Using an RV in Winter (below 0°F)

Very few people run their RVs through real winters with water in the pipes. Our local emergency preparedness people boxed in all the pipes and tanks on a Class A, have two independent furnaces, a loud external alarm that goes off if the temperature inside goes below 50°F, and a heated garage for it. Notes from some others are below - as soon as they run out of propane unexpectedly, or have a furnace fail-to-start, and get the repair bill, I bet they join the rest of us!

I run all through winter in Ottawa (Canada) with an 17' Class C - it usually gets colder than -20°F each winter.

It works, so it's one way of doing things. No computer problems either (PC with solid state monitor, modem, 50' telephone extension cord). The only problem I had was that the blackwater tank was originally slung under the frame - the drain valve stuck down too low and got broken off when driving through a snowdrift the first year. I replaced the underslung tank with a smaller one tucked up out of harm's way, and it works fine now.

Propylene glycol goes solid when mixed with what goes into a black water tank, but it doesn't burst things the way pure water does. You will have to wait for a warm day (above 10°F) to dump unless you use an external heater. ABS drain piping seems to fail long before tanks do - if your dump valve is mounted directly on the tank, that seems to be best. John Sankey

You will find RV's in the parking lots in quite a few ski resorts. It just means a few sacrifices. When you pull up turn your furnace on, and don't use your water system for much. You can put RV antifreeze in your potty and use it if you choose, but most just add the antifreeze and don't use the water at all. For drinking water keep your water in 5 gal water jugs near the furnace. When you put something down the drain keep the grey water outlet open and place a 5 gal pail below it, drain the pail very often. Use the hottub and shower in the chalet for your personal needs. It might sound crazy but it is done! (

I have an Edson Nordic 23' class C, quite old now and they are no longer in business, but there are still a fair number around. It has boxed in tanks, a hot air pipe from the 31,500 BTU/hr furnace is fed into the box which keeps every thing warm. It also has a set of storm windows held on by mirror clips that take an hour to put in the fall, and a leather blanket that snaps on to close off the cab area when parked so it lessens the heat loss out through the cab area.. We have skied in Banff and Jasper at any time in the winter with no problem and use it as though it was summer. I antifreeze it each time we come home and take on water each time we go out. (

I used my trailer all winter long for 5 years. In that time I had a travel trailer and a fifth wheel. I used it down to -26°F. My tanks were not in warm compartments so I had to put antifreeze in them. I did use the shower stall, but I warmed water up on the stove and poured it over myself with a glass. After I was done, I put just as much antifreeze in the tank as water I used. I lived in my trailer three days a week. I had two 30 lb. propane tanks. I could go about 5 weeks on those two tanks. It depends on how warm you need it. If you are just using the trailer for sleeping, you can get by with using electric blankets. Some nights, even though it was really cold, the blanket really was all I needed. (

I've been winter camping now in Ontario Canada for 7 years. I leave my grey and black water tanks open at all times, wrap my water hose with electric wrapping tape/cord and plug in at all times, and shield my outside propane regulator from freezing winds. A 1500 watt electric heater will save on propane and wear and tear of furnace, and an electric blanket is highly recommended. Experience is the best teacher. If you look upon it as an adventure, winter get-away can be a lot of fun. (

During cold weather, water vapour will collect and freeze on the cold metal skin directly above your overhead lights where the insulation has been cut away at the factory. When you turn on the lights, the heat generated melts this condensation. Pull off every overhead fixture and stuff the hole in the ceiling panel with insulation. Make a box 18" X 18" X 12" high to place over every roof vent. Drill three 1" holes in both sides of the box to allow for air circulation. Leave your roof vents open about 1" at all times to vent excess moisture. The box helps to keep cold air from cascading down through the vent. Unless you want to view Jack Frost's creations in all their drippy splendour, you should instal storm windows of some sort. Ours are sheets of plexiglass cut to fit each window that instal on the inside with plastic L-brackets every foot or so. Foam tape supplies a seal to the window frame. Plastic storm windows that you heat shrink into place work well, too, although the tape used can be messy to remove. Most RV doors have little or no insulation in them and are a prime heat loss area. Also the aluminum frame conducts the cold into the unit whereupon the moist inside air condenses to form frosty strips down the wall. Our solution is a door blanket, made of a nylon quilted material similar to a sleeping bag, that snaps on over the opening at night. Through necessity (and just to generally make life miserable) inside plumbing pipes are routed through the most inaccessible parts of the RV and that is exactly where they will freeze first. Insulating foam tubes are fairly inexpensive and will help here. (

