your project.