Why Windows Fog Up

The Problem

99% of the time moisture occurs inside a window, not because of a failed seal, but solely due to the cycle of “solar pumping.


The inner airspace of a window gets heated by the sun or ambient air during the day. The glass flexes outward minutely, pushing some of the hot air through the semi-permeable seal to the outdoors.

In the evening, the airspace cools. The glass returns to its normal position, drawing small amounts of air back into the cavity.

The air drawn into the window from the atmosphere naturally holds moisture. The moisture is absorbed by the window spacer’s desiccant material.

When the desiccant is saturated and can no longer absorb, fog will show on the glass. The moisture continues to accumulate turning the fog into condensation. If left for too long, minerals in the moisture can get baked onto the glass causing staining. These stains get thicker and eventually etch into the glass causing permanent damage.

The Solution

Our service is performed on-site with minimal inconvenience to the customer.

Dual pane, Triple pane, Low E coated and Heat Mirror windows can all be saved, but time is of the essence!

The All About Windows Defogging process is done with the window on the building and is backed by our limited lifetime warranty.