For 9 years I full-time RV'd at construction sites in the western USA and Canada in a 35' 5th wheel. Until they were of age to start school I took along my family starting with 5 of us and finishing with 7.

I used a rubber 3" car heater blower hose for my sewer drain connection. It can be had at any auto parts store. The last one I bought was in 1983, it still does not leak and it coils up small. I have used it in -42°F in Fort McMurry Alberta and to 121°F in Overton Nevada. I had a 6' length for dumping stations and a 15' length for when connected, which I supported with two different lengths of plastic rain gutters, making it adjustable. In real cold, I added more gutter pieces turned over, to keep the heat from a heat tape in the sewer hose area. I left the grey tank open (down to -40°F once) so I could leave a tap dripping. Don't use the heat tapes that have a sensor on the end, just the kind that only heats up on the portion that is at or below freezing. It is the only kind that can be crossed over itself.

For dumping when there was not a sewer connection at the job site, I used a bladder tank that rolls up when not in use. I have one I bought in southern Alberta in 1980, not sure if it is rubber or vinyl. It is 150 gal., has a 3" connection at one end and hose type connection on the other end, with valves. I unroll it in the back of my truck, then use a short piece of rubber 3' hose to connect the RV to a 12V macerator pump. The pump chops it up and puts the grey/black water in a smaller hose to empty both tanks. The smaller hose black/grey fluid will go down a garden type hose to a near by toilet or other type drain, I have gone as far as 250' with hoses (only used for that). If no sewer is available it lifts it to my bladder tank. Most times I can empty my RV 2-3 times before having to take it for dumping. I use a different 100 gal. bladder bag to bring back potable water. I only use white hoses for potable and black hoses for grey/black water to avoid errors.

I ran awning rail track around the lower part of my RV and up around the hitch area. Then I bought truck tarping, it came in 6' wide bolts. For around the hitch I left it full length, for the rest I cut it in 3' wide pieces. I sewed a small rope in the top edge, which allowed me to hang it from the awning track, and a flap sewed all along the lower edge of the tarp to insert a plastic 1/2" pipe. They were made of the lengths that could be stored easily and fit together with elbows at the corners. I would start hanging it at a wheel well and go out in both directions from there. There was a little flap sewed in to cover the wheel wells. It worked far better that the thin vinyl ones they sell and cost less. It made a huge difference in the floor temp of the RV.

Around my fresh water supply hose I used foam insulation large enough to put heat tape in it. Make sure it is the type you can use on plastic pipe. If it did freeze I used a hot air gun to thaw it.

I had two 40,000 BTU Hydroflame furnaces. All my fluid tanks were located above the frame under the bathroom area, with one heat hose from each furnace heating the tank area, so all valves and connection were in a heated area. I had two 40 lb propane tanks on the 5th wheel and a 100 lb tank hooked up as well. That would last a week in -40°F weather. (

Get Bob Livingston's book "RV Repair and Maintenance" if you don't already have it - it's full of all sorts of things you should know about your RV. The most important thing prior to winter is to get all the water out and instal RV antifreeze in all of the vulnerable areas. The most vulnerable parts are the water pump and the plastic valve in the toilet - if frost damages the toilet valve the only repair usually available is a fairly expensive overhaul kit for the whole toilet. Some owners use compressed air to blow the lines out, but you will lose your pump at 30 below if even a trace of water remains in it. The following RV antifreeze method is much safer.

