Portable Diesel Heater for RV: The Complete Decision Guide (Apollo-P1 vs P2)

A portable diesel heater for an RV makes sense when you camp off-grid, sleep in different vehicles, or want safe heat in a tent. We sell two models at rvheater.com — the Apollo-P1 (2.5KW) and the Apollo-P2 (5KW). Both run on 12V from your battery and 110V/230V at the campsite, rated to -40°F (-40°C), E-mark certified.

If your rig has a permanent diesel tank and you camp in one place all winter, a fixed-mount heater wins. If you bounce between a van in March, a wall tent in October, and a Class C in December, the portable wins. This guide covers sizing, setup, safety, and the gap between "all-in-one" marketing labels and what the spec sheet actually says.

When a Portable Diesel Heater Makes Sense for Your RV

A portable diesel heater wins in three RV scenarios: you don't own the vehicle, you switch rigs across seasons, or you boondock without shore power for more than two nights at a time. If none of these apply, a fixed-mount heater costs less per BTU and runs just as clean.

The rest of this section walks through the trade-offs against propane and electric so you can make a clean call before checkout.

Quick decision:

Portable vs. Fixed-Mount Diesel Heaters

Fixed-mount diesel heaters tap into your existing vehicle tank and disappear under a bench seat — but they live in one rig only. The Apollo-V1 and V2 burn 0.10–0.47 L/hr depending on load.

The portable version costs more upfront because it bundles its own 5L tank and weatherproof housing. The trade-off works in your favor when you don't own the vehicle.

Pick fixed-mount if:

• ✅ You own one rig and live in it for months at a time
• ✅ You want the lowest cost per BTU
• ✅ You don't mind a permanent install through the floor

Pick portable if:

• ✅ You rent or borrow vehicles often
• ✅ You switch between an RV and a tent across seasons
• ✅ You want heat in an ice shack, rooftop tent, or work truck

Portable Diesel vs. Propane Heaters in an RV

Propane combusts inside your RV — every BTU of heat comes with water vapor and CO2 added to the air you breathe. Even with a Mr. Heater Buddy's oxygen depletion sensor, those byproducts still fill the cabin.

A portable diesel unit puts combustion outside the vehicle and ducts only warm, dry air inside. You also win on runtime.

Tip: Diesel is available at every fuel station — you don't need to hunt down 1 lb propane bottles on the road.

Portable Diesel vs. Electric Space Heaters

A 1500W ceramic heater drains a 100Ah lithium battery through an inverter in under an hour. A portable diesel heater on its lowest setting runs over 80 hours on the same battery. That gap is the difference between heat for one cold morning and heat for a full week of boondocking.

Electric only works when you have shore power, a generator, or grid power at the campsite. For off-grid use, the math doesn't close.

One mistake to avoid: Don't plan a winter boondocking trip around a "portable" ceramic heater plus an inverter. By 3 a.m. your battery is dead, the cabin matches outside temperature, and your fridge has gone offline too.

Apollo-P1 (2.5KW) vs Apollo-P2 (5KW): Which Size Fits Your Rig

Pick the Apollo-P1 (2.5KW) for spaces up to 150 sq ft — vans, truck cabs, small wall tents, ice shacks. Pick the Apollo-P2 (5KW) for spaces up to 300 sq ft — Class B and C motorhomes, large outfitter tents, double-cab trucks. Both use a 5L tank, the same Kyocera ceramic glow plug, and the same patented compact housing.

Apollo-P1 (2.5KW): Compact Power for Vans and Small Tents

The P1 measures 13.4" × 13" × 8.7" (34 × 33 × 22 cm) and weighs 29 lbs (13 kg). Small enough to sit in a milk crate under a van bench or on the floor of a wall tent. At ULTRA LOW it pulls 0.77A at 12V, letting a 100Ah lithium battery feed it for over 80 hours.

Best for: vans up to 6 m (20 ft), single-cab trucks, 8'×10' wall tents, ice shacks, rooftop tents. Price: $969.99

Apollo-P2 (5KW): Full-Size RVs and Large Tents

The P2 measures 16.5" × 13.8" × 9.4" (42 × 35 × 24 cm) and weighs 35 lbs (16 kg). It puts out 5KW (16,000 BTU) at BOOST — enough to heat a Class C motorhome down to -40°F (-40°C) without running flat out.

