Why Is There Ice On The Window?

A few weeks ago, we faced the coldest temperatures we’ve seen in 2 decades. Here in St. Louis, I hunkered down to wait out the cold. I pulled all the cellular shades down as tight as I could to block out the cold air once the sun headed down for the night. The Next morning was bright and sunny, especially with all the snow we’d had just in front of the arctic cold. I raised the shades on the sunny side of my place and was greeted by ice on the window frames and creeping into the middle of the window panes. Wow – that was one I’d not seen before. I knew my metal frame windows were not as good as in my previous home and this was definitely testament to that.

Cellular Shades And Ice On The Window

I realized the blinds had trapped the cold and moisture. I opened the blinds on the windows east to west as the sun traversed the sky and fortunately the sun helped heat up the windows to melt the ice and dry the windows. I opted to repeat the procedure for the next subzero night knowing I would need to dry the windows in the morning. Indeed, the windows and blinds performed as expected.

After doing a bit of research, I found the issue of ice on the window discussed on a variety of blogs and sites. The simplest remedy is to leave the blinds raised slightly. But then they don’t insulate as well? And I’ve been quite happy with my blinds’ ability to keep my place cooler in the summer and warmer in the winter, especially knowing my windows are not so great. So, I’ve opted to keep,the blinds closed tight knowing that on those few subzero nights (and days) I will just need to be prepared for some ice on the window and to dry them once the sun gets going.

This occurrence reiterated the differences that we experience between different types and quality of windows. It also demonstrated how effective my cellular blinds are – they really cut down on those cold drafts one often feels close to windows on cold days and nights.

For me, the blinds have allowed me to postpone new windows – which will be a much larger investment than the blinds were. Just knowing and understanding one’s home is a good starting point to finding remedies to fit the situation and budget.

Want to learn more about your homes windows and energy efficiency? Simply log into your HomeNav account (or sign up for a free account here) and navigate to Windows via the Feature Types Section, found on your dashboard.

2 Comments… add one
Bruce McCunney, AIA January 16, 2014, 3:13 pm

The problem with keeping those blinds shut tightly when ice will build up on the inside face of window is that, when the window warms enough to melt the ice, if there is enough moisture on the inside, some will drip down to finishes (drywall, paint, wood trim, etc.) and could eventually be detrimental to them.

Don Dieckmann, Better Building Institute January 17, 2014, 8:13 am

Another tip about blinds and extreme cold weather: Instead of opening them a little or at the bottom, open them at the top (if you can) and/or angle them to point upwards on the inside, so that any warm air behind them will rise into the room, and the cold air will sink to the bottom of the window, instead of into the room. A ceiling fan pulling air up and across the ceiling will help circulate not just the air in the room, but also the air behind the blinds, reducing the humidity there, and hence the ice. Try it – it works in most cases, and best of all if you have wooden blinds.

Leave a Comment