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One of the biggest causes of heat loss for RV owners who camp or live in colder climates is single-pane windows. In this article I’ll share some ways I added extra insulation to our camper’s windows to prepare for living in our camper during the winter months. (To read about other ways we prepare our RV for winter, click here.)
Here’s a little anecdote to illustrate how much heat is lost through the windows of our fifth wheel: this year I was a bit lazy about getting the windows done, and one day recently I was sitting on the couch and felt a bit chilly. It was around 32 degrees Fahrenheit outside, but the thermometer/hygrometer on our fridge read 75. I moved the thermometer to the shelf I built behind my sofa next to the window, and half an hour later thermometer read 66. At that point I knew I’d better get a move on with my window project!
Last Year’s Window Insulation
A lot of people cover their RV windows with Reflectix, but as sunshine is extremely important to me, especially during winter, anything that would block light wasn’t going to be an option for me.
Instead, I decided to use shrink plastic, which I had used in homes before. If you’ve never used it before, basically you put double-sided tape (included in the kit) all the way around the window frame, then cover the window with plastic stuck to the tape, and then you blow a hair dryer on it and the plastic shrinks and all of the wrinkles smooth out and the seal around the edges traps a layer of air between the plastic and the glass; this air is actually what provides insulation agains the cold.
Shrink plastic for windows works great. In fact, I ended up leaving the shrink plastic on my hall windows all year since I always leave the shades in the hall down anyway to try to keep the sun from beating directly in on my hall thermostat. (Additionally, I added reflective window film to my hall windows to help with that problem.) In spite of my love for shrink plastic, though, it does have a few problems:
- Some RV owners have trouble getting the tape to stay stuck to the window frame due to condensation and have to use a sturdier type of tape. We did not have that problem, however.
- Applying shrink plastic to all of the windows in an RV is a tedious, time-consuming task. It sucks to have to do it each winter.
- Our cat inevitably ends up tearing holes in the plastic with his claws, and by the end of the winter my window is covered with clear tape patches.
After covering a few of the windows with shrink plastic last year, I became impatient with the process and decided to try another method for insulating windows against the cold: bubble wrap. To cover a window with bubble wrap, all you have to do is dampen the glass with water (I used a wet rag) to stick the bubble wrap to the glass, bubble side facing the glass. Just water will most likely keep it in place, but if it comes down you can simply dampen the glass again and stick it back up. I also used Scotch tape in a few places, like to tape two pieces of bubble wrap together.
The bubble wrap method is very easy, but not very classy looking (IMO), and you can’t see out a bubble wrap covered window, so I ended up only using bubble wrap on a few of my windows that I didn’t mind leaving covered with the sheer shades all winter, like on the side of our house that faces our neighbors’ front yard. One of those windows, the one behind my husband’s desk, is actually still covered with bubble wrap that I never took down over the summer.
Also, I didn’t find the bubble wrapped windows to be quite as well protected against cold as the shrink plastic windows due to the bubble wrap having perforated spots with no bubbles. So I don’t plan to do bubble wrap again this year.
I did use one more window covering method last year, just for a few of my screen windows, and that was to make clear vinyl covers attached with Velcro. I did this so that I could remove the covers and open the windows on nice days. This method worked pretty well, and since the vinyl was sturdy, my cat didn’t tear it up. There are a couple of drawbacks:
- The vinyl I used (heavy clear shower curtain liners) had creases in it that made it not look very good. If you buy clear vinyl on a roll at a fabric store, this wouldn’t be an issue.
- The Velcro doesn’t make an airtight seal, so it might not be ideal for extreme northern climates (but it’s fine for us in Kansas City).
Even with those drawbacks, I decided to reuse this technique this year.
This Year’s Window Insulation
My strategy for covering my windows this year is as follows:
- Shrink film on the hall window (leftover from last year)
- Bubble wrap on the window behind my husband’s desk (leftover from last year)
- Plexiglass on my big windows.
- Vinyl covers attached with Velcro on my screens and smaller windows.
And now for a little more detail….
Plexiglass Storm Windows
I would just cover all my windows with plexiglass if I could afford it, but it’s kind of expensive (for me), so I decided to use it on three of my four big windows (the fourth being the bubble wrap window). I purchased three 24″x48″ sheets from Lowe’s at about $30 apiece, and I had it cut at the store, but, as you will see, I ended up having to cut it myself also.
Here was my process:
After unscrewing and removing my window shades and curtains and cleaning my windows with a microfiber rag wet with water, followed by a dry microfiber rag (which beats Windex at streak free glass cleaning, by the way), I held up the plexiglass to the window I planned to cover…and immediately realized I had forgotten to take into account the curved corners of the window. After watching a few YouTube videos, I learned how to cut plexiglass using a utility knife (razor blade). You can actually buy a tool designed especially for cutting plexiglass, but I didn’t really want to make another trip back to Lowe’s, so I decided to try the razor blade method, and it worked just fine for my purposes.
