💦 Waking up to wet windows

I woke up to find all of my windows covered in condensation.

Why it matters: Condensation can damage building materials.

  • Knowing when it will occur can inform how we manage the issue.

🤓 Nerd alert!

  • The good news is I won’t make you do any math.

🖼️ The big picture: Water condenses on a surfaces when that surface is at or below the dew point.

  • The dew point is a temperature that changes based on two factors.

👉 Air temperature

👉 Relative humidity

🙋‍♂️ Your weather app will tell you the current dew point.

🧮 By the numbers: Let’s use my house and the current conditions to unpack this.

  • When I woke up the outdoor temperature was 73 degrees and the relative humidity was 95% — yuck!
  • That makes the dew point 71 degrees.
  • My indoor temperature was 69 degrees.

🧐 So what happened?

  • With the outdoor temp so close to the dew point and my indoor temp below the dew point
  • The glass on the outer pane (my windows are double-paned) got to 71 degrees (or colder) and condensation formed.
  • With the high humidity in the air and the sun not yet shining on the windows
  • They can’t dry yet.

✅ For your Smart Homeowner list

😁 If you’re still with me, here are two takeaways.

  • Understand the dew point. Start checking the dew point on your weather app on humid days.
  • Paint your house—especially your siding—if it’s been more than 10 years since you last painted (or less depending on paint quality). Paint protects materials from moisture.



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