(thanks to


In winter, we really rely on batteries, to crank engines stiff from cold and to run a furnace. At 0°F, the usable capacity of a lead-acid battery is about half its rated (70°F) capacity. And, its voltage is almost a volt higher than in summertime, so your vehicle alternator may not fully charge it. The only safe way to determine the state of charge of a battery at these temperatures is with a battery hydrometer. Judging battery charge with a voltmeter is too inaccurate.

Battery hydrometers are usually marked with a colour-coded scale. This colour scale applies to your starting battery - for your deep-cycle coach battery, use the following:

charge  specific gravity
 100%      1.260
  75%      1.225
  50%      1.190
  25%      1.155
   0%      1.120 

So, if your battery is rated for 220 AH at 70°F, and a hydrometer reads 1.19 and 0°F, then you have 50% of 110 AH or about 55 AH available. Don't guess - measure the current your furnace needs to run. On a cold night, measure what percentage of the time your furnace runs, then make up a table showing the amp-hours you need per day vs. outside temperature. Fresh morning coffee is much more satisfying in a warm rig!


The last thing you need in the depth of winter is to suddenly find you can't get your propane tank filled. Here are the regulations that are followed by filling stations in the USA and Canada. Check them out in the summer, when you don't need propane for your furnace.

In the USA, the National Fire Protection Association code is generally used, although any state may impose additional conditions on anything forming part of a motor vehicle. The NFPA code requires that any container showing serious denting, bulging, gouging or excessive corrosion be removed from service. Tanks must be marked in accordance with DOT, ASME or API-ASME codes. If marked with either of the ASME codes, requalification is required only if involved in a fire. If marked with a DOT code, it is good for 12 years from the date of the manufacturer's mark. A DOT container may be requalified for 12 years if fully hydrostatically tested (tank expansion measured), for 7 years with a simple hydrostatic test to twice working pressure, or for 5 years with a "carefully made and duly recorded visual examination by a competent person". The visual inspection can cost as little as $4 - it's the way to go.

In Canada, regulation is split between a number of squabbling jurisdictions - there are at least eight overlapping approval agencies. Effectively, enforcement takes place when tanks are filled. Propane tanks may be visually inspected in accordance with the Compressed Gas Assoc.Inc. Pamphlet C-6, but most suppliers require that portable cylinders be requalified by a test to 300 psi every 10 years in accordance with the federal Boiler and Pressure Vessels Act - typical cost $50. Tanks used to power a motor vehicle must be visually inspected to provincial criteria every 5 years in most provinces. But, ASME-type tanks used solely to power RV appliances seem to have no effective inspection requirement - it's up to each supplier each time the tank is filled.

In both Canada and the USA, regulations prohibit filling a propane tank more than 80%, and require that the tank be purged if overfilling happens by accident. Winter RV users have a special reason to take an interest in this. Propane stays liquid only at high pressure, 100 psi or so, and is reduced to a standard pressure of 1/3 psi (11" of water) by a regulator on the tank. If your tank is overfilled, liquid propane can get past the tank regulator into the lines, and instantly you have 100 psi on your furnace. That usually cracks the furnace regulator diaphragm, because all seem to be designed for a maximum of ½ psi! And, most regulators cost $100 or more to replace. So, close your main tank valve while your propane tank is being filled, require that the filler verify then and there that your tank is not overfilled, and insist on immediate corrective action if it is. If you are a furnace manufacturer who uses a regulator that is not designed to self-destruct every time overfilling occurs, please contact me, and I will gladly publicize your product here.


In mild climates, it is possible to take the chill off an RV with a catalytic heater. These require no circulating fan, some require no electricity at all. But, they dump their combustion products, water vapour and carbon dioxide, into the living space. So, they require ventilation to prevent you suffocating with carbon dioxide, and to prevent everything turning to mildew with moisture - too much ventilation for real winters.

