Convection occurs when air gives up its heat to the cooler glass and sinks toward the floor. This movement sucks new, warmer air toward the glass that is in turn cooled, creating a draft. What you are actually experiencing is the process of warm air forcing colder air to move due to differing density properties. Heated air circulates through the home. When it reaches window glass it effectively pushes the existing cold air off the glass.
How Does Convection Work?
Windows may seem “drafty” due to a process known in physics as convection. Convection can lead you to believe that your windows are drafty when, in fact, they are not.
Try This Easy Experiment to Experience It!
Fill a glass with ice and water. Let it stand for about ten minutes. When you return, place your hands around (but not touching) the glass. You will feel cold air on your hands as warm air pushes it away from the glass surface. Convection is actually proof that your new windows are energy efficient and working well
Tips to Reduce Convection
To reduce the presence or frequency of window convection in your home, there are some things you can do. Leave your blinds or curtain slightly open to encourage warm air reach the glass. If you have a small office fan, you can put it in a bay window or a garden window to encourage air movement. Promote a warmer glass surface and that cycle will not be as pronounced. Make sure heat registers are not blocked by tables, couches, or other furniture. Get good air flow and equalize air temperatures throughout the room.