sound proof windows

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sound proof windows

#1 Post by jonchaley »

I am interested in replacement windows that provide sound deadening. I have read enough to understand that STC ratings are the industry standard for measuring the sound abatement qualities of windows, and that this is acheived mostly via a large air gap between the outer and inner panes on insulated glass. I also want a laminated glass window for hurricane protection. So, my ideal product would be a laminated insulated vinyl window witha 4" air gap. I can't find one. Any help? Thanks.

Dean S
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#2 Post by Dean S »

4" air gap? That's four inches?

The STC rating is important and the higher the better but keep in mind that your wall is probably has an STC rating in the high 30's. With laminated glass you can get ratings into the 30's and you can get windows into the 40's with two panes of laminated glass and energy panels. If you can get an STC rating in the high 30's you'll be fine. Also note that no window is sound proof.

You should also be concerned about the DP rating. A cheap window will not stand up to high winds and most cheap windows do not get checked for a DP rating.

Make sure both the STC and DP ratings are done independently, not by the manufacturer.

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#3 Post by jonchaley »

Thanks for the reply.

I'd like some feedback on who has the best quality windows for sound deadening purposes-most effective and best quality. I live in central Florida and I know all windows are not available across the country.

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#4 Post by jonchaley »

Oh, I'd also like opinions on window construction and type. Because of the humidity here, I'm thinking vinyl or fiberglass contsruction...anybody know which is better? Also, is casement type the best for sealing out noise?

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Sound Control

#5 Post by JScott »

Last year we installed Milgards Sound Control double hungs. We as well as the homeowner were pleased with the results. You can combine different glass options to get STC ratings in the mid 40's. Another low line manufacturer either Republic or Silverline have these as I remember an add in one of the professional magizines as Milgards are not distributed to Florida to my knowledge. The units have an extra set of sashes. The double hungs have an outer sash set and an inner sash set. The frame width is 5-1/4 which will work with brick but may protrude in siding. To open the window for ventilation you have to open a sash then reach in and open the outer sash. Warning: they were costly at $1200 each so the homeowner only had the STC units installed in their bedrooms so they could sleep at nights. In other areas of the home we increased the glass thickness to obtain STC in the mid to high 30's. Laminate glass will also help as you indicated you want the glass protection. Most of our manufacturers would like your first born to help pay for the upgrade to laminate. We had 1 service issue after installation on the positive action locks. We contacted Milgard and they(this plant at least) had us a retro install clip which resolved the issue within 2 weeks. Took about 1 minute to install and they sent instructions for installation. After thinking about the above I wonder if you couldn't install two units with the narrow 2 and something inch frames to achieve the same results for a lower cost(just trying to be creative, its' been a nothing went right kinda day). Hope this information helps. When we first saw the units we were in awe. From a U value perspective the values are also something to awe at. The cost as I said wasn't an awe but a ole my lord. They do work and work well. When the guys picked them up to install into the openings they also said ole my lord. The suckers are heavy. They made the heavy fiberglass units feel light.

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#6 Post by Guy »

The STC ratings will pretty much stop after your spacer goes over 7/8". If it gets bigger than that you will even decrease the decibal protection at certain levels. Almost every window maufacturer has a sound glass to offer any customer. Most IG (insulated glass) units are made up with single or double strength glass that sandwich a spacer. These are single sheets of glass on each side. Sound glass goes another step from there and makes the exterior side a double strength-double layered laminated glass. So now the outside glass alone is two layers of glass with a laminate inbetween them. This is very similar to the glass on your vehicles windshield. Like Jscott said this makes these windows incredibly heavy and painful to hang. I know Simonton, Republic, Windsor, Gorrell, Gilkey and Champion all have versions of sound glass. Most of the others carry some type to go with their product. A good piece of sound glass will be at least an inch wide in overall thickness. Hope this helps!

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#7 Post by jonchaley »

Thanks for both of your inciteful replies.

J Scott, you are correct that Milgard does not operate in Fla., however, your idea to simply install a second window in the same opening is a good one, especially in view of the fact that my current windows are fine. There is an outfit called Soundproof glass in Ca. that specializes in that and will ship direct anywhere. That would leave the laminated glass as the inner pane, but still a lot cheaper than the Milgard you quoted.

Guy, thanks for the names of some companies that actually make this kind of product. I will check the web sites for distributors in Fla. and let you know the results.

As a side bar, it's amazing how difficult it is to find out good information via these companie's web sites. Even when you call them, you are routed to a recorder, calls are dropped, etc.

One more question: any opinion on Hurd, PGT, or Pella? All are prominent here locally and I'd like to buy a product that's easily available, if possible. Lastly, is there any real difference, based on Guy's description of an acoustic window, between that and a standard insulated hurricane window, which is basically a laminated glass with an airspace, then a regular pane of glass?

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Sound proof and hurricane protection

#8 Post by Oberon »

Good thread.

Jonchaley, you are after the best of both worlds. Basically, if you want hurricane protection, you want laminated glass. If you want sound abatement, you want laminated glass. How easy can it be?

Actually, it gets better. For maximum sound attenuation (deadening) you also need a tight, heavy window sash and frame. It really doesn't matter how good (or expensive) the glass is if the frame is not up to the same standards. But, when you buy an impact rated product, you are buying an entire window unit that has been tested and certified to some rather stringent requirements and the window systems is about as tight as a window system can be.

There are five basic types of impact (hurricane) products available made with any of these systems can have DP ratings of 45 and upwards. Commercial and some residential windows made with the stronger materials have DP ratings well over one hundred.

First, is polyvinyl butyral or PVB. This is the same stuff that is in the windshield of your car, only the PVB interlayer is either .090" or .100" thick versus the PVB layer in a windshield is .030" thick.
PVB does a very nice job of sound blocking and is generally the product of choice when designing for sound.

