Views: 33 Author: Site Editor Publish Time: 2026-03-12 Origin: Site
You’ve invested in premium Low-E Insulated Glass Units (IGUs) to meet strict energy codes and LEED requirements. The glass looks perfect when it leaves our factory. But here is the hard truth: A high-performance IGU is only as good as its seal.
If the secondary seal is compromised during installation, you won't notice it on Day 1. You’ll notice it two years later when condensation (fogging) appears between the panes—at which point, the energy-saving argon gas has escaped, and the unit has failed.
As a manufacturer, we want your building to stay energy-efficient for decades. Here are the 3 critical things to inspect immediately after your IGUs are installed.
The black material you see around the edge of the glass is the secondary seal. Its job is to hold the two panes together and protect the primary butyl seal (the gas barrier).
What to Look For : Check for any notches, cuts, or smears in the silicone caused by rough handling or sharp metal frames.
The Risk: If the secondary seal is "shaved" or thinned to fit into a tight frame, it can no longer resist the pressure changes (pumping effect) caused by wind and temperature. This leads to seal failure and gas leakage.
IGUs are not designed to sit in water. If the window frame’s drainage holes (weep holes) are blocked or non-existent, the glass edges will be constantly submerged in rainwater.
What to Look For : Ensure the Weep Holes are clear of debris, labels, or excess sealant. Verify that the glass is sitting on proper Setting Blocks so it is elevated above the drainage path.
The Risk: Long-term water immersion causes "Chemical Attack" on the seals, causing them to detach from the glass surface. This is the #1 cause of premature fogging in modern buildings.
During the "pumping" of heavy glass into the frames, the two panes of an IGU can sometimes shift slightly (displacement), or be squeezed too tightly by the pressure plates.
What to Look For: Look at the Spacer Bar . Is it still perfectly straight and parallel to the glass edge? If the spacer looks wavy or twisted, the unit is under excessive mechanical stress.
The Risk : Excessive pressure on the edges can cause the glass to crack or create a "cold bridge" where the thermal performance is drastically reduced.
For a LEED-certified building, "Design Intent" is only half the battle. "As-Built Performance" is what matters. A single failed IGU can ruin the building’s thermal envelope and increase HVAC costs for the owner.
By spending 15 minutes inspecting these 3 details on-site, you can ensure that the premium glass we manufactured delivers the energy savings we promised.
Need technical support for your facade project? Our engineers can provide detailed glazing guidelines to ensure your IGU installation stands the test of time.