Below 0°F, a furnace must be vented to the outside. Old units did this with convection, but all new units I am aware of do it with 12V power - lots of it. And, they all now seem to have a very dangerous feature - if the propane runs low, they leave the fan running nonstop until your coach battery is discharged totally, freezes, cracks, then dumps sulphuric acid over everything around it. Again, if you are a furnace manufacturer and your units shut down properly when ignition fails, I will gladly publicize your product. I note that this offer has been outstanding now for 3 decades, and that neither of the remaining RV furnace manufacturers, Hydraflame or Suburban, has accepted. Why hasn't someone living in the USA sued them? This a basic safety issue. After all, Dinosaur makes a board that behaves properly, and all you have to do to live safely is to void your furnace warranty and replace your Hydraflame or Suburban control board.

How much heat do you need? Answer 3 questions: how cold? how well insulated? how big?

  1. How cold does it get outside and how warm do you want it inside? Start with a temperature difference of 80F (60°F inside, -20°F outside) in southern Canada.
  2. How well is your RV insulated? If it is not specially winterized, and you have single pane windows, start with a guess of R3. Guess R6 with a "winterized" RV with double windows. Do not use the "R20" or some such marvellous figure supplied by a manufacturer - wood studs are R3, double windows are only R2, and doors are usually even less.
  3. How big is your rig? The wall area through which heat flows is
    (length x 2 x (width + height)) + (width x height x2)
    For my 17' class C, with an insulating curtain between the cab and living space, I get 600 sq.ft.

Then, multiply the temperature difference you need by the wall area and divide by the R value - 80x600/6 for my rig - 8000 BTU/hr. That is the minimum output required of a furnace to keep things warm. If you want to save on propane by letting it cool off when you are not in it, but turn the heat up on your return, or you go in and out at all often, you should add 50% to this capacity if reheating is not to take many hours.

How big must the furnace be? Furnaces are rated by the theoretical heat of the input propane, not the heat output, and few RV furnaces are more than 60% efficient. So, my rig needs a furnace rated at 8000/.60 = 13000 BTU/hr for light-sweater living at -20°F outside. As a reality check: I have a 20,000 BTU/hr Suburban furnace. I got stuck one winter in Norwood Ontario at 35 below and 50 mph wind. It held inside at 50°F.

How much propane do you need? Propane's heat content is about 22,000 BTU/lb. So, for a no-sun day at -20°F, my rig needs 13000 BTU/hr for 24 hours. 13000x24/22000 = 14 lb (16 l) propane. Remember that a "20lb" tank can only hold 16lb (80% full). If you travel in winter, you should always keep a couple of days of heat in reserve for a bad storm.

How much coach battery capacity do you need for the furnace? Furnaces vary greatly in their power requirements - mine uses 2A, so I need 48 A-hr per day at -20°F, and can count on my 220 AH golf cart set only for 3 days. (That's why I miss my old Coleman unit, that used less than 1A, and that only while propane was producing heat, until a careless propane station overfilled my tank and destroyed its no-longer-made regulator.)

Rust and Corrosion

In areas where it gets cold, most road authorities use salt mixtures to help keep roads clear. Salt plus steel equals rust; salt plus aluminum equals pitting.

The most effective protection for steel against salt-induced rusting is oil that stays sufficiently fluid that it flows over damaged areas to keep them protected. You should go once a year to a firm specialising in this for best results - they add active rust inhibitors and have effective procedures to contain their materials around their premises. (In Canada I recommend Krown Body Maintenance.) If you do it yourself, note that used oil is not as good as new - oil becomes acid after use in an engine.

Aluminum is much more difficult to protect against salt corrosion, in fact salt is prohibited on airports for this reason. (Airports use urea, over 10x the cost of rock salt, and sweepers to keep runways clear.) If you run through winter, you just have replace the lowest panels of your rig every 5 years if you want them to look smart, in my experience. I do not recommend the coatings sold under the trademark Storm King to "protect against salt corrosion". They look absolutely filthy within months and can not be cleaned even in a truck pressure wash - road dirt goes right into the coating itself.

John Sankey

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