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RV Insulation: Keeping the Cold Out & the Heat In

RV Insulation: Keeping the Cold Out & the Heat In

As winter approaches, thoughts of keeping warm spring to mind (including RV insulation). That’s especially true for those of us who are full-timers and those who enjoy occasionally camping in late fall or winter in areas where temperatures drop significantly.

What’s the insulation like in most RVs? And how can we improve on our rig’s insulation during our travels in areas where it gets cold at night – or all day and night?

Today we’re looking at RV insulation – what it’s like from the factory and how we can make it better.

It’s getting cold, so let’s get to it!

What Are the Most Common Types of RV Insulation?

Most RVs have walls that are insulated with fiberglass or foam insulation (either rigid foam or spray foam).

The effectiveness of insulation is measured by the R-value, which is the term for the thermal resistance of any insulating material. The higher the R-value of the insulation, the greater the thermal resistance and thus the better insulated your RV walls (and ceiling and floors) are. The R-value of RV insulation varies greatly.

For example, foam board insulation is a type of insulating material found in some RVs and campers that may have an R-value as high as 20 or as low as 5.

There are motorhomes, travel trailers, and 5th wheels that are marketed as all-weather or 4-season RVs. These typically have insulation with R-values or R-1o or higher. The doors of these RVs (including insulated bay doors) often have different R-values than the side walls of the rigs.

In general, a well-insulated RV might have insulation with an R-value of 20 in the ceiling and 10 in the walls. This may sound very low to a sticks & bricks homeowner. But while those numbers may be low when compared to house insulation, it’s actually high where RVs are concerned.

But RV manufacturers tend to operate under the assumption that most RVers use their rigs in mild temperatures, so many RVs aren’t particularly well insulated.

Let’s take a quick look at the three most common types of RV insulation and the features of each, both pro and con.

Fiberglass RV Insulation

The most common type of RV insulation is fiberglass insulation, also known as glass wool. It generally has a relatively high R-value which is protective from both summer heat and winter’s cold air.

Fiberglass insulation is an affordable and effective way to maintain relatively consistent temperatures inside an RV over a wide variety of ambient conditions.

Fiberglass insulation is easy to install and usually easy to replace if necessary (if it’s accessible).

There are several advantages to fiberglass RV insulation:

  • High R-value
  • Low cost
  • Easy to install

Fiberglass RV insulation has a few disadvantages, however:

  • Easily damaged by moisture
  • Lack of moisture resistance can lead to mold
  • May need to be replaced more often due to the reasons just noted
2 Pack Owens Corning R-13 Pink Kraft Faced Fiberglass Insulation Roll 15 in. x 32 ft. (Packed by Eagle Electronics)
  • R-13 faced insulation, easy exterior/interior 2x4 wall install
  • Fiberglass insulation roll helps maintain temps and control noise

Rigid Foam RV Insulation

Rigid foam insulation is far more resistant to moisture and is more durable over time due to its construction.

Rigid foam insulation resists mold growth because it doesn’t collect moisture that can build up in an RV from showering, cooking, propane heat, breathing, and traveling in humid climates.

Foam insulation comes in a variety of densities/thicknesses with different R-values, and because the panels are rigid they offer a tighter seal for better insulation. (The R-value of rigid foam used in RVs is typically anywhere between 3.5 and 6.)

The benefits of rigid foam RV insulation are:

  • Durability/Lifespan
  • Available in multiple R-values
  • Resistant to moisture

There are a few disadvantages of rigid foam RV insulation including the following:

  • Cost
  • Can be more difficult to install
Owens Corning Pink Foam Insulation Board 2" Thick (8 Pieces-1.25sqft Each) Foamular Boards for Craft or Home Improvements Projects Such As Window, Wall, Ceiling Coverings. Packed by Eagle Electronics
  • This Insulation Is Moisture Resistant XPS Insulation Foam Board. It Does Not Crumble Into Small Pieces Like Styrofoam. Size of 1sqft per panel is...
  • 15" by 12" by 2" Insulation Pieces R-10. Great For Covering Small Places That Need More Insulation, Such As Walls, Around Windows,, On Floors, Attics...

Spray Foam RV Insulation

Spray foam RV insulation is a very lightweight alternative that’s relatively affordable and easy to apply.

This type of RV insulation comes in a can, allowing you to apply it in tight drafty areas to create an effective seal against outside temperatures as well as moisture.

Among the benefits of spray foam insulation are:

  • Provides a tight seal
  • Has superior moisture resistance
  • Extremely lightweight
  • Inexpensive
  • Can be more effective at blocking noise than other types

There are, however, a few disadvantages to spray foam insulation, including the following:

  • Must be applied accurately
  • Application can be tricky and messy
  • Has a lower R-value than both fiberglass and rigid foam insulation
Kraken Bond Fastcoat Spray Foam Insulation Kit- Insulation Foam Spray Polyurethane Spray Foam Heat Insulation&Acoustic Spray Self Expanding Foam Foam Insulation Can Gun/Cleaner Included | 6 Pack
  • EASY & STRONG BONDING: Kraken Bond Fastcoat Polyurethane Spray Foam is paintable and adheres excellently to most building materials. It comes with two...
  • QUICK CURING TIME: Thanks to Kraken Bond Fastcoat Polyurethane Spray Foam's strong chemical bonds, you no longer have to wait long. Note that bonding...

