Wild World of Windows

Our house had a pop quiz today. It was the type of test that no cramming session could help.

We signed up for an energy audit through Boulder County because our house can sometimes get a bit cold - as in ice on the inside of the windows cold.

Will & I were both hoping and dreading (hoding?) that windows would be a culprit in our arctic living room. We would love to change up the look of the windows, but we dread the hefty price tag. But if we could justify it in the name of energy efficiency… well, that might convince us to make the change.

We learned that our windows have an R value insulation rating* of 1 which sounds pretty tragic. However, most walls in houses the age of ours (built in 1961) have an R value rating of 10. The fanciest of fancy energy efficient windows only gets up to an R value of 5. And if those fancy windows aren’t installed and sealed properly they will perform about as well as our R value 1 windows.

Our windows were installed well and have aged gracefully with very little air leakage. A little bit of caulk here and there and we should be in good shape. By adding the honeycomb blinds on our big windows, we’ve actually increased the insulation quite a bit already.

And for the ice on the windows? Nothing really to be concerned about. The ice is a result of condensation on our single pane window. There is a heat vent about 3 inches in front of this window. As the hot air comes out of the heater it hits the cold glass and water condenses. When the temperature outside is frigid (the high on the day this photo was taken was -2 degrees), the condensation ices over.

We also learned that most windows aren’t as drafty as people might think. If you’ve ever sat in front of a window and thought you felt a breeze, it isn’t necessarily coming from the outside. When hot air hits a colder surface like a window the hot air rises against the window and cools. That cold air then falls down toward the floor. This creates air movement called the waterfall effect but it doesn’t necessarily mean that the window is drafty.

We don’t yet have the final results back from our energy audit test, but I’m guessing that the windows got a passing grade. Now the insulation in the attic? That slacker needs a tutor to pass any future tests. But I’m sure we can help.

*R value insulation ratings measure the ability to resist heat flow. The higher the R value the more effective the insulation is.