What Would Cause Handprints to Appear Inside My Double Pane Window?

Condensation

• Condensation is the process by which humidity in the air collects on a surface and converts into a liquid form. This happens most commonly in winter when the interior of your home retains humidity. Since it is cold outside, the moist air collects on the window -- the coldest surface it can find. When the air comes in contact with the window, it instantly cools down and is converted to moisture. If you have pressed your hand against the window, the water appears around the print. To see how this works, draw a picture on your bathroom mirror with your finger and take a hot shower. When you get out, the picture will be visible.

Reducing Condensation

• To prevent condensation from collecting on your windows and showing off handprints, reduce the humidity and increase the air circulation in your home. Avoid using devices, such as humidifiers, and increase your use of exhaust fans. Make sure that appliances, such as your clothes dryer, vent to the outside to release humidity outside of your home. If indoor humidity levels are still high, crack the windows for a few minutes each day to release some of the moist air.

Dust and Dirt

• When dust and dirt accumulate on a window, everything that touches it leaves a mark -- including your hands. It doesn't take much dirt to create a film on the glass that, in turn, leaves smudges and prints every time you touch it. Double pane windows are in no way immune to the effects of dirt and dust, so keeping the window glass clean is the key to preventing handprints from showing up.

Reducing Dirt

• To clean your double pane window, first scrub it with a sponge soaked in water and liquid dish soap. Always work from top to bottom so that you don't drip dirty water onto areas you've already cleaned. After wiping down the window, take a squeegee to it, pulling it straight down from top to bottom. Wipe the blade between strokes to prevent streaks -- if any remain when you're done, buff them out with a chamois.