How Can I Improve the Insulation of My RV?

There are a number of things an RV owner can do to improve insulation, helping to keep the winter cold (and summer heat) from overwhelming a camping experience.

Let’s take a look at some of the easiest things you can do to improve the insulation of your RV.

Insulate RV Windows and Doors

Doors and windows are areas where cold can sneak in, but fortunately, there are many ways to address this issue.

Add Reflective RV Window Insulation

Reflective insulation blocks UV rays from the sun but it also helps to insulate windows and doors from the cold. It’s easy to use and generally sits nicely in window casings if you cut the pieces about 1/4-1/2 inch larger than the window itself.

It’s affordable, effective, and a very popular way to insulate windows. It can also be used to insulate air conditioning openings and other areas.

Reflectix BP24025 24-Inch by 25-Feet Bubble Pack Insulation, 1-Unit
  • Reflective insulation for use in a crawl space, attic, wall, metal buildings and post and frame structures
  • Fiber free, environmentally safe, easy to install and lightweight

Repair or Replace Caulking

Caulking around doors and windows can shrink or crack and fail to seal well after a while.

Check the caulk around your doors, windows, skylights, air conditioners, and vents for cracks, fraying, peeling, and loss of a good seal. Re-caulking as needed can go a long way toward keeping the cold (and heat) out of your RV.

For use around windows and doors:

Geocel GC28100 Pro Flex RV Flexible Sealant - Clear
  • Flash Point: 93.0 Degrees_Celsius
  • Excellent Adhesion To Many Surfaces, Even When Damp

For use around skylights:

SUREBOND BriRus SB140 Skylight Sealant (SB-140 T White)
  • Flexible butyl rubber sealant
  • For sealing rv skylights

For use around vent fans and other rooftop items:

Dicor 501LSW-1 HAPS-Free Self-Leveling Lap Sealant for horizontal surfaces - 10.3 Oz, White, Secure, Ideal for RV Roofing, Maintenance, Repair, Appliance Application
  • RV ROOFING USE: Lap sealant is sun-ray stabilized to avoid spoiling and discoloration; Plus, it will not stain or discolor any roofing material to...
  • COLOR: White hue for stylish and beautiful RV roof

Replace Worn or Damaged Weather Stripping

Any weather stripping around doors can become damaged or wear out over time.

Look closely at the weather stripping throughout your RV and replace any that isn’t up to the job. Sealing up those gaps will go a long way toward better insulating your RV against the cold.

This includes doors, windows, and even slide-outs.

Take care to note the type of weather stripping you need to replace. Here are some common options:

VITAM AMO Weather Stripping Seal Strip for Doors/Windows 18 Feet, Self-Adhesive Backing Seals Large Gap (from 5/16 inch to 15/32 inch), Easy Cut to Size
  • SEAL AND KEEP OUT UNWANTED WIND, WATER, LIGHT AND SOUND! - The simple use of the draught excluder around a door or window frame can drastically help...
  • EPDM MATERIAL! This sealing strip is made of VITAM AMO's specially formulated EPDM rubber, which has excellent performance in low temperature...
Foam Insulation Tape, Weather Stripping Seal Strip for Doors and Windows,Sliding Door,Soundproofing Door Seal,Weatherstrip,Air Conditioning Seal Strip (1/2In x 1/4In x 33Ft)
  • 【Foam Insulation Tape】— The foam tape is made from environmental protection material, CR foam, Neoprene, which has excellent sealing and...
  • 【High Density Foam Tape】— Provides a perfect air-tight seal, sound proof, heat insulation, weather proof, oil resistance, resistant to...
Black Rubber 018-312-EKD for 1" x 15/16" x 35' D-Seal RV Slide Out System
  • ☆The ultimate slide out seal system
  • ☆Easy installation, Contains UV inhibitors for longer life

Upgrade Doors and/or Windows

After a long time spent traveling along highways and bumpy terrain, there comes a time when some RV doors and windows may need to be replaced.

Single-pane windows in particular are very ineffective at blocking the cold (and heat).  Double-pane RV windows offer insulation that’s far superior to single-pane and may be worth considering, especially if you travel in areas of deep cold or high heat.

RV window replacement can be a DIY project, or you could opt for professional installation.

If you’re considering replacing one or more windows in your RV for any reason, check out our window replacement video to see if you think you’d like to tackle a similar project yourself:

Use a Door Snake

Putting a door snake at the bottom of any door where you feel a draft tends to be helpful. Door snakes are generally inexpensive and can even be self-crafted if you’re handy.

Measure the bottom of the door to make sure you get a snake that’ll cover the entire drafty area.

