Winter Camping in an RV or Van: Plumbing, Batteries, and Heater Safety

Cold breaks things in a predictable order, and it is not the order most people expect. Your battery’s ability to accept a charge goes first, often before the air temperature reaches freezing. Your water lines go next. The heater you install to solve both problems is the only part of the system that can kill you, and the federal death numbers say it does so mostly in exactly the four months you would be using it.

Here is the systems view of cold, with the numbers we could verify and honest blanks where we could not.

The heater is the part that can actually hurt you

Carbon monoxide is colorless, odorless, and tasteless, and OSHA’s fact sheet is blunt about the consequence: large amounts of CO can overcome you in minutes without warning, causing you to lose consciousness and suffocate. It comes from incomplete combustion of anything carbon-based, and OSHA’s list covers what campers actually burn: natural gas, gasoline, kerosene, oil, propane, coal, and wood.

The scale is documented. CPSC staff estimated 211 unintentional, non-fire CO poisoning deaths associated with consumer products in 2020. Engine-driven tools, which is mostly generators, were associated with about half of that total (101 deaths, 48 percent), and 92 of those involved generators specifically. Heating systems were the second largest category at an estimated 62 deaths, 29 percent. Across 2018 to 2020, more than half of all the deaths (56 percent) fell in November, December, January, and February.

Two details from that report matter directly to anyone sleeping in a vehicle. First, CPSC’s “home” location category explicitly includes a non-fixed location domicile used as a home, giving camper trailers as the example, along with tents and temporary shelters. This is not purely a house problem. Second, CPSC notes that gasoline engine exhaust may not produce the irritating smoke that a wood or kerosene fire does, so there is no sensory warning at all before the gas reaches a dangerous level.

The practical rules follow from that:

• Run generators outside only. The National Weather Service’s extreme cold guidance says at least 20 feet away from doors, windows, and garages. A generator under an awning or in an open van doorway is inside as far as the exhaust is concerned.
• Use a heater designed to vent combustion products outside the living space, installed the way its manual says. An unvented portable heater burning fuel in a sealed sleeping space is the configuration behind the winter spike in the data.
• Fit a CO alarm and keep a working battery in it. Nothing else in the vehicle detects this.
• Symptoms mimic the flu. CPSC’s report notes that CO symptoms can be mistaken for influenza or a cold, both by victims and by physicians. If everyone in the vehicle has a headache and feels nauseous on a cold morning, get outside and open it up before you diagnose anything else.

That is the whole of the fear-mongering we are going to do here. It is a known hazard with a known fix, and the fix is cheap.

Your battery quits before your plumbing does

The threshold is warmer than you think, and it is a property of your specific battery, not of lithium in general. Victron’s datasheet for its 12.8 and 25.6 volt LiFePO4 Smart batteries lists the operating temperature as minus 20 to plus 50 degrees C for discharge, but plus 5 to plus 50 degrees C for charge. Plus 5 degrees C is 41 degrees F. That is a normal fall morning in the mountains, not a cold snap.

Read that carefully, because it explains a failure people misdiagnose as a broken solar controller. The battery will happily run your fridge and lights all night at well below freezing. It just refuses the charge when the sun comes up and the cells are still cold. Many batteries enforce this with an internal low-temperature cutoff, which protects the cells and leaves you with a bank that drains a little more every day.

We are not going to publish a single number for “lithium” because the spec varies by manufacturer and by whether the pack has internal heating. Pull up your own battery’s datasheet and find its charge temperature range. If you plan to camp where mornings sit below that number, you need a heated bank, a way to warm the battery compartment before charging, or a different plan. Our lithium versus AGM comparison covers the tradeoff, and if you are sizing a bank for shorter winter days, start with battery sizing.

Winter also shortens the solar day at both ends: fewer daylight hours, a lower sun angle, and snow on the panels producing nothing at all until you clear it. Whatever your summer power budget was, it does not carry over.