First I used a Sharpie to mark where I needed to cut. Then I scored the mark several times with the utility knife over an old cutting board.
And finally, I grasped the corner with a pair of needle-nosed pliers and easily broke it off.
I sanded the edge so it wouldn’t be so sharp.
It’s really best if you have a helper for this.
To adhere the plexiglass to the window frame, I used my favorite invention ever, clear acrylic mounting tape. This stuff is super strong, yet very easy to remove if needed. It also works when it’s wet, as I learned when I used it for a project in my shower, so it should work even for people who have a window condensation problem. Update: after using it for a project on the outside of my RV, I learned that this adhesive also works in sub-zero temperatures, as long as you heat it slightly (I used the palm of my hand) while applying it. I wrote an entire blog post about all the ways I’ve used this double-sided tape.
Unfortunately the plexiglass didn’t come in a size that was tall enough for my window, so I ended up with about a two inch gap at the top. I covered this gap with a strip of clear shower curtain vinyl adhered with the mounting tape.
It doesn’t matter, though, because that part is always covered with my pull-down shades.
Here is the plexiglass on one of my other windows:
The emergency exit latches protruded out too far for the plexiglass to cover on this window, so I used a strip of clear vinyl along the bottom the same as I did at the top of the other window. It should be very quick and easy to remove in case of an emergency.
I really love how the plexiglass storm windows turned out. They look like they came that way. I will may get plexiglass for a few more windows next year.
Velcro Vinyl Window Coverings
I made clear vinyl covers adhered with Velcro for the screen parts of the windows I covered with plexiglass so I could remove the covers and open the windows to let in fresh air on nice days.
Last year I made two vinyl window coverings, but only one was able to be reused this year because I didn’t do a very good job of storing them and the Velcro came unglued and made a sticky cat hair magnet.
I actually decided to go ahead and use the one above since it was going to be mostly obscured by plants anyway. Then I made new ones, too.
To make the covers, first I cut 1″ Velcro with scissors so that it was 1/2″ wide and stuck it (both the hook part and the loop part together) to the window frames.
Then I cut a piece of vinyl a little bigger than the space I needed to cover and stuck it carefully to the Velcro, stretched as taut as possible to avoid creases along the Velcro.
Finally I trimmed the edges with a utility knife.
For this smaller window, I decided to cut the vinyl big enough to cover the entire frame, because on my windows where only the inner frame is covered the outer frame still gets pretty cold. It doesn’t look pretty, but the shades and curtains hide most of it.
So that’s how I winterize my windows for cold weather RVing. Please leave a comment if you have any questions! And if you would like to see the rest of the things we do to prepare our camper for winter, you can read about it in this blog post.
Update 12/6/17: I still have one window that I haven’t insulated yet because I open it to let my cat in and out of our camper, and the other night after boiling some water on the stove I noticed it was covered with condensation while all our insulated windows were completely dry! We don’t typically have a problem with humidity (whether because of our climate or our RV design I don’t know), but the boiling water had raised the humidity in the house, and evidently the single pane window was cold enough to cause condensation to form, while the other windows were not!
Update 1/4/17: We have had some really cold weather this past couple of weeks–colder than what’s normal for Kansas City, with lows below zero and highs in the single digits, so I have been able to really see which types of window coverings are the most effective. Here are my conclusions:
- The plexiglass is definitely the best. It looks great, and the windows are noticeably warmer.
- I ended up using bubble wrap on the other two windows to the left and right of my husband’s desk because I was too lazy to do more plastic, and it is actually more effective than I remembered. But, you can’t see through it, so I still don’t like it as a solution for all my windows (although it’s better, in my opinion, than Reflectix, since it does let light through).
- The shrink plastic isn’t a bad solution, but it’s a lot of work and not as effective as plexiglass.
- The vinyl covers are the least effective, I think because the Velcro doesn’t create a seal. They are still a lot better than nothing, but you can see in this photo below that quite a bit of frost still formed on the part of the window that was covered with vinyl (the part with the screen), while the part covered with Plexiglass (without a screen) hardly has any frost at all:
One RV owner suggested using magnetic strips instead of Velcro to create a better seal; if anybody tries that, let me know how it goes.
Also, I have seen quite a few pictures of RVs with the windows insulated from the outside, and that seems to be the most effective solution of all–just more work to put up and take down.
To do this, these RV owners covered their windows on the outside with Reflectix or plexiglass taped on with foil HVAC tape, which can be used at any temperature and comes off cleanly when removed. I actually think clear vinyl would work really well for this purpose. Bubble wrap probably wouldn’t work as well, as the perforations would allow moisture to get inside and trapped next to the window.
Click here to read about the other ways we prepare our RV for winter!