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Tips for Winterizing RV Widows

More and more RVers are using their rigs year around which means taking some extra steps to keep the cold out and the warm in during cold weather.  Many RVs now have dual pane windows available as an option but even these could use a little help in the insulation department.

A single pane window is an enormous source of heat loss.  Insulating the windows not only helps keep it warmer in the rig, but also will help prolong the LP source as the furnace will not need to run as much.

Keep in mind there are many other places that are a source of heat loss such as the entrance door, refrigerator vents, and another huge area is the underside of the rig which should be sealed and skirted if stationary.  However in this article we are going to concentrate on the windows.

Tightened and Sealed

  1. The first step is to ensure your windows are properly tightened and sealed.  Some manufacturers use a putty-like tape called butyl tape between the window frame and the sidewall outside. Others simply use silicone. Whatever sealant is used, make sure it is intact and reseal if needed.
  2. Also check how the window is mounted. Most use a sandwich design with the window and flange on the outside and a fastening ring on the inside connected with screws.
  3. Make sure the screws are tight so the entire window provides a good seal.

Adding Insulation

When adding additional insulation or products to the window, you are trying to increase the R-Factor or Resistance to Heat Flow. Here are some products being used by RVers:

  • Dual Pane Windows

    • Some cold weather RVers will actually replace the original single pane windows with dual pane replacements. This can be very expensive.  Keep in mind, dual pane windows in an RV are simply two panes of glass with air inside, not argon filled like the low-E type you would find in a home. So these typically still need some additional insulation in cold weather. You can get replacement dual pane windows from any RV parts supplier, or Lippert Components Inc (LCI).Double Pane
  • Reflectix

    • The Reflectix double reflective insulation is a great product as it’s easy to work with, cut, and apply. The product features two 96% reflective layers of film bonded to two layers of polyethylene bubbles and can be cut to the exact size of the window. Most RVers cut the finished product slightly larger than the window to cover the frame as well.  They then either tape around the edges, or use a double sided tape to seal it. This provides three times the restriction of heat flow as the single pane window.
    • The downside are that it does block the window so you don’t get any light inside, heat, or cannot see through the window. Also, you cannot open the window if the temperatures do get warm enough to let in some fresh air.

Reflectix Small Project Rolls

Cutting Reflectix Small Project Rolls

  • Plexiglass 

    • Plexiglass comes in a variety of thicknesses and can be cut to the desired size of window and installed over the existing window to provide a type of dual pane. Once again, this is only providing an air space inside, but will provide additional resistance to heat flow. Some RVers use Velcro to attach it, however this does not provide an air tight seal and is not as effective as using two sided tape or double sided foam seal tape which you can find at any home improvement store. Popular brands are Gorilla Double Sided Mounting Tape, Duck Permanent Foam Mounting Tape, or Scotch Double Coated Permanent Mounting Tape.
    • The downside of this type of insulation is the window cannot be opened, and the tape needs to be removed and reapplied each year if the window is to be used for normal operation during good weather. To make it easier to install and remove a Plexiglas cover, you can use single sided mounting foam on the cover and plastic mirror mounting clips.

Screws and Plastic Mirror Mounting Clips.


  • Shrink Film Kits

    • One of the most popular window insulation products is the shrink film kits available at any home improvement store. They are easy to install and remove in the spring and inexpensive as well. There are a variety of brands such as Duck, 3M, M-D Building Products, and Ace Hardware. These are easy to install.  Simply, apply the two sided tape around the perimeter of the window, peel off the second side of the tape, and apply the plastic sheet. You can get pre-cut sizes. However, I have found these to be sized for residential windows and not what is in my RV so measure your windows and see what kit works best with the least amount of waste.
    • Apply the film and use a blow dryer to shrink it down to a nice tight, clear cover! You might find it difficult for the tape to stick, especially if you apply it to the metal frame of the window. This could be due to a weak or old tape, cold metal frame, or moisture? You might need to apply it outside the frame to the wallboard. There have been times I needed to purchase a stronger tape that would stick to the surface and stay for the winter! I would also recommend getting the thickest film possible which will be listed as MIL.
    • The only downside of this application is you cannot open the window, plus if you have pets, they can really have a fun time shredding the film! Also it’s an ongoing project each year.



Since the Reflectix provides the best insulation or R Factor, it’s a great product to use in windows that you don’t need to see out or have sun coming in such as a bathroom, bedroom, or hallway. Then you can use either the Plexiglas or shrink option in other windows to customize your rig for cold weather enjoyment!

About the author: Dave Solberg: Managing Editor, RV Repair Club

For the last 25 years, Dave has conducted RV maintenance and safety seminars, developed dealer and owner training programs, written RV safety and handyman articles, authored an RV handbook reference guide and logged over 100,000 miles on the road in an RV.

RV Repair ClubRV Repair Club is your go-to online resource for enthusiasts who want quality RV maintenance, repair, and upgrade information – a community where passionate RVers can come together to gather knowledge and share their experiences.

Learn more about RV Repair Club.


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