At Windsor Windows and Doors, we understand the needs of homeowners and have included some useful information here to help you care for your windows. Most homeowners assume that condensation is the fault of the windows. In fact, moisture collecting on the interior surfaces of window glass is an indicator of high humidity within the house. The humidity within a home will be attracted to the coolest surfaces, such as the window glass. The humidity represents itself as condensation.
Humidity is water vapor mixed with the air within the house.
You cannot see it, it is invisible. It is invisible until it shows itself as condensation on your windows. Condensation usually occurs on the windows first, because they have the lowest surface temperature of any other interior surfaces within the house. The temperature of the window glass will be substantially colder than the rest of the house in winter. Humidity will increase near the glass as the temperature decreases.