RVs in Sub-Freezing Weather

Full-time RV living can sometimes push you and your rig into climates that aren’t as friendly for full-time (or even for a casual weekender). Most RVs of all types are designed for three season use. The insulation isn’t typically amazing by residential housing standards. That doesn’t mean you can find four season coaches, many exist and can keep you fairly cosey inside. Alas, not all coaches are set up for super cold weather, so knowing how to keep your RV safe in sub-freezing temperatures is critical.

Interior prep

Preparing the inside of your RV for cold weather is a bit easier than the outside. It is somewhat similar to a residential prep. You can do a lot to prevent heat loss and we’ll cover what we did in ours during single digit temps, and we’ll list some additional things you can do on the inside.

Filling the “holes” in your roof

RV Vent Insulator

RV Vent Insulator (click for link)

One of the first things we did, was to buy inserts for our fan vents. They are foam blocks with most of it being a soft faux lambs wool on all sides but one, which has Reflectix. Reflectix is basically a Mylar bubble wrap that is really effective at reflecting heat, both inward and outward. They insert into the fan vents Reflectix side up and boom the holes in your roof now have insulation.

The other bonus of these insulators is that they work in summer a well, to keep the heat out. So you get all year usage out of it.

Stopping drafts along the slides

Slides are a major component of nearly all RVs these days. They expand the living space significantly, but not all slides are created equal. Some slides are flush with the floor, this means they slide out and then down (usually a ramp system). These don’t require a lot of prep for cold weather, provided they seal to the floor well. Other slides are “step up” slides, meaning they slide straight out and stay level, leaving a ledge. Here is where we can add some help to keep drafts out.

In our case, we did two things. Firstly, we took a horse blanket and rolled it up and laid it along the edge of the ledge. This is old school, like I remember doing along doors as a kid. We did that in our one living room slide that has a ledge. This made a HUGE difference.

MAGZO Door Draft Stopper

MAGZO Door Draft Stopper
(click for link)

For the bedroom slide, we purchased some door draft stoppers. These lay in front of the slide in the same way as a rolled blanket would. The advantage of these is they can velcro together on the ends to create long stretches for longer slides.

Again, they are a foam product, but the fabric on one side is rougher, so it won’t slide as much, gripping the carpet. This did an amazing job, so that when we walked around in the bedroom, we didn’t get a cold draft on bare feet.

Window treatments

Windows are a huge source of heat loss in any living space. Our rig has dual pane windows, which helps immensely in keeping the cold out. But that alone isn’t enough. Most RVs come with box valances with shades. We yanked those out in one of our first remodels and replaced them with temperature control shears and linen curtains.

Shears and curtains
Sheers and curtains

There is a definite difference with the temp control shears. Again, these work both in winter and summer temperatures, which is nice for those days when you have bitter cold or direct sunshine. RVs in the summer are tin cans and heat up really fast. Sadly, that doesn’t happen in winter!

Another great thing we have for the times when the RV is facing the sun, is our windshield sun shades. They have silver on one side and black on the other. We can put the black side facing out if we want to absorb that free infrared the sun so nicely provides.

Other options

Other additions to temperature control in cold weather can be numerous and creative. Some of what we’ve seen other RVers do:

  • Reflectix on every window – this makes it very dark inside, but will add the benefit of reflecting any heat generated back into the RV
  • Blankets on windows – another old school remedy that will also make it dark, but add a bit of barrier to heat transfer
  • Cover windows with plastic – you’ve all see the shrink wrap plastic kits for residential windows, they work in RVs too
  • Area rugs on the floor – adding additional rugs on the floor add a nice comfy feel and keep some heat in

Exterior Prep

There is a lot to think about with the exterior of your RV in winter weather. Your RV sits on its tires, which is much like having a house on stilts. This means there isn’t any air underneath or foundations on the sides to help keep the heat in. This is a challenge because in many RVs, your water system is exposed on the underbelly. If untreated this can lead to frozen pipes, frozen water, or worse, frozen waste tanks. Trust me, you do NOT want a frozen black tank! Some folks we’ve seen who full time had their waste hoses freeze and burst because they attempted the trickling water technique in sub-zero temperatures.

Heat the water bay

Our RV has an enclosed water bay. This is nice because it keeps out the worst of the elements in inclement weather, but also on travel days. Our waste water valves and water intake are completely secure. Even so, the bottom is only a single layer of 1/4″ plastic, not a lot to keep heat in. We are fortunate that our rig has a system heat option, which heats our tanks and turns on a small ceramic heater in the water bay. This though, is a single point of failure.

Incandescent work light
Incandescent work light
(click for link)

For added heat in the bay, we went low tech with a recommendation from the RV Geeks, we added an automotive work light. A single 60 watt bulb will do wonders for adding a bit of heat in the bay without relying on other heating methods.

For example, some bays only have heat strips or heat blankets on the tanks, but nothing for the water connection or sewer valves. This simple approach allows us to take the edge off the cold with ease. Plus, we get the availability of a work light when we need won. RV living is about multi-use items as much as can be accomplished.

