RV Windows in Winter

Condensation on windows is an ongoing challenge for RV dwellers when the temperature falls. I understand that those with thermopane windows have less of a problem, but I wouldn't know firsthand; we're not so lucky.

This is our second winter in the trailer. Both years have been in mild-winter areas (cool, moist winters with rare snow and quite a few nights that just dip below freezing, plus a couple nights as low as 24F). So, we're not talking severe cold here, which we wouldn't stay around for in this non-four-season trailer. Even so, perhaps what we've learned will be helpful to others.

Last winter, which we spent parked at our daughter's house, we had to to a lot of window wiping, a couple times a day, saturating several terry cloths (we buy those bundles of white terry cleaning cloths and have a plastic shoebox-size bin of them handy for whatever). Water would pool in the bottom channels of the windows--a couple of them have those little  slot-shaped drains, but not all. I had to soak it up with a terry cloth. We had the free use of our daughter's washer and dryer, and even so, getting them dry and ready for the next round of wiping was an ordeal.

This year, we have to ante up five quarters for each and every load of washer or dryer use (we're lucky; it's higher a lot of places). Hanging the cloths up to dry isn't a good idea, as it adds to the humidity problem. So it seemed a good investment to apply the do-it-yourself plastic window film kits to see if it would help. We have three ceiling vents we can open for ventilation, and I also left the sliding window over the sink un-filmed.

The difference was dramatic. In the morning, there is some beading along the bottom edge of the window. It's important to run the cloth along there first thing in the morning, before the droplets break loose and run down the wall. I can do the whole trailer with one cloth.

I'm still trying to wrap my head around the physics of condensation. I know it has to do with warmed air meeting cold air and all that, so the next thing we discovered surprised me. I thought bundling up the windows would help, so we would faithfully close both the pleated shades and the curtains, which resulted in what you see above plus some moisture higher up. One night we forgot to close the pleated shade, and with just the curtain, there was much less condensation to wipe. Since then, we close only the curtains at night, leaving the pleated shade open.

The kitchen window, which we did not apply the film to, looks like this in the morning.

This is what all our windows looked like last year. Plus, there is that little pool in the bottom channel of the kitchen window.

It seems, though, that every time we solve one RV living problem, there's another one. Partway through winter we discovered that there was some mold growing behind the film where we can't get at it to clean it. We just sighed and added that to our list of spring chores.

So I'm going to follow through on an idea I had about how to make removable interior storm windows from sheets of acrylic. That way they can be taken down for cleaning and replaced. I won't be getting around to that until the end of summer, most likely, but I'll share with you how it goes.