I just had my windows professionally cleaned, but still see streaks or dirt on my windows.
This can be a problem, for some homeowners when the window seal begins to fail. This is a common problem for aging windows. A failed seal around the insulated glass unit allows moisture to get in between the panes which can lead to condensation and the glass looking foggy, wet or dirty as well as degrading the insulating ability of the window.
What causes the seal to fail?
As the glass expands and contracts with weather, it causes the seal to fail, creating moisture in the windows. In between the panes, is low- E and argon gas. Low-E coating is applied to window glass to help reflect heat and adding argon gas between the panes of glass adds increased insulation to the window. A failed seal will “oxidize” the low-E coating and argon gas, making the glass appear streaky or foggy.
How to repair the broken seal?
The window may need to be taken off site or can be repaired at your home by a specialist. However, not every window will qualify for repair. A homeowner should weigh the cost to repair the seal versus replacing the windows. Newer windows use a glazing bead space that helps hold the glass in place, but moves with the glass, to eliminate the issue. I contacted one local company and they repair the broken seal on site and offer a 10 year warranty and offer a free onsite estimate.