Do you have window condensation or frost? Did the weather suddenly get cold?

If you have wondered whether window condensation correlates with a sudden snap of cold weather, take a look at this chart. The inset chart shows Chicago temperatures for the week of November 18-26, 2013. Note the big temperature drop on Sunday. Now look at the traffic on Window Condensation: Top 10 Fixes during the same period. There was about a 500% increase in web traffic from earlier in the week.

Window condensation increases when temperature drops
Web traffic for article “Window Condensation: Top 10 Fixes” plotted against Chicago temperatures. The temperature dropped from 30 deg to 12 deg from Friday night to Sunday morning. Web traffic increased about 500%

It happened again in cold snap #2

To show you this isn’t a fluke, it happened again. The temperature in Chicago suddenly dropped between December 5 to December 7, 2013 from 57 deg F to 9 deg F. A 48 degree drop in only two days! No wonder we Midwesterners are hearty and resilient, or is it stupid for living here?

The second Chicago cold snap in 2013 produced the same web traffic results as the first one
The second Chicago cold snap in 2013 produced the same web traffic results as the first one. As temperatures dropped, people scurried to search online for solutions to their window condensation problems. And our article “Window Condensation: Top 10 Fixes” was waiting with useful information.

It happened again in cold snaps #3 and #4

On January 3rd we had a baby cold snap at around 0 deg F, but it was enough to show up on our analytics. But when the mother of all cold snaps happened on January 6 and 7, with temperatures around minus 15 deg F, our traffic on the window condensation article broke records at around 200 page views for each day. Time on page for the first ten days of January topped 5 minutes per view, which in our ADHD society equates to moving in with suitcases and staying overnight.

Chart of temperatures of historic cold snap of January 6 and 7, plotted against web traffic of https://www.https://www.https://www.https://
When the historic cold snap occurred in Chicago, and much of the rest of the US on January 6 and 7, people flocked to https://www.https://www.https://www.https:// to read “Window Condensation: Top 10 Fixes”

Was it only Chicago?

Thanks for asking and of course not. The cold wave swept North America. Our analytics told us the regions that sent us the most traffic, so we plotted it on a chart for your edification:

States experiencing low temperatures sent readers to our window condensation article for help. Looks like the folks in Minnesota were too frozen to read the article once they found it
Many states experiencing low temperatures sent readers to our window condensation article for help

Why does window condensation and sudden cold weather go together?

When temperatures are moderate, the air is capable of holding much more water in a vapor state, so the outside humidity is elevated. This moisture makes its way inside through the building envelope. When the temperature suddenly drops outside, the elevated humidity inside the building changes to a liquid state when it comes in contact with the suddenly cold windows, wetting them. This is condensation formation on the windows.

Window condensation can subside after you remove some moisture from the inside environment by wiping the windows dry, and then when the inside air dries further because the outside air becomes dryer.

Condensation can seriously damage wood windows. Don't let windows get wet
Interior condensation on wood window sash (left) can cause the paint to peel and even rot the wood itself (right). It is important to be proactive to avoid condensation damage to windows

Aluminum windows can have more pronounced condensation on the frames because frame temperatures are often lower than on wood windows. Aluminum windows do not tend to self-destruct the way wood windows can, however condensation overflow can harm adjacent finishes such as wood floors and drywall.

Condensation on aluminum window
Aluminum window frames can get colder than wood frames, so they often show a greater volume of window condensation.


To be proactive in controlling window condensation, read this article:
Window Condensation: Top 10 Fixes

Outside humidity and comfort

Your comfort in cold weather is also related to outside humidity. Before the cold snap, you could be really cold outside in 30 degree weather because the water vapor air in the air carries the heat away from your body much more readily than does dry air. After the cold snap, the outside humidity is much less, so it carries your body heat away less. You can feel warmer in 20 degree dry air than in 30 degree humid air. Sounds like people from Phoenix who proclaim the merits of dry heat whilst they shrivel to a prunelike state.

Then there’s the effect of the wind, but that’s yet a different subject.
Read about it here: Wind Loads and Windows for the Very Windy City

Very cold weather causes window condensation
Mark Meshulam, Chicago Window Expert knows what it means to be COLD!

7 thoughts on “Sudden Cold Snap Coincides with Window Condensation Web Traffic”

  1. Great information. I have a one year old, 2400 sqft custom built home in SW Ohio w/ geo-thermal heat. The interior humidity is approximately 55 to 60 per cent. The window condensation as you well know is terrible. The HVAC installer has stated my only recourse is an HRV unit at a cost of $2500. I understand the condensation issue. Last winter & again now, all my Marvin Integrity windows are not only dripping water, they are frozen shut. No offers an explanation to the high amount of humidity in this home. With your experience, have HRV units proved to an effective solution to condensation issues in new construction homes.
    Thank you. Your efforts to provide sound and useful information are appreciated.

    Jerry Stichter

  2. Hello Mark,

    I live in the Maritimes in Canada. I had casement windows installed in my house two years ago, but I never noticed the window leaking before because I had the TV in front of the window. Since I changed everything in my living room I now sit in front of the window. There seems to be a draft, and lots of icing on the bottom of the window. On a few days that the outside temperature was -25 with with the wind. The temperature at the bottom sill was 2.9 degrees Celsius and the top sill was 13 dregree Celsius. Which seemed a little strange to me. So I then took the temp of inside the window pane, which was reading -o.1 at the bottom and 6 at the top of the pane.. I called the company to come over to see what is wrong and all they said was that since we had thick drapes , that there was no heat getting to the window,. I kinda find this weird because there shouldn’t be a temperature difference on 10 degrees. They are vinyl windows. Have any recommendations ? Thanks

  3. We have a very busy and full retail store in a historic building. Our hvac is shared with a retail “service” with lots of open space at the front and electronic equipment at the very back. (The historic building is now subdivided, but used to be one retail space.) We have lots of customer traffic and our staff moves around at a frenzy, creating heat. Their side is opposite, with lots of sitting. All seasons, we are hot and they are cold. The thermostat is located in a hallway, which measures neither spaces accurately. We attempt to keep the t-stat set at 70 degrees year round, which is really too hot on our side. When the outside temps get in the 50s or lower at night, our neighbor wants to keep the heat on, set at 65 degrees, as she said any different causes condensation on the inside of her windows. (We actually have photos which show heavy condensation with her desired setting.) With this, our temperatures quickly rise to 76-78 degrees. I have suggested a space heater for when she gets cold, but she refuses because of the electric draw. There is a lot of animosity. Our landlord is elderly and doesn’t want to invest much money. I like dealing in facts. What needs to be done? Is turning on the heat the correct request on her part? Any advice is appreciated.

  4. Mark Meshulam
    Your info really shows how educated and experienced you are!
    Yesterday to my horror on the stucco in back of the house has black stains coming down from the corners of aluminum windows. These two-paned aluminum windows ice up so much covering almost entire window in freezing weather.
    Moved here summer of 2016 and were not any markings then. Until what I had seen yesterday!
    Please help with any suggestion/s you might have.

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