MAGZO Door Draft Stopper, 36 Inch Under Door Draft Blocker Noise Stopper, Weighted Wind Blocker Draft Guard for Bottom of Door, Gray
  • ALL SEASON PROTECTION - The durable sound proof bottom door weather stripping keeps your room warmer in winter and cooler in summer. The wind proof...
  • MULTI-FUNCTION DOOR SNAKE BLOCKER-The door snake blocker is dust proof, windproof, has good sound insulation effect, can stop the hot and cold air...

In addition to insulating doors and windows, there are a number of other ways to improve the insulation of your RV.

Check Sealants Around Storage Compartments

If the caulk or weather stripping around your storage compartments is worn out or damaged, replacing it will improve the insulation in those areas.

Use Vent and Skylight Insulators

Blocking the cold (or heat) from entering your RV through skylights and vents can really make a difference.

Skylight and vent insulators are affordable and very easy to insert into openings that will otherwise allow cold and heat to penetrate your RV.

Sizes are fairly standard, but be sure to measure the opening of the area you want to cover prior to choosing the insulator that’s right for your rig.

Camco Camper / RV Vent Insulator and Skylight Cover - Features 3 Layers to Reduce Heat Transfer & Increase A/C Efficiency - Fits Standard 14” Travel Trailer / RV Roof Vents (45192)
  • RV VENT REFLECTIVE INSULATION: Camco’s vent insulator blocks the sun's damaging rays. It helps keep your RV cooler in the summer and warmer in the...
  • SAVES ENERGY: This product reduces heat transfer and increases A/C efficiency.
Waterproof Non Slip RV Vent Insulator and Camper Shower Skylight Cover with Reflective Surface, Energy Savings, Fits 14"x22" RV Vents
  • Keeping the heat out of the rv with the reflective side, blocks out the sun, keep heat out or cold out, helps to save on your electric bill.
  • Full 2.8 inch of foam to help stop heat/light transfer.

Use RV Skirting if Stationary

If you’re living in your RV during the winter months in an area that gets very cold, RV skirting for winter could offer the underbelly of your rig some decent insulation. It can make a major difference!

Upgrade your RV’s Insulation

And finally, it may be necessary to upgrade the insulation behind your RV’s walls.

If you’ve got an older RV in particular, the insulation may have little R-value or may need to be replaced for other reasons. Or maybe it wasn’t built to be an all-season RV, but you’d like to modify it to allow more comfortable winter camping.

As noted earlier in this post, you can replace your fiberglass insulation, install rigid foam insulation panels, or use spray foam insulation to improve the insulation in your RV (as long as you can access the areas that need upgrading).

If you’re in conditions that require insulating your rig from the cold, you’ll almost certainly need to protect your water hose from freezing, too. We use the best one on the market — NoFreezeWaterHose. You can get a discount on one for your own rig with the link and discount code here:

NoFreezeWaterHose keeps your RV fresh water flowing in freezing temps!
NoFreezeWaterHose 5% Discount
Save 5% on your order at Use these high-quality, durable, made-in-America heated & insulated hoses for your fresh/sewer water lines... and rest assured both will stay...Show More
Save 5% on your order at Use these high-quality, durable, made-in-America heated & insulated hoses for your fresh/sewer water lines... and rest assured both will stay flowing down to -30℉! Show Less

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Saturday 12th of November 2022

What about wool insulation?


Monday 14th of November 2022

It's an interesting option, but in the tight spaces in RV walls, etc., it could be hard to get enough of it in place to provide sufficient insulating (compacting wool insulation reduces its insulating ability). But it could be good a good option in more open spots (like under the floor between chassis rails, etc).

Joey J

Friday 11th of November 2022

What about the floor, the floor of our 2022 Winnebago is the coldest area and crawling under the RV looking up, I do not see any insulation - no mention on how best to insulate the bottom of the coach


Monday 14th of November 2022

Hi Joey. Good question... that can be a tough spot to insulate. If you're parked for any length of time in cold weather, the best option may be to install RV skirting (check out this article: to help keep the cold wind from sucking heat out through the floor.

If that's not an option, you may need to find a way to attach some other insulation option (like Reflectix) in place wherever you can, to help stop the heat loss.


Friday 11th of November 2022

Good information. I would like to hear from people that have found a good way to insulate their storage bays. In particular the wet bay. While traveling last winter, the only thing I had freeze was the water pump. Didn't take much to thaw, but it was a pain. I already had heat tape on the pipes, but the pump still froze. Has anyone cut foam board to cover the door opening on the inside? Naturally it would need to be removable to have access to the inside.


Monday 14th of November 2022

Hi Howard. Insulating tight spaces like that can be a pain. If you're hooked up to shore power, running a 60-Watt incandescent light in the water bay can add just the right amount of heat to keep the temperature above freezing. We covered that in our 15 tips for winter RVing article.

Jimmy Edwards

Friday 11th of November 2022

Good information, good video. Very helpful. Thank you

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