Why Windows Fail
Double pane and triple pane windows consist essentially of glass panels with spacer bars between them that make up the frame. The air trapped between the glass panels provides insulation, which increases the "R" value of your home or business.
The air between the window panels naturally heats up and cools down with atmospheric changes. Known as "solar pumping," the air expands when heated; when it cools, moisture is drawn inside the space. Excess moisture is absorbed by desiccant materials contained within the spacer bars, keeping the proper balance for thermal insulation.
When the seals between the glass panels and the spacer bars are compromised, the window is said to have "failed." Too much moisture is allowed into the air chambers, the desiccant material becomes saturated and fog or condensation appear inside the windows. The quality of the spacer bars or the adhesive used to seal them to the glass may be to blame, although lack of maintenance can also contribute.
Two styles of spacer bars are typically used in thermal window frames:
- The Swiggle Seal is a patented S-shaped plate covered in a black rubbery compound. The compound contains a foam version of silica desiccant that absorbs moisture drawn inside during the solar pumping process.
- Aluminum spacers contain single or double lines of perforation down the center of each bar. Silica pellets inside the aluminum bars absorb moisture through the perforations as solar pumping occurs.
When fog or condensation appear inside a thermal window, the moisture threshold has been reached. This condition can be prevented or repaired if caught in time.
Maintenance can help significantly extend the life of window seals, and caulking is a key factor. Regular inspection of caulking outside the windows, with reapplication as needed and possibly painting, as well, can help preserve the life of internal seals. Poor seals outside lead to more moisture inside, and condensation collected on internal seals will weaken them. When seals fail, silica materials reach their saturation limits, and condensation occurs.
At the first sign of condensation inside thermal windows, contact Window Medics for window repairs in London and across Southwestern Ontario. We can repair damage and prevent future problems with our exclusive one-way valve technology. Call us today!