How do I keep my glass doors from fogging up?

Glass doors in refrigerators and freezers are prone to getting condensation on them. For businesses such as floral shops, supermarkets and convenience stores, this fog on the glass is unattractive and obstructs the customer’s view of their products and may reduce impulse buys.

Why do glass doors get condensation?

An important fact to keep in mind is that warmer air is able to hold more moisture than colder air. The “dew point” is the temperature at which the air becomes saturated and can’t hold any more water vapor and some of the water vapor must condense into a liquid form. The dew point is always lower than (or equal to) the air temperature. For example, glass of ice water will begin to sweat in a warm room because the air coming into contact with the glass is cooled to the dew point. This will cause the air to lose its capacity for holding moisture and condensate will stick to the glass. The exact same thing happens when the colder surface of your glass doors meets the warmer air in your building.

How do I fix this problem?

You may find that wiping windows down a few times a day may be all that is required, but this is not a permanent solution.

1. Adjust your thermostats.

Try slightly raising the temperature in the walk-in cooler. This will also raise the surface temperature of the doors, possibly to a temperature that will not cause water to condense on them. If that doesn’t help, you may also try lowering the temperature in your building. A colder setting on the air conditioning may help to pull more moisture from the air near your walk-in cooler. You may also try using a dehumidifier in your building to help remove excess moisture in the air.

2. Replace damaged components.

A damaged door gasket could let in warm moist air into your walk-in. This air will cool to the dew point and lose its excess moisture which will create fog. If you have heated doors, a foggy door could indicate your heater wire needs to be replaced. Some heated glass doors have anti-sweat controllers that may not be working properly.

3. Buy new glass doors.

If you are in the market for new glass doors, consider getting a model with heated glass or an anti-fog coating. In high humidity conditions, these coatings will cause condensation to form a clear layer instead of droplets that give the appearance of fog. Major manufactures such as Anthony and Styleline offer models of glass doors designed not to sweat. In addition, newer doors are generally better insulated which will cause the surface to be less cool and less prone to condensation buildup.

External Source: http://weathersavvy.com/Q-Science_Dewpoint.html