Second, a few companies offer the PVB with a sheet of PET film sandwiched between two layers. This product is a bit stronger than ordinary PVB, but it is also quite a bit more expensive.

Third, some laminators offer a product called SGP or Sentry Glass Plus. This is a .090" interlayer that like PVB is laminated between two lites of glass, but it is about 100 times stiffer and has about 5 times the tear resistance of PVB. But, this product is costly. Many of the major window companies offer an SGP option, but often it is an upgrade for really large windows. This product is used extensively in larger commercial windows because of its resistance to stress due to its stiffness.

Fourth are the liquid resin laminates. A number of companies offer these products in Florida (and somewhat elsewhere). The difference in these versus the previous three is that the PVB and SGP are sheet goods laminated to the glass using a pressure and heat system.
The resin products are liquids that cure either thru chemical reaction or else by exposure to UV light.
Several of the resin laminators also use a sheet of PET in their product for additional strength.

Finally, are the glass / plastic hybrids. These are generally a sheet of Lexan (polycarbonate) laminated between two layers of glass using a urethane to bond the materials.
These units are incredibly strong, but they have a tendency to distort in high heat / sun because the polycarbonate has a different coeficient of expansion versus the glass.

As I said, all of these options are available to you in Florida. There are also the aftermarket films, but I didn't mention them for several reasons...I will say that they offer no sound advantages and leave it at that.

STC, or Sound Transmission Class is the measurement used to determine the ability of a window (or wall or door) to attenuate sound...that's the simple part. Unfortunately, it becomes a bit more complicated.

I am going to offer a few examples, but please bear in mind that there are other factors affecting the sound performance of a window besides just the glass.

A single sheet of glass has an STC of 30. Simple as that. But, below about 250hz, the specific sound transmission loss of 21db or decibels. At 2000hz, that same lite has a transmission loss of about 35db. See the relationship? Although the overall is STC 30, the sound performance of the unit is best at 2000hz. After that, the performance starts to decline.

As humans, we are born with the abilty to hear from 20 to 20,000hz. By the time we are teenagers, we have lost the ability to hear much over 14,000hz.
We hear low frequency sounds best. Low frequency sounds travel the furthest (notice the base on kid from down the street's stereo as he drives past your house?)
So, notice that the poorest performance of the single lite is in the lowest part of the spectrum?

When constructing an IGU (Insulating Glass Unit) for sound abatement (beyond the normal), the manufacturer will do one or more of several things.
They will increase the width of the airspace, they will make the two lites in the IGU of different thickness, and/or they will use laminated glass.

I have to run off for a bit, so I will add more to this later.

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#9 Post by jonchaley »

Guy- just to let you know, Champion does not offer windows in Fla.

Gilkey seemed like the highest quality. If anyone's heard different please say so. All of their contact list is in the Cincinatti area, though.

Simonton and Windsor will be worth a closer look, while the web sites for Republic and Gorell are either confusing or lack any specific technical data.

Oberon-thanks for the education on laminates. I didn't know there was such a wide range. Still, you have essentially confirmed what I originally thought: that laminated, insulated hurricane glass is a good sound deadener also. I wish there was a product that provided this with a large air gap as you indicated, but right now I can't find one. The biggest seem to be ony about one inch. I have read some specs which suggest a minimum of 100 mm (about four inches) is the minimum air gap for good sound abatement, but so far only the California outfit "Sound Proof Windows" offers that, and only because it fits on the inside of your existing windows.

Anyone know where I can find more than a one inch air gap for insulated hurricane windows?

Thanks to all of you for excellent and timely feed back.

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#10 Post by Oberon »

You're welcome, but I am curious what your specific need is for that sort of gap? I suspect that you will probably need to use something like the sound-blocking panel that was mentioned in order to get that sort of construction, ultimately.

A few numbers for comparison:

The lite I mentioned in the previous post was 1/8" btw...I forgot to mention that. Also, I can spell "bass" as in musical instrument, but I was a bit rushed when I was finishing that post...

The following figures were derived by the Riverbank Acoustical Laboratory and were determined from transmission loss data based on requirements of ASTM E413 (there goes the official disclaimer!)...

A monolithic laminate 1/8 x .030 x 1/8 = STC 35

1/2 IGU -- 1/8" x 1/4"AS x 1/8" = STC 28 (AS = airspace)
change one lite to the laminated make up mentioned and the STC is 35, the same as the monolithic laminated lite. Note the numbers as related to the 1/4" air space?

1-1/2" IGU -- 1/8" x 1" AS x 1/8 = STC 37
kick the airspace up to 4" and the STC rises to 44, or leave the AS at 1" and change one lite to laminate and you have an STC of 42.

If you were to change both lites to laminated and use the 1" airspace, your STC would be 46.

Finally, if you were to use a 4" airspace with two laminated lites, you would achieve an STC of 53, which is a heck of a lot better than your typical wall.

Again, with the understanding that these numbers are based totally on IGU performance and that actual performance in the field will be extremely dependent on the construction and especially on the quality of the installation of the window....and also that STC is an "averaged" figure and does not relate to specific performance at specific frequencies. It is entirely possible that a window with a higher STC of one particular make up might not perform as well as a window with a lower STC and a different make up at blocking specific sounds or frequencies.

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#11 Post by Janis »

I am contemplating Stanek windows for my home in FL. I read in their brochure that their Heat Mirror System 6 & System 9 provide EXCELLENT soundproofing. (I write this and am reminded of Joe Pesci in My Cousin Vinny! I hope you are in a better spot than he was! LOL!)...

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#12 Post by Windows on Washington »


WOW!! Great posts guys. A ton of good info in here. Thanks.


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