Best for: Class B / C / A motorhomes, fifth-wheels, 12'×14'+ wall tents, double-cab trucks, garages up to 300 sq ft. Price: $1,099.99

Sizing Matrix: Match Heater to Space

Tip: When in doubt, go P2. Its ULTRA LOW setting (1.4KW / 4,900 BTU) draws only 0.144 L/hr — almost matching the P1's 0.136 L/hr. Oversizing rarely costs efficiency. Undersizing costs comfort.

One mistake to avoid: Don't size by "5KW heats anything." A 5KW unit blasting full-out in a 250 cu ft van cab roasts you in 10 minutes, then short-cycles all night. The right-sized P1 modulates cleanly across all five power steps.

Both models ship with all installation hardware in the box. → See current pricing and order on the portable diesel heater page.

What "All-in-One" Actually Means: The Apollo Portable Design

An honest all-in-one portable diesel heater bundles the combustion unit, fuel tank, pump, exhaust muffler, controller, and weatherproof housing into one carry-able case. You plug it in and go. Cheap "all-in-one" units often skip the muffler, ship a generic glow plug, or use a plastic housing that warps after one cold winter.

What Ships in the Apollo Portable Box

Every Apollo portable diesel heater comes with everything needed for a standard setup — no extra accessories to buy:

• ✅ Heater main unit in a pressed iron outer housing (weatherproof, not plastic)
• ✅ Integrated 5L fuel tank
• ✅ Fuel pump and fuel line
• ✅ Wired remote control for in-bed temperature adjustment
• ✅ Warm air duct (Ø60 mm for P1, Ø75 mm for P2)
• ✅ Exhaust pipe and muffler
• ✅ Carry handle and mounting bracket
• ✅ Power cable for 12V DC + 110V / 230V AC

The only thing you supply is the diesel. Standard #2 diesel from any fuel pump works. Kerosene runs the heater too in a pinch.

Watch the Apollo portable diesel heater walk-through — every part listed above shown on camera:

Dual Voltage: The One Spec That Sets It Apart

Most portable diesel heaters lock you to 12V only. That means you can't run the heater from a household outlet without a battery and inverter in the middle. The Apollo portable accepts both 12V DC from your vehicle battery and 110V / 230V AC directly from a wall outlet.

The 110V / 230V mode runs the heater straight off mains power — no battery, no inverter, no draw on your vehicle electrical system. That matters in three common cases:

• ✅ Garage, workshop, or barn — plug straight into a wall outlet, no vehicle needed
• ✅ Powered campsites with shore power — the heater runs directly off 110V / 230V, your house battery stays free for fridge and lights
• ✅ Tents near grid power — run an extension cord from a cabin, RV outlet, or generator to the heater

Order the 110V version for North America. Order the 230V version for Europe, Australia, or the UK. Both versions include 12V DC as standard.

Certifications That Matter

The Apollo portable is E-mark, CE, RoHS, and FCC certified — the same standards European OEMs require for vehicle-installed heaters. Cheap "all-in-one" units on Amazon and eBay often skip E-mark certification. That's why some campsites in Europe and the UK won't let them on site.

Note: E-mark is the only certification that actually tests emissions and noise. CE alone is self-declared, with no third-party emissions test.

How to Set Up a Portable Diesel Heater in an RV, Tent, or Rooftop Tent

Set the heater outside your sleeping space, run the warm air duct in through a window or door, and route the exhaust pipe away from people. Total setup time: 5–10 minutes, no tools needed for the standard configuration. The combustion unit and exhaust stay outside — you only bring warm air in.

RV Setup

For RV and van use, the goal is combustion outside, warm air inside:

1. Place the heater on level ground beside the rig, or on a non-flammable mat on the cabin floor with the exhaust routed through a window.
2. Run the warm air duct in through a cracked window, vent, or pre-cut floor port.
3. Position the exhaust pipe so it points away from doors, windows, and intake vents.
4. Plug into 12V from your house battery, or directly into shore power via 110V / 230V.
5. Fill the tank with diesel, prime the system from the LCD panel, and start the burn cycle.

Tip: A 3" (75 mm) deck port from any marine supply shop lets you pass the duct through the floor cleanly and seal it when not in use.

