Heat is the one RV system where the fuel question really matters. An electric heater is useless without shore power. A propane furnace burns through tanks in cold weather and draws a surprising amount of 12 V power for its blower. A diesel air heater sips fuel and battery but adds a second fuel to carry. Here is how the three compare on the things that decide whether you are warm at 2 a.m. with no hookups.
The three options
Electric heat. A ceramic space heater or a heat-pump air conditioner running on 120 V AC. Silent-ish, no combustion, no fumes, and only practical on shore power or a generator. The Dometic Penguin II 15,000 BTU ($799.00) is a rooftop unit available in heat-pump form; a portable PTC ceramic heater ($23.20) is the cheapest way to add warmth at a pedestal.
Propane furnace. The ducted forced-air furnace most North American RVs ship with. Burns LP from the onboard tanks, exhausts outside, and uses a 12 V blower.
Diesel air heater. A compact combustion heater that burns diesel from its own small tank or the vehicle's tank, exhausts outside, and pushes heated air through a duct. Common on Black Series HQ campers and overland trailers. The 12 V 8 kW Bluetooth diesel air heater ($228.00) is the type we sell most, with a 12 V digital thermostat controller ($24.99) as the usual upgrade.
Side by side
| Electric | Propane furnace | Diesel air heater | |
|---|---|---|---|
| Works off-grid | No (generator only) | Yes | Yes |
| Fuel carried | None | LP cylinders you already have | Diesel, separate from LP |
| Battery draw | None (AC) | Blower: several amps at 12 V while running | Glow plug on start, then low fan draw |
| Noise inside | Fan noise | Blower plus ignition thump | Fan; pump ticking is the usual complaint |
| Noise outside | Low | Low | Exhaust hum, quieter with a muffler |
| Moisture added indoors | None | None (vented) | None (vented) |
| High-altitude behavior | Unaffected | Furnace may need altitude-rated parts, depending on the model | Better units adjust fuel mix automatically |
| Maintenance | None | Annual burner inspection | Glow plug, fuel filter, carbon cleaning |
| Combustion safety | None | CO and LP detector required | CO detector required |
| Typical install cost | Lowest | Factory-fitted or expensive retrofit | Moderate DIY |
Fuel-consumption and amperage figures vary a lot by model and output setting. Use the manufacturer's numbers for the unit you are installing rather than a generic rule.
Electric: fine at the pedestal, useless without it
If you camp with hookups, electric heat is the cheapest and cleanest. The campground pays for the fuel. A 1,500 W ceramic heater is the standard, but keep in mind that on a 30 A site it eats 12.5 A of your 30 A budget, so running it with the water heater and microwave will trip the pedestal breaker.
Off-grid, electric heat is a non-starter. A 1,500 W heater draws roughly 125 A from a 12 V bank through an inverter. Even a 280 Ah lithium bank gives you two hours. Heat-pump air conditioners are more efficient but still not practical from batteries overnight.
Propane furnace: convenient, thirsty, and blower-hungry
The propane furnace's advantage is that you already carry the fuel and the unit is already installed. Its two weaknesses show up in cold weather:
- Fuel use. A furnace on a freezing night can empty a 20 lb cylinder in a couple of days. An automatic changeover regulator ($78.00) at least means you do not wake up cold when one tank runs dry.
- 12 V draw. The blower runs whenever the furnace does. Over a cold night that is a meaningful chunk of a lead-acid bank and a noticeable one even for lithium.
Propane also has ignition and altitude quirks, and everything about it depends on a working LP/CO detector ($44.99).
Diesel air heater: the off-grid favorite for a reason
Diesel heaters became standard on off-road campers because they solve both furnace problems. Fuel burn is low, and once the glow plug finishes its start-up cycle the only draw is a small fan and the fuel pump. That is why a well-insulated Black Series HQ can run one for a week on a small tank and a modest lithium bank.
The tradeoffs:
- A second fuel. If your tow vehicle is gasoline, you are carrying diesel separately. A Wavian 20 L diesel jerry can is the right container; do not use a gasoline can.
- Start-up cycle. The glow plug draws heavily for a minute or two at start. Not a problem for lithium; a marginal lead-acid bank can struggle.
- Pump ticking. The metering pump clicks. Mounting it on rubber and orienting it as the manual specifies reduces it.
- Carbon build-up. Running on low output for long periods soots the burner. Run it on high for a while each trip.
- Altitude. Cheaper units lean out badly above about 5,000–8,000 ft and smoke or shut down. Units with automatic altitude adjustment, like the one linked above, handle this; older ones need a manual setting or an altitude kit.
Install notes: the exhaust must exit under the RV away from windows and vents, the intake and exhaust must not share a compartment with the heated air, and the unit needs a fused 12 V feed sized for the glow-plug start current. Every diesel install needs a working CO detector inside; a dual LP/CO 12 V alarm ($42.00) covers both fuels if you also carry propane for cooking.
Combining them
Most experienced owners run two: electric at the pedestal (free heat), and diesel or propane off-grid. If your RV has a propane furnace and you spend serious time off-grid in cold weather, adding a diesel heater is the single upgrade most likely to change how long you can stay out. If you rarely leave hookups, a good electric heater and the furnace you already have are enough.
For the electrical side of a diesel install, including fuse and wire sizing, see the installation requirements guide. For keeping water lines from freezing while the cabin is warm, heat tape and tank heater pads are the usual add-ons.
Shop this
- 12V 8kW Bluetooth Diesel Air Heater — $228.00
- Diesel Heater Thermostat, 12V Digital — $24.99
- Automatic Changeover LP Regulator Kit — $78.00
- Portable PTC Ceramic Space Heater — $23.20
- Dometic Atwood 31011 CO & LP Detector — $44.99
- Propane/Gas (collection)