Cold, heat and damp

A gallon is a fixed amount of heat

A gallon of propane holds 91,452 Btu (US Energy Information Administration). So a furnace rated 30,000 Btu an hour burns about a third of a gallon for every hour its burner runs. A colder night means more hours. No maker publishes how long a furnace burns on a cold night, so start with a guess and watch the gauge. The last line of the sum shows the floor: a burner that never stops.

The furnace fan runs on the 12-volt battery. When the battery runs down, the heat stops, and so does the propane leak detector: one maker’s manual says the detector will not work without 12-volt power (Keystone owner’s manual, 2027).

We found no standard behind the words. Each maker sets its own range and tests it its own way, when it says how at all.

We found no independent test of any of these packages: no government lab, no university, no consumer group. Ask the maker how its rig was tested, and plan for nights colder than its number.

Warm air has to reach the water lines, or they freeze. And read the warranty for the weather: the six makers’ warranties and manuals we read all leave out damage from condensation (Jayco, Keystone, Grand Design, Forest River, Heartland and Northwood). Keystone’s and Grand Design’s also leave out damage from extreme cold, and Jayco’s leaves out acts of weather.

People put water into the air. A family of four can add up to three gallons a day in a rig, from breathing, cooking, bathing and washing (Keystone). In cold weather it lands on the coldest surfaces: windows, outside walls, the backs of cabinets.

Keep indoor humidity below 60 percent, ideally between 30 and 50 (EPA), and lower when it is very cold outside: at 0 degrees, no more than 25 percent (EPA, from the heating engineers’ society). A cheap humidity gauge tells you where you are.

• Run the fan nearest the shower or the stove while you use it, and open a roof vent.
• Dry wet clothes outside the rig, not in it.
• Leave cabinet and closet doors partly open so air moves behind them.
• If that is not enough, run a dehumidifier.
• Dry anything that gets wet within 24 to 48 hours, before mold starts (EPA).

The first four come from Keystone’s own advice to its owners.

Carbon monoxide alarms should be used in RVs, and the RV industry’s own standard requires them in motor homes and trailers (Consumer Product Safety Commission). The makers’ manuals say to test the alarm at least weekly while you use the rig.

Never heat with the range or the oven. The safety commission says it of every home, and RV makers print it in their manuals. Do not run a portable fuel-burning heater where people sleep (CPSC); Heartland’s manual says not to add one to the furnace at all. Do not run a generator while people sleep (Northwood owner’s manual).

Keep snow off the furnace’s outside vent (Northwood and Suburban manuals), and shut off the propane while you drive (National Park Service).

An RV air conditioner cools the air it takes in by about 20 degrees at most (Keystone owner’s manual; Heartland’s says 18 to 22 degrees). So if the air inside reaches 110 degrees, the best it can send out is about 90, in Keystone’s own example. Heartland says use above 80 degrees needs more equipment.

A closed vehicle heats up fast, and the National Weather Service says it is never safe to leave a child, a disabled person or a pet locked in a car (NWS). We found no government page about heat inside an RV. So ask before summer: if the power or the air conditioner stops at three in the afternoon, where do the people and the pets go?

Neither a vehicle nor a mobile home is safe in a tornado (NWS). The weather service tells people in a mobile home to move to a sturdy building before high winds arrive (NWS); it does not name RVs. Wherever you park, know where the nearest one is and how you would get there at night.

Add your propane month to the “Internet, mail, laundry, propane” line in a month on wheels, beside the rent. Then try the rig in the worst month you would live in it, before you buy.