Tent Setup (Wall Tents and Outfitter Tents)

The Apollo portable runs safely in tents because combustion happens outside the fabric — only filtered warm air enters through the duct. No CO inside, no open flame.

The dual-duct method works best for tents larger than 10' × 12':

• ✅ Duct 1 (warm air in) runs from the heater outlet to one corner of the tent
• ✅ Duct 2 (cold air return) runs from the opposite corner back to the heater intake
• ✅ The circulating airflow evens out temperature and stops cold spots near the floor

For smaller tents (under 10' × 12'), a single warm air duct through the door zipper is enough.

One mistake to avoid: Don't route the exhaust pipe under the tent skirt. Cooled exhaust gases sink and can drift back into the tent through the floor seam. The exhaust must vent into open atmosphere, clear of any tent skirt, door, or window.

Rooftop Tent and Truck Camper Setup

For a rooftop tent on a truck or SUV:

1. Set the heater on the truck bed or ground beside the vehicle — the carry handle makes this a one-person job.
2. Route the warm air duct up to a zipper or tent vent.
3. Run the exhaust pipe horizontally away from the tent, not under it.

The same Ø60 mm (P1) or Ø75 mm (P2) duct that ships in the box reaches most 4-person rooftop tents without an extension.

Note: Always carry a battery-powered CO detector inside any closed sleeping space. Diesel combustion is clean and outside the tent, but a detector costs $20 and removes any guesswork.

Are Portable Diesel Heaters Safe? Three Reasons They Beat Propane in a Tent

Yes — portable diesel heaters are safer than propane heaters for tent and RV use. Combustion happens outside your sleeping space, and the exhaust is routed away from the air you breathe. The Apollo portable's combustion unit, fuel tank, and exhaust all sit outside the tent — only filtered warm air enters through the duct.

Where the Carbon Monoxide Goes (Diesel vs. Propane)

The physical separation is what matters. A propane heater pulls room air, burns it with propane, and pumps the byproducts back into the same room. The Apollo portable pulls outside air, burns it outside, and pushes only warm air back into the tent through a sealed duct.

Three Built-In Safety Systems

Every Apollo portable diesel heater includes:

• ✅ Automatic shutdown on overheat — the controller cuts fuel and runs the fan to cool the combustion chamber if internal temperature exceeds the set limit
• ✅ Altitude compensation up to 11,483 ft (3,500 m) — the EasyStart Pro controller adjusts the fuel-air ratio so the unit doesn't run rich at elevation
• ✅ Sealed combustion chamber — no flame contact with cabin air, no open pilot light

The same systems are required on all E-mark certified vehicle heaters in Europe. Cheap "all-in-one" units sold without E-mark certification often skip altitude compensation. That's why they put out black soot and elevated CO at higher elevations.

What Could Still Go Wrong (And How to Prevent It)

One mistake to avoid: Don't seal the warm air duct port into the tent fabric so tightly that the duct can't slip. If the duct disconnects at the heater outlet at 3 a.m., the heater keeps running but no warm air enters the tent. A small amount of exhaust could also be pulled into the cold air return.

Tip: Carry a battery-powered CO detector ($15–$25 on Amazon) and place it inside the tent near your sleeping bag. The Apollo's safety design makes this redundant in normal operation, but a $20 detector eliminates all guesswork.

How a Portable Diesel Heater Performs in the Real World

At LOW setting, the Apollo-P1 burns through its 5L tank in about 30 hours and uses 0.93A at 12V. A single 8-hour overnight burn drains less than 8% of a 100Ah battery. The numbers below come from the heater's published fuel consumption tables and what they translate to in actual RV and tent scenarios.

Real-World Runtime Scenarios

Tip: Most users in mild winter conditions refuel every other night. In sub-zero weather running HIGH, plan on refueling daily.

12V Battery Operation Without Shore Power

A 100Ah lithium battery feeds the Apollo-P1 at ULTRA LOW (0.77A) for over 80 hours of runtime. That's 3+ nights of continuous heat without shore power, a generator, or solar.

If you camp with a 200Ah bank (common in vanlife builds), the math doubles — over 160 hours of ULTRA LOW heat from battery alone. Add solar and the heater becomes effectively grid-independent.

Note: The numbers above use ULTRA LOW current draw. Mid-load operation (LOW or MEDIUM) doubles the draw but is still well below what any modern lithium house bank can handle.