What freezes, and roughly in what order

Exposed and uninsulated runs freeze first. The city water hose left connected overnight, the outside shower, the low point drains, the pump, and anything routed through an unheated bay. Tanks last longer than the lines feeding them, simply because there is more water in them and water gives up heat slowly.

We are not going to give you an hours-to-freeze figure. It depends on wind, on how much insulation the manufacturer actually put in that bay, on how full the tank is, on whether the furnace ducts into the underbelly, and on how long you run heat overnight. Any number we made up would read like a fact and be wrong for your rig. What you can do instead is disconnect and drain the hose every night, keep tanks either fairly full or properly drained rather than a quarter full, and find out from your own manual whether your underbelly is heated.

The failure mode that costs real money is a split line or a cracked fitting, discovered in spring when you pressurize the system and water appears somewhere it should not. That is a repair, not a trip-ender, but it is an avoidable one.

Your propane does less work than the gauge suggests

A cold tank does not simply hold cold propane. It vaporizes more slowly, which is a delivery problem rather than a fuel problem, and it catches people who checked the gauge and assumed they were fine.

Emerson’s Fisher Regulators bulletin LP-27 gives the governing relationship. A tank’s vaporization capacity depends on its wetted surface area, meaning the portion of the tank actually in contact with liquid, because that is the only part transferring significant heat into the fuel. It also depends on the gap between the outside air temperature and the temperature of the liquid inside.

Two things follow for anyone running a furnace in real cold. A fuller tank vaporizes better than an emptier one, because as the liquid level falls the wetted area falls with it, and so does the rate at which the tank can deliver gas. And frost makes it worse rather than being merely a symptom: the bulletin describes frost forming on the tank wall up to the liquid level when gas is drawn faster than it can boil off, at which point that frost layer insulates the tank and restricts heat transfer from the surrounding air. The system fails when vapor pressure falls below what the regulator needs.

So a tank that is not empty can still fail to keep up with a furnace running continuously. Start a cold trip with more propane than the arithmetic calls for, and refill or swap before you are low rather than after.

One scoping note: LP-27 is written for stationary LP-gas installations, not RV cylinders. The physics of wetted area and frost carries over directly. The tank sizes and the numbers attached to them do not, so we are not going to convert its figures into a cylinder recommendation.

Condensation is the slow version of the heater problem

Sealing the rig up tight is the instinct in cold, and it creates a second problem behind the first. People produce water vapor just by breathing, and any unvented combustion produces more. In a cold vehicle that vapor condenses on the coldest surfaces it can find: windows, metal window frames, the wall behind the mattress, the underside of an uninsulated roof.

Wet insulation stops insulating, so the rig gets colder, so the instinct is to seal it tighter still. The mold turns up weeks later on a wall you cannot see.

Ventilation is the fix, which feels exactly wrong when you are trying to stay warm and is not optional. Crack a vent, run the roof fan on low, and expect to wipe down windows in the morning. Losing a little heat on purpose is cheaper than replacing insulation, and it is the same habit that keeps the numbers in the first section from applying to you.

Assume the services are closed

Winter closes the infrastructure before it closes the roads. Yellowstone’s campground page states that dump stations, where available, may close when temperatures are below freezing, and lists most of its campgrounds with seasons that end in September or October. Only Mammoth is listed as open year round.

Plan on the nearest dump station and potable fill being shut, and call to confirm rather than driving to find out. Dump stations and fresh water covers how to build that into a route. Our water management guide is written for the desert problem, but the same discipline of knowing your next fill before you need it applies harder in winter, when half the taps are off.

Where you camp still runs on posted rules

None of this changes the legal picture. Stay limits, closures, and overnight restrictions apply in January exactly as they do in July, and winter adds seasonal gates and road closures on top. The posted sign and the land manager’s current guidance beat this page and every other page. If the gate is closed, it is closed, whatever the map says.

If your winter plan is to leave the cold instead of engineering around it, that is the more common answer, and snowbird routes explains how that migration works. If you are going up rather than south, read when the high country opens first, because the road you want may not be plowed until well into summer.