I remember waking up as a kid on wintry mornings to find frost on my bedroom window obscuring the trees and yard.
Those were traditional six-over-six windows, with individual panes of glass secured between muntins. With newer construction and the advancement in double-paned window technology, window frost is not as commonplace as it used to be. But it still occurs in plenty of older homes, and while frost formations can be stunningly beautiful, they are not something a homeowner should welcome.
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. That liquid then freezes into ice crystals, and you've got your frost.
Frost can cause damage. As it melts, it transfers moisture to whatever is next to it. If that's a wooden window, it can discolor varnish and crack paint or even damage the wood. Frost can also melt off single-paned windows and seep down into a wall. If moisture is not handled swiftly and completely, mold can begin to grow.
Double Hung Windows. Photo: Crest Home Remodeling
So, how can you prevent frost?
- Weatherize your windows when it gets colder. Make sure storm windows are installed properly and caulk any gaps in the seals.
- Run a dehumidifier. If you can keep the inside air drier, frost will be less likely to form.
- Keep your home sufficiently warm, especially at night, to keep frost from forming. It might be worth putting a space heater in a room that is particularly prone to collecting frost on windows to see if that solves the problem.
- If all else fails, you may choose to replace single-paned windows with double-paned windows. The barrier of dead air between the double panes helps to slow down the transfer of heat/cold.
Being a responsible homeowner means letting go of some romantic ideas about nature, like the beauty of frost on your windows in the morning. But don't worry. If you're really missing nature's artwork, I'm sure you can find some on your windshield as you head out to work or the store!
For more on winterizing, consider:
Icicles: Charming or Chancy?
How To: Avoid Ice Dams and Water Damage
11 Ways to Winterize Your Home on a Budget