Cold Weather and Altitude Performance

The Apollo portable starts and runs reliably down to -40°F (-40°C) and operates up to 11,483 ft (3,500 m). The Kyocera ceramic glow plug is an industry-standard component used in OEM truck diesel heaters. It holds full ignition power in extreme cold, where unbranded glow plugs from budget heaters lose output and burn out within a season or two.

At elevation, the EasyStart Pro controller measures barometric pressure and trims the fuel-air ratio automatically up to 11,483 ft (3,500 m). Without altitude compensation, a diesel heater runs rich at moderate elevation, soots up the combustion chamber, and triggers fault codes.

One mistake to avoid: Don't shut the heater off by pulling power. Always let the controller run its cool-down cycle (2–3 minutes of fan after fuel cuts off). Killing power mid-burn leaves unburned fuel in the chamber and accelerates carbon buildup.

How to Spot a Real All-in-One Portable Diesel Heater

A real all-in-one portable diesel heater pairs a 5KW combustion unit with the right-sized housing, fuel system, and exhaust. Most "8KW all-in-one" units on Amazon and Bunnings sell the same physical hardware as their 5KW counterparts. The "8KW" label is marketing, not engineering.

Six Specs That Separate Real from Fake

The 8KW Marketing Trick

If an "8KW" unit fits in the same case as a 5KW unit, the rating is a sticker — not measurable output. Same combustion chamber, same fan, same fuel pump. Independent reviews routinely show "8KW" units topping out at 4.5–5KW under real loads.

The honest measurement is BTU output at the burner exit. Most budget brands don't publish this data because it would contradict the sticker.

Lifespan and Warranty Reality

A well-maintained Apollo portable runs 5–8 years before needing major service. Budget "8KW" units typically last 1–2 cold seasons before the heat exchanger cracks, the glow plug fails, or the fuel pump seizes.

When the budget unit fails, the seller is usually a drop-shipper with no parts inventory. The Apollo portable ships from rvheater.com with full warranty support and the same parts pipeline Vvkb's been running for 30 years.

Tip: Before buying any portable diesel heater, search YouTube for "[brand name] long-term review" and skip anything without a 12-month follow-up video. Cheap heaters look fine in unboxing — they reveal themselves at month 14.

Frequently Asked Questions

How does a portable diesel heater work?

A portable diesel heater pulls outside air into a sealed combustion chamber and ignites a fine spray of diesel using a glow plug. The heated air then flows through a duct into your sleeping space. The exhaust gas exits through a separate pipe that vents away from people.

The Apollo portable uses a Kyocera ceramic glow plug to start the burn cycle. It then runs continuously on five power settings — 2.5KW (P1) or 5KW (P2) at full output. A built-in fuel pump meters diesel from the 5L tank in measured pulses, which is the source of the soft ticking sound during operation.

Is a portable diesel heater safe to use in a tent?

Yes — portable diesel heaters are designed to be safer than propane heaters for tents because the combustion unit sits outside the tent. Only filtered warm air enters through a duct, and exhaust gases are vented to open air through a separate pipe.

The Apollo portable adds automatic shutdown on overheat, a sealed combustion chamber, and altitude compensation up to 11,483 ft (3,500 m). Route the exhaust pipe away from the tent skirt and don't seal the warm air duct so tightly that it could disconnect. Those two installation rules cover almost every safety scenario.

Do I need a carbon monoxide detector with a portable diesel heater?

Yes — always carry a battery-powered CO detector inside any closed sleeping space. The Apollo portable's design keeps combustion outside the tent or RV, so CO levels indoors should stay near zero during normal operation. A detector exists for the abnormal cases: duct disconnection, exhaust blockage, or wind blowing exhaust back into the cabin.

A reliable battery-powered CO detector costs $15–$25 on Amazon and runs for years on one set of batteries. Place it inside the tent or RV near sleeping bag height. CO is the same density as air and tends to mix evenly when the heater is running.

How long does a 5L fuel tank last on a portable diesel heater?

Between 8 and 37 hours of continuous runtime, depending on the heat setting and which model you're using.

At LOW (cruise), expect 22–30 hours per tank. At ULTRA LOW (overnight maintenance heat), expect 30–37 hours. At BOOST (initial cabin warm-up), expect 8–11 hours.

