Doors and Windows - What is a standard I.G. unit? help anybody?

Hi. Am going to replace my windows. Salesman suggest to use an Insulating glass unit. What are the specifications of a standard IG unit in terms of glass thickness of each lite, spacer size, and is it tempered normally or just an option? Can I assume that if the thickness is say 1/8" per lite that the glass has a combined breaking strength of say the usual 1/4" single glass that I have on right now? Help anybody? Thanks

It is difficult to answer your question.

I'm assuming that your salesman is recommending you remove your current windows, and replace them with some sort of commercial style aluminum glazing system. This seems unusual, but if these windows are going into a cement or stucco house, then I understand why.

As far as "standard IGU", I don't think there is such a thing, and even if there was, if you are replacing your current windows, you will want custom measured IGU's so that you don't have "filler" around your window opening. You can literally get any kind of glass you want. The most common is double strength.

You can order low-e, low-e2, bronze, argon or krypton filled, double pane, triple pane, aluminum spacer, swiggle spacer, the list goes on and on.

The thickness of the IGU will depend on the glazing system it is being installed into. 1" is the most common commercial thickness, while residential window IGU thickness varies from 7/8" to 13/16" to 3/4" or even 1/2". Tempered glass is an option that is available on any IGU. Code requires that glass that is within a certain distance from the floor be tempered, so you might check the codes in your area to see if it is required on any of your windows.

Replacing bedroom windows with IGU's would surely be against every fire code that I know of, since there are fire escape egress laws that must be taken into consideration.

I'm sure that I don't understand exactly what you're doing, but it sounds a little odd, so I'd recommend getting a 2nd opinion from another window salesman.

Thanks for the reply. I guess I was a little vague in my original question. Maybe you can help me if i am more specific. I am contemplating changing my present lousy aluminum windows with 1/4" single pane glass to a vinyl window system with double glass I.G. unit. Since I am working with a budget I was told that the most economical standard I.G. unit to be used with the vinyl windows consists of two equal 1/8" annealed glass and 1/2" aluminum spacer dry air type. Upgrades include Lowe coatings, argon filled and tempering but these addtional charges puts me precariously over my budget. My concern is , a friend said taking energy savings aside, my present 1/4" single glass is still stronger (more resistant to breakage) than using the two separate 1/8" glass in an I.G. unit. Is this true? We have quite a few vandals roaming our area with penchants for throwing whatever objects like empty beer cans and the likes when thay feel like it. Thanks for the anticipated enlightening response

It is very unusual to have 1/4" glass in "old single pane aluminum windows". Most were glazed with single strength glass and at best double strength (1/8"). If you use 1/8" glass in your new windows it will give you a bit more protection against "empty beer cans" at a small increase in cost. If vandalism is your main concern then you'll have to spend the extra buck for laminated or Safe-T-View™ (a plastic film attached to one surface on the inside of the insulating glass unit.

I cannot imagine having 1/4" glass in any residential application. That is surprising....although I have seen glass that thick in a few jealousy (and I spelled it wrong!) in South Florida.
Any dual or triple pane window is by definition an IGU. It simply means insulating glass unit. As XSleep and Johnam suggested, there are a number of options available for a "standard" IGU.
I am guessing, but I suspect that the salesman meant standard to mean exactly what you said, a bare bones product without upgrades.
If you are going to the expense and trouble of changing your windows though, you might want to consider at least one or two available upgrades, depending on where you live. A simple IG unit with an aluminum spacer might be fine in some locations, but in severe heating or cooling climates you might have issues with these windows when they are installed.
Double strength glass is 1/8" or 3mm. Single strength glass is 1/16" (or a bit less). Single strength is quite common on IGU applications, but some companies, for example Andersen, heat strengthen all of their single strength lites. This makes the lites about twice as strong as a normal single strength and very comparable to a double strength product.
Under teh circumstances with the vandals in your neighborhood, an upgrade to tempered might be worth the extra trouble.
I am curious how many companies you have talked with and what company specifically you were dealing with for this particular quote.
I am guessing that you are in either Florida or Texas from your descriptions...

Over 90% of all new windows in North America are built using IGU's. Windows using IGU's (with the potential for certain options, of course) certainly meet every code requirement in North America from impact resistance to energy efficiency.

Thanks guys for the enlightening responses. I know what questions to ask the salesman now and hope can get a good bargain for good windows. Will not hesitate to post some other questions if the need arises.