An insulated glass unit, or IGU, is two panes of glass (or occasionally three) connected by a spacer, and sealed together. This makes a double pane unit that is found in a large number of window systems. If your window looks foggy, or you are seeing moisture between the panes, that is a clear indication that the seal in your IGU has failed.
Any IGU is going to fail, given enough time. That's why most glass shops will provide a 5-10 year warranty on their IGUs. After that point, they accept the fact that their units will fail.
We don't accept that. We've worked to find the best materials we can, and have put together a superior product. Let's look at why that is.
An IGU, as I said, is composed of three components: the glass, the spacer, and the seal. When it comes to glass, there's not a lot of variance as to the quality. We offer good glass, but anyone else will do so, as well. So, that leaves us with looking at the spacer and the seal. These are where the difference lies.
Most companies use an aluminum spacer. This is functional and affordable, but has issues. Aluminum, like any metal, will expand and contract with temperature fluctuations. In an environment like we have here in St. Louis, those fluctuations can get rather extreme. Over time, that repeated expansion and contraction will cause the seal to fail, or in the worst case, can even crack the glass.
Instead, we use a structural foam spacer. This has a couple of benefits. It maintains its size through temperature fluctuations. It's not a piece of metal against the pain of glass, so it's not going to break the glass. And it has a desiccant incorporated into the material, to help draw any moisture out of the air.
For the sealant, the most common options are silicone or butyl. Silicone is a reasonable option, but doesn't provide the most long-lasting seal. Butyl is a cheap and easy alternative, but is fraught with issues. It is applied by melting it and injecting it into the area around the spacer. The problem with this is, again, the temperature variations here can be extreme. The heat of summer will cause the butyl to melt, compromising the seal.
Our sealant is a polysulfide blend. This is a two-part material that sets with a chemical reaction, so heat is not going to effect it. That means, that over time, the seal will stay intact.
So, because we use a superior spacer and sealant, our company provides a lifetime warranty on all IGUs we assemble and install. Our units shouldn't fail, but if for some unforeseen reason they do, we will make it right!