In practice, most users running an RV or wall tent in mild winter conditions refuel every other night. In sub-zero weather running on HIGH, plan on refueling daily. A 5L tank is light enough to lift and refill from a standard fuel jug — about 11 lbs (5 kg) of diesel when full.

Can I use kerosene or any other fuel in the heater?

Yes for kerosene, no for gasoline. The Apollo portable runs on standard #2 diesel as its primary fuel. Kerosene works as an alternative in extreme cold — it gels less than diesel below 0°F (-18°C).

Never use gasoline — diesel and gasoline heaters use different combustion cycles, and gasoline in a diesel heater damages the combustion chamber within minutes. #1 diesel (winter blend with kerosene cut) works down to -22°F (-30°C). Avoid biodiesel above B5 in cold weather — it gels at higher temperatures than petroleum diesel.

Will the heater work at high altitude?

Yes — the Apollo portable operates reliably up to 11,483 ft (3,500 m) thanks to automatic altitude compensation. The EasyStart Pro controller measures barometric pressure several times per minute and trims the fuel-air ratio so combustion stays lean and clean as elevation increases.

Above 11,483 ft, combustion efficiency drops and the heater may struggle to maintain output. Most consumer portable diesel heaters without altitude compensation start sooting up at moderate elevation. The fuel-air ratio runs rich, the combustion chamber fouls, and fault codes appear. The Apollo handles this automatically — no manual adjustment needed.

How loud is the heater at night?

Quiet — most users stop noticing it by the second night. The two sound sources are the fan and the fuel pump, both steady mechanical sounds rather than sharp or irregular noise.

The fan produces a low-frequency hush that blends into the background quickly. The fuel pump produces a soft tick every 1–4 seconds — slower at lower settings, faster at higher. Place the pump on the rubber mounts included in the box and mount it vertically a few feet from the heater; that typically cuts the audible tick by half or more. How much sound actually reaches your sleeping ear depends on installation — a unit inside a sealed cabinet on rubber mounts runs noticeably quieter than one mounted directly on a hard floor.

What happens if my battery dies mid-burn?

If the battery voltage drops below the safe threshold, the Apollo's controller stops the fuel pump and runs the fan for 2–3 minutes to cool the combustion chamber before shutting off cleanly. This protects the heater from the carbon buildup that comes from killing fuel mid-burn.

If the battery dies suddenly (a hard disconnect mid-burn), unburned fuel can remain in the chamber and contribute to carbon buildup. To avoid this, plug into shore power (110V or 230V) when the battery is below 30%, or carry a portable jump pack as backup. The Apollo portable accepts both 12V DC and 110V / 230V AC simultaneously — once shore power is connected, the heater runs without touching the battery.

Ready to Order Your Apollo Portable Diesel Heater

Two models, one product page, one warranty. Pick the Apollo-P1 (2.5KW) for vans, truck cabs, small wall tents, and rooftop tents — anywhere up to 150 sq ft. Pick the Apollo-P2 (5KW) for Class B/C motorhomes, large outfitter tents, and double-cab trucks — anywhere up to 300 sq ft.

Both include:

• ✅ Integrated 5L fuel tank, fuel pump, exhaust muffler, and wired remote
• ✅ 12V DC + 110V / 230V AC dual-voltage power — plug into any wall outlet at home or on a powered site
• ✅ E-mark, CE, RoHS, and FCC certified — the same standards required for vehicle-mounted heaters in Europe
• ✅ Kyocera ceramic glow plug, pressed iron weatherproof housing, and altitude compensation to 11,483 ft (3,500 m)
• ✅ Full warranty support and parts pipeline backed by 30 years of Vvkb diesel heater engineering

SHOP APOLLO PORTABLE DIESEL HEATER →

If you camp in one vehicle full-time and want the lowest cost per BTU, look at the fixed-mount Apollo-V1 and V2 diesel air heaters instead — they tap into your existing diesel tank and disappear under a bench seat.

Related Guides

• Diesel Heater for Camper: Complete Owner's Guide — the pillar guide covering all camper heating options (fixed and portable, air and water)
• How to Install an Engine Block Heater (Step-by-Step DIY) — for cold-weather starts on diesel trucks and RV tow vehicles, an engine block heater complements your cabin heater