Keep your water source heated

With extended cold spells, keeping your water sources from freezing is critical. Most parks warn of water use during hard freezes. It can be costly and messy if a water connection freezes and not all parks insulate their water spigots. For us, while in the cold snap in Indy, we were fortunate that their water connections were below grade with pink insulation and covers. Still, that is only the first part of preventing a frozen mess.

Pirit headed RV hose
Pirit heated RV hose
(click for link)

Our solution was to buy a heated hose. This was a great purchase and kept our water hose heated during the cold. It has an embedded heat strip inside the durable hose that plugs into a 120V outlet. As you can see in the picture, the orange thermostat has a sensor that detects the temperature and automatically turns on when it gets down to about 40 degrees. We used a temperature gauge on it when it was 15 degrees outside one day and the side where the strip is was a balmy 56 degrees and the other side was at 30. It was warm enough to melt the snow when the white stuff kept coming down.

There are many brands out there, we chose this one based upon good reviews and for its durability. One note though, it is a bit bigger around than your standard hose, so, the deck plate for water could handle the diameter. We stuff steel wool around it to keep the hole closed and vermin out (another great trick from the RV Geeks).

Enclose your undercarriage

Wind and air are useful in summer months to cool the underside of your RV, air circulation can help a lot in the hot months. That is no benefit though in the cold in harsh winters. Our solution was to create a skirt of Reflectix. This allowed us to create a wind and cold barrier for the undercarriage all the way around in a pretty easy way. It wasn’t perfect, but we absolutely felt a big difference in retaining heat. Especially in the bedroom area, which is over the engine compartment that is completely open to the elements with only an inch of reflective insulation.

Our rig also has a side radiator, so we covered it up as well. We used a combination of 16″ and 48″ reflectix to surround the whole rig.

Plan for your heat sources

We knew we were going to be parked for 6 weeks and the cold was really setting in for 4 of those. So we had to look at our heating very carefully. Our rig has heat pumps, but those only work down to about 40 degrees efficiently. We also have 2 propane furnaces, but only an 80 gallon propane tank.

Firstly, we decided to buy a space heater with a thermostat. We set this up in the bedroom so that we could have it keep that space warmer overnight without having to run the rear furnace. This made for quite a bit of savings in propane. The downside is that the draw on the AC circuit was pretty large and it tripped our ground fault pretty hard. It was a pretty big draw and took some diagnosis to figure out it wasn’t the GFRC receptacle. Ultimately, we discovered that the circuit breaker on our inverter had popped. One thing to note, some parks specifically forbid the use of electric heaters. Their grids just aren’t beefy enough to handle that much draw, so, don’t expect you can use your electric heaters, you may only have propane as an option.

Secondly, we opted to order up an external propane tank. We had planned to install a tee connector inline on our propane tank to hook one up, but found that one had already been installed! So, we rented a 250 gallon external tank and we used about 2/3 of it over the course of our stay. It allowed us to avoid the need to pack up the rig and drive out to get a propane fill. While totally doable, it is a huge inconvenience and we might have had to do it twice. The cats appreciated not having to go through that.

Other things you can do

There are any number of options available for winter proofing your RV for a cold stay. Most are variants of what we did:

  • Build your own heated water hose – some folks buy a heat strip and tape it to their water hose, then wrap it in foam insulation tubes
  • Wrap your rig in foam insulation boards – we saw a lot of this for the long term RVers at the park we stayed at, from 1/4 to 2 inch foam boards, offering a higher amount of R factor for their undercarriage
  • Insert foam board insulation under your slide out floors – this keeps you much warmer since your slide outs are not as insulated
  • Use available snow – a trick from Gone with the Wynns is to shovel available snow up against your rig, creating a natural skirt to keep out the wind and really cold air
  • Use heat lamps – we saw some folks wrap the undercarriage and then use infrared heat lamps near their exposed valves
  • Reflectix on the outside of windows – applying another layer on the outside to provide even more insulation

You can RV in really cold weather

So there you have it. We survived super cold weather with relative ease. No frozen pipes, no fuel issues, and no worries (for the most part).

The takeaway is, if you plan accordingly, cold weather is completely doable in an RV. It just needs more planning. RV manufacturers have taken note and started doing more to allow for all year usage. They are putting equivalents of R40 in floors, R30 in roofs and R10 in walls on newer RVs, as well as ducting the furnace into the underbelly around tanks and valves. All this benefits you in summer as well, to keep the heat out.

But if your rig is older or doesn’t have a whole lot of insulation, you can still winter or survive a cold snap with some forethought. All of us who RV watch the weather constantly, so we usually have advance notice of bad weather. A little bit of creative thinking will certainly make a huge difference for your comfort and the care of your rig.

Happy camping!

4 thoughts on “RVs in Sub-Freezing Weather

  1. Dear Julie,


    This will be so useful if I ever go absolutely barking mad and take up RVing in the dead of winter.

    Or any other time of the year.

    Best wishes for an early Spring, and a speedy recovery,

    Uncle Allen

    PS If your rigamarole doesn’t already have a name (well, one that doesn’t involve cursing), may I suggest “Irving”?

    Get it? RVing = Irving. Besides, it’s a family name.

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