Dear Dave,
I have just arrived to work in a pretty cold climate. Winter will be over soon. However, right now it is still fairly cold, with frost on the windows. I have noticed here that some folks have insulation types on the exterior of the windows and some on the inside. Any thoughts, other than leave for Florida? lol! Thanks. —Andrew
Dear Andrew,
I have not used any window insulation that is applied to the outside other than a windshield cover. It was not really for insulation, but rather to protect the windshield and cover better than those stupid curtains! But I have used several products on the inside.
Blow dry plastic
These residential window insulation kits are easy to apply and allow you to still see what’s outside. Place the two-sided tape around the frame and apply the film. Trim it close to the tape and then use a blow dryer to shrink the film. It acts as a dual pane window and the air gap between helps insulate. You can get them in different sizes and weight material.
Reflectix shiny cell foam
This is a popular product for cold weather camping but is not as easy to install as it needs to be cut to size and typically fastened with tape. I have, on occasion, used Velcro strips so I could take the material off when not camping in the cold. You need to leave an air gap with this, as well. It will reflect 96% of the radiant energy that strikes it. Most RV windows are not sealed very well at the edges or sliders where the two glass pieces meet. This helps dramatically. However, you cannot see outside the window.
Quilted shades
One other item I have found is quilted covers or shades. These are custom made and can replace the existing blinds or shades, or applied with Velcro. Again, these block the view and make it darker inside. However, I have found that in the dead of winter there’s not much to look at anyway.
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.
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Dave,
Is it true that Reflectix shiny cell foam insulation can lead to overheating and seal failure on dual pane windows? If so, perhaps a small gap should be left at the top and bottom to allow for convection. This might even add a small amount of solar heating to the interior.
How about bubble wrap? Wet the window and stick it on. When we faced shortages on some of the usual insulation kits, we tried this at home on windows least exposed to the sun. Worked great!
If you’re trying to block sun, go mad with the Reflectix. If you’re trying to INSULATE, it’s next to worthless. Good quilted shades are probably better. Rigid foam insulation cut to fit is way better.
Air conducts heats much less than glass. A single pane glass window has a R-value less than 3 while a double pane window with a gas or air gap should have an R-value better than 3. Placing bubble wrap directly against the glass probably will not increase the R-value by much. Having plastic film well sealed to the inside window with an air gap might bring the R-value up to 6. Compare that to the R-value of block closed cell foam which is very good, far better than windows. In houses, Pella is among the best for window R-value as there is a large space between panes. In fact, they can be equipped with a slim shade, slats like a venetian blind that can be closed or open but not raised.