Outside condensation

Condensation on the outside of your windows or patio doors may occur during Spring and in the Fall, usually when cool nights follow a warm day. It is a result of moisture in the air exceeding certain limits and the temperature of the glass falling below the dew point in the air.

Condensation on the exterior glass panes is a natural phenomenon.  It evaporates as the day warms.

Inside condensation

Condensation on the inside of your windows is a result of too much moisture in your home’s air. This condition is common in new homes, where it may take months for the moisture from paint and fresh building materials to dissipate.

This condition is also common in winter. Humidity levels in winter months should not exceed 30 – 35%. To maintain these levels in your home, you may want to:

• Use a dehumidifier to remove excess moisture

• Turn your humidifier or furnace down or off

• Turn on exhaust fans during showers

• Allow ceiling fans to circulate air

When using window shades

When window shades or blinds are employed over a window they provide a second insulating space equivalent to or greater than the insulation provided by the insulating glass unit. This causes the temperature of the interior glass surface to drop significantly.

This produces two effects. First, condensation and ice may form on the lower  surface of the window. Second, because of the large difference in temperature between the glass surface and the back surface of the shade, convection currents are set up and cold air will “fall out” from the bottom area between the window and the shade. You may feel this cold air coming out from beneath the blind or shade and think the window is leaking.  (This condition can be worsened by the use of accordion or thickly insulated blinds.)