Why There is Ice on the Inside of Windows & What to Do About It
Waking up to a freshly fallen sparkly blanket of snow can be a magical (if inconvenient) experience, but waking up to a thick layer of ice bordering the inside of your windows? Still sparkly, but much less magical…
My grandpa tells of waking up with snow on his bed when he was a little boy — but that was nearly 100 years ago. Haven’t we figured out how to keep ice and snow out of our houses by now? (I’m making light, but please know you have my deepest sympathy if your home is unable to keep the winter weather at bay.)
I know how lucky I am to live in a sealed, insulated, and heated house, even with the occasional indoor-ice! We’ve been trying to find a solution to this situation that doesn’t involve me blow-drying the windows every morning, and here’s what we’ve learned so far..
Why Is This Happening? The American Society Of Home Inspectors Reporter has an amazing breakdown of all of the forces at work, complete with amazing diagrams, and they explain it a thousand times better than I ever could. If your windows are icy, I recommend starting here.
Use A Dehumidifier This seems counterintuitive, as we generally think of winter as a dry season, with the use of indoor heating increasing the dryness immensely. However, it seems an excess of humidity is definitely possible, and can be a major contributor to indoor ice. Modern homes are often extremely well-sealed, meaning all of the moisture created by making tea, cooking pasta, taking showers, and exhaling stays within the house and condenses on the cold windows.
Use Your Exhaust Fans According to the now defunct Minneapolis StarTribune’s FixIt column, “Another way to increase ventilation is to operate bath and kitchen exhaust fans part of every day to expel excess” moisture. This is in addition to the time the exhaust fans are used when bathing and cooking. Be sure that exhaust fans blow directly outside and not into attic space.”
Seal All Joints The University Of Wisconsin’s AboutTheHouse suggests, “A temporary solution may be to carefully seal all the joints of the prime window where the sashes meet the frame with rope caulk, which is removable in the spring. Alternately, you could install a plastic film over the windows, making sure to wrap it around the frame. In the spring, remove the sashes and check the weatherstripping. The manufacturer should be able to supply you with replacement weatherstripping, if needed.”
Open The Curtains/Blinds PGT Industries has several suggestions, including “Opening drapes and blinds, allowing air to circulate against windows.” This one is tricky because we like to keep the curtains closed at night for privacy and insulation, but I’m willing to give it a try.
Increase The Heat I’m trying to keep my heat as low as possible, but according to Bob Vila, it’s important to “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.” Who am I to argue with Bob Vila?
Check Your Ventilation Settings I’m not entirely sure what this means, but Making Houses Work says, “If you already use mechanical ventilation and have low interior humidity, but are still having problems, you may need to examine your ventilation setting. If you have a heat recovery ventilator (HRV), it may be recirculating too often, which can contribute to increased moisture build up in the air. Recirculation mode closes the connection to the outside and brings exhaust air back into the rooms…and keeps the HRV core defrosted and saves energy, but it is also possible for it to run for too long.”
Keep The Windows Cracked ARE YOU KIDDING ME? Almost every source I consulted casually recommended keeping the windows open a crack, blissfully unaware that our nighttime temperatures have been in the -11ºF (-23.89ºC) range lately. I would be so cold and so broke if I took that advice!
Have you been battling to keep the winter out of your home? How have you fared?