How Much Propane Will You Burn? Planning RV Heat for Fall Nights in the East Mountains

Ask ten RVers how long a tank of propane lasts in cold weather and you’ll get ten answers, usually followed by a story about running out at 2 a.m. The honest answer is that it depends on three numbers you can find out in ten minutes: your furnace’s rating, how often it runs, and how much propane you actually have. Once you know those, you can plan instead of guess, and that matters more at 6,000 feet, where the nights get cold early.

Start With the Math (It’s Simple)

Propane contains about 91,500 BTU per gallon, a figure that appears across industry references, including a standard fuel-energy table on Wikipedia. A furnace’s rating is in BTU per hour, so gallons per hour is the rating divided by 91,500. A 30,000 BTU furnace running nonstop burns about 0.33 gallons an hour. One RV propane guide notes that RV furnaces generally range from about 10,000 to 40,000 BTU per hour, with smaller trailers and vans at the low end and larger motorhomes higher.

But furnaces cycle on and off. What you really want is the duty cycle, the fraction of time the furnace is actually running. That depends on outside temperature, your insulation and your thermostat setting, and no one can give it to you in advance. So here’s a table of estimates, my own arithmetic from the numbers above, for gallons per 24 hours at different duty cycles.

These are rough, for heating only, and assume the furnace’s input rating. Your water heater and stove burn propane too. A 50 percent duty cycle is plausible on a genuinely cold night, but I can’t tell you what yours will be, so treat the table as a range to bracket your own readings, not a prediction.

How Much Propane You Actually Have

Tanks are labeled in pounds, but your furnace math is in gallons. The RV guide I found says a 20 lb tank holds about 4.7 gallons and a 30 lb tank about 7, reflecting the standard fill limit of about 80 percent. A rig with two 30 lb tanks has roughly 14 gallons, minus whatever’s already gone. At a 30,000 BTU furnace and a 50 percent duty cycle, that’s about 3.9 gallons a day, or a bit over three days from two full tanks, before cooking and hot water. That’s why a weekend is fine and a week isn’t.

The same guide notes that tank capacity can drop sharply in extreme cold, below 0°F, and another rule of thumb it cites is 4 to 8 pounds of propane per day for heating alone in cold weather with frequent cycling. I’d treat both as rough. Check the gauge, know when your tanks were filled, and refill before you hit a quarter.

Why Elevation Changes the Picture

The park sits in Tijeras at 6,382 feet, according to the park’s own first cold nights and freeze risk guide, about 1,070 feet higher than Albuquerque. That post uses the standard rule of roughly 3.5°F cooler per 1,000 feet to estimate Tijeras runs about 3 to 4°F colder than the city on a comparable night. It also says winter nights commonly dip below freezing while daytime highs stay in the high 40s to low 50s. So your furnace does most of its work at night, and the cold arrives earlier than city forecasts suggest.

Altitude can also affect propane appliances, since thin air changes combustion. Manufacturers publish altitude guidance, and I haven’t verified your model’s, so check the manual or the manufacturer if your furnace seems to struggle. And don’t assume the Albuquerque forecast applies to your site.

Space Heater vs. RV Furnace

Many people ask whether an electric space heater is cheaper than the furnace. The answer is that it depends on your power costs, and on whether your electricity is metered or included, which is worth asking about on a monthly stay. Our monthly pricing page lists the rates, and the office can tell you how electricity is handled.

Here’s the comparison math. A 1,500-watt heater produces about 5,100 BTU an hour, since a kilowatt-hour is about 3,412 BTU. That’s a fraction of a furnace’s output, so it’s a supplement, not a replacement. On 30-amp service, which provides about 3,600 watts, a 1,500-watt heater takes over 40 percent of your capacity, leaving less for the microwave, air conditioner or hair dryer. As a purely hypothetical example, at $4.00 a gallon, propane costs about $44 per million BTU, and at $0.14 per kWh, electricity costs about $41 per million BTU. Plug in your own prices, because the result flips easily.

Carbon Monoxide and Unvented Heaters

An RV furnace is vented, which is why it’s the safer way to burn propane inside a small space. Portable unvented propane heaters are a different matter, because fuel-burning heaters can release carbon monoxide. The CPSC’s winter safety release lists carbon monoxide poisoning alongside fires as the main hazards from home heating equipment. I’m not going to tell you what’s safe in your specific rig, but I will say to test your CO alarm, replace it when it expires, and read your heater’s manual. Before you bring any supplemental heater onto your site, check the park rules and ask the office.

Reading Your Gauge, and Knowing Your Tanks

A tank gauge is a rough guide, not a precise measurement, and many RVers get caught when it reads higher than the tank actually holds. A more reliable habit is to note when each tank was filled and track how many days it lasted, which builds your own real numbers. If you use portable tanks, ask the filler how much propane they put in, and check the stamped weight on the tank, which helps you estimate what’s left. Two tanks with an automatic changeover help, since you don’t discover an empty tank at 3 a.m. A spare full tank is worth the space in a cold stretch.

Cutting Your Propane Use

You can lower the duty cycle without freezing. Lower the thermostat at night and wear layers. Close off unused spaces, cover windows with insulating film or reflective inserts, and seal drafts around slide-outs and doors. Skirting the underside can reduce heat loss, though I haven’t verified it for this park, so ask before you install anything. Use the furnace in the evening and a small, safe electric heater when you’re awake and nearby. The goal is to reduce how long the furnace runs, not to run something unsafe.

Refilling in the East Mountains

I couldn’t verify local propane fill locations or hours near Tijeras, so I won’t name a business. Call ahead, ask whether they fill tanks you bring in or swap them, and check hours, since small rural suppliers often close early. Fill before a forecast cold snap, not during it, and if you’re staying through winter, ask about delivery or a larger tank option. Our long-term living page covers what winter at the park looks like day to day.

For a stay where you can plan for the elevation, Albuquerque RV Park is where to start.

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