How to Install an Espar Heater in Your Van

If you're building a van for anything beyond summer weekend trips, you need a real heating system. A space heater running off your inverter drains batteries fast. Propane buddy heaters produce moisture and require ventilation. An Espar (now branded as Eberspacher) combustion heater solves all of this — dry heat, low power draw, and enough BTUs to keep you comfortable in genuinely cold conditions.

We install Espar heaters on most builds at our San Diego shop, and they're consistently the system that owners say they're most glad they invested in. This guide covers how they work, which model to choose, the full installation process, and real-world performance data from builds we've completed.

Why Is Espar the Best Heater for Van Conversions?

We've tested and installed several heating options. Here's why Espar is our go-to:

• Dry heat: No moisture added to the air. This matters enormously for condensation management — the biggest ongoing challenge in any van.
• Low power draw: 1–4 amps running means your batteries last. Compare that to a ceramic space heater on an inverter pulling 100+ amps from 12V.
• Reliability: Espar has been making vehicle heaters for decades. These are OEM equipment on commercial trucks and emergency vehicles. They're built for continuous use.
• Altitude compensation: The newer models auto-adjust for altitude, which matters if you're at 8,000+ feet in the mountains.
• Quiet operation: At low settings, you barely hear it. The fan hum is about the same as a vent fan on low.

How Do I Install an Espar Heater in My Van?

1. Plan the Mounting Location

Most van installs mount the heater unit under the vehicle. This keeps the combustion unit completely outside the living space. The heater mounts to a bracket on the undercarriage with ducting running up through a hole in the floor.

Some builders mount inside a sealed exterior compartment or inside the van in a sealed box with external intake/exhaust. Under-floor is cleaner and is what we recommend.

2. Install Intake and Exhaust

The combustion air intake and exhaust are critical safety items. Both pipes must exit to the exterior where exhaust fumes cannot re-enter the van. Route exhaust away from windows, sliding doors, and any fresh air intakes. Follow the manufacturer's minimum pipe lengths — too short and you get poor combustion. Too long and you restrict airflow.

The exhaust pipe gets hot. Use proper heat shielding where it passes near plastic, rubber, or anything flammable.

3. Run Interior Ductwork

From the heater outlet, run 60mm or 75mm flex ducting through the floor and into the living space. Where you terminate the duct determines where the heat goes. Options:

• Single outlet: Simplest install. One vent near the center or foot of the bed area.
• Y-splitter with two outlets: Better heat distribution in longer vans. One vent toward the sleeping area, one toward the living/kitchen area.
• Under-floor ducting: Runs under the subfloor with multiple floor vents. More complex but gives the most even heat distribution.

4. Connect the Fuel Line

Diesel models: A fuel standpipe inserts into the vehicle's diesel tank through the fuel sender opening. The heater's dosing pump draws fuel through this line. The standpipe sits about an inch above the tank bottom so it won't drain your fuel completely.

Propane models: Connect to a dedicated propane tank (typically 5–20 lb) with a proper regulator. The propane version is more common in gas-engine vans since you don't have diesel on board. Propane consumption runs about 0.1–0.3 gallons per hour depending on the heat setting.

5. Wire the Electrical

Run a dedicated fused 12V circuit from your battery bank to the heater. Use 10 AWG wire for runs under 15 feet. The heater needs a clean ground — vibration and corroded grounds cause more Espar issues than anything else.

Wire the controller or thermostat connection to your desired location inside the van. Most people mount the controller near the bed or in a central location.

6. Install the Thermostat/Controller

The EasyStart Pro is the standard controller. It gives you temperature display, programmable timers, and diagnostic codes. You can also use an aftermarket thermostat or Espar's smartphone module for Bluetooth control.

Set it up where you can reach it from the bed. Nothing worse than having to get out from under the covers to adjust the heat at 3 AM.

7. Test and Break In

Run the heater through its initial cycle. Expect some smoke and smell for the first few runs as manufacturing oils burn off — this is normal. Check for exhaust leaks at every connection point. Verify the combustion air intake isn't restricted. Confirm the thermostat reads accurately and the heater cycles on and off correctly.

Should I Get a Diesel or Propane Espar Heater?

If your van runs on diesel (Sprinter, Transit diesel), a diesel Espar is the obvious choice. You tap into the vehicle's fuel tank and never need to carry a separate fuel source. One fuel system for everything.

If your van runs on gas (ProMaster, gas Transit), you'll need a propane Espar since the heater can't burn gasoline. This means carrying a propane tank — typically a 5 or 20 lb tank mounted in a ventilated exterior compartment or under the van. A 20 lb tank gives you roughly 50–70 hours of runtime at moderate settings.

The SoCal Perspective

Building out of San Diego, a lot of our customers think they don't need a heater. Then they drive to Joshua Tree in December, Mammoth in March, or up the coast to Big Sur and realize how cold a van gets overnight.

Even in Southern California, nighttime temperatures drop into the 40s and 50s in winter — and that feels cold in a metal box. If you're doing any mountain trips, desert camping in fall/winter, or traveling up the coast, a heater transforms the experience. We recommend it on almost every build.

Do I Still Need Ventilation When Running an Espar Heater?

Even though an Espar heater doesn't introduce combustion fumes into your living space, you still need ventilation when running it. Two people in a sealed van produce CO2 and moisture from breathing alone. Crack a window slightly or run your vent fan on the lowest exhaust setting to maintain fresh air exchange.

Also install a CO detector in every van — not because the Espar produces CO inside (it shouldn't), but as a safety backup in case of any malfunction. A good CO detector is cheap insurance.

For a full look at how heating fits into your overall climate system, see our heating systems guide. And if you're planning an off-grid setup, an Espar's low power draw is a major advantage over electric heating options.