Stop Frosty from Coming

In the winter, we often found our windows covered with frost, come morning time.  If it's super cold, the frost is thicker and covers more surface.  It's a nuisance, because as the sun rises, that frost melts, and we find pools of water on the window pane and sometimes dripping down to the carpet.

Why does this happen, and how does it happen?  You see, we close the shades for the night, and that traps warm, moist air between the shades and the cold glass surface of the windows.  Low winter temperatures, especially at night, first condenses that air, then freezes the condensation (i.e., water). 

Of course we could leave the shades up during the night, and that would solving this annoying chemical phenomenon.  But we want to have privacy in the evening, for instance, while we're having dinner and watching TV.  Also, we want to be energy conservative, so the shades serve as a barrier to keep the cold temperatures out. 

My end in mind à la The Core Algorithm was to come up with a solution that balanced energy conservation and nuisance avoidance.  (By the way, my wife would go around to each window, place towels on the pane, and later wipe everything off.  To me, that was annoying.)

Walking backward to map the pathway, I reasoned that if the so-called culprit of the frost was condensation, then I had to find a way to stop that from happening. Of course the heat from our house furnace would keep the warm, moist air as gas, and thus prevent the change to liquid or solid.

Once I knew what we had to do to serve our end, the third and final step was simply to do it, that is, walk the pathway.  Instead of leaving the shades up, I rolled them down and kept a one-inch gap above the window pane.  It took a few tries to find the minimum gap to completely prevent frost on the windows.  Also, by keeping the gap to a minimum meant, we used just a little bit of energy (heat) to serve our end.

This last step was an empirical process of adjusting the gap, so we could avoid the frost and conserve energy in the most optimal balance. 

One last thing, winter air inside our house could get so dry that our skin flakes, itches, and sometimes cracks.  So we had a central humidifier installed, and the air was noticeably more comfortable for us.  But I realized that I had it set too high: I released too much moisture in the air, and that contributed to the condensation problem.  By dialing it down, I helped to avoid the frost and conserve energy with an even better balance.