Reduce Moisture. The reason why your storm door/window is icing up is most likely because the moisture in the warm house air is getting colder. When this happen, the air can’t hold as much moisture, so it will cling to the door and freeze.Click to see full answer. Also question is, why do windows get ice on the inside?Frost forms on windows when they are exposed to cold air on the outside, moist air on the inside. Moisture in the room’s air (water vapor) is drawn to the window pane, and when the outside surface temperature lowers past the dew point, that water vapor solidifies into liquid. why is my storm door freezing up? On cold winter days when the interior house door is open, hot air hits the cold storm door, causing the window to frost or steam up. If the storm door frosts all the time, though, even when the interior door is not open, it indicates too much warm air is hitting the storm door on a regular basis. Just so, why is my front door freezing shut? The problem occurs when water vapour leaks through the exterior door, causing ice to build up in the locks and inside the jamb. Moisture present in the home will normally only cause problems like the ice buildup if there is too much or it is allowed to cool.What causes condensation on a glass of ice water?When water vapor in the air comes into contact with something cool, such as the outside of a cold glass of lemonade, its molecules slow down and get closer together. When that happens, the gaseous water vapor turns back into liquid water droplets. That’s condensation!