Webasto Air Top 2000 STC Petrol vs. Espar Airtronic AS3 B2L

On its release, one of the biggest benefits of the Webasto Air Top 2000 STC was its unmatched fuel efficiency. Consuming a mere 0.14 liters per hour (l/h) on lower power, and only 0.27 l/h at maximum output, the Air Top 2000 STC outshone all the competition.

The Espar engineers had to put their best foot forward to beat the competition and managed to reach Webasto-level fuel efficiency with the B2L. The new laser-welded combustion chamber and dynamic heating control make the Airtronic AS3 B2L even more effective and fuel-efficient.

Although on lower powers the B2L also uses 0.14 l/h, its fuel consumption is capped at 0.26 l/h. That may not seem like a huge improvement, but when you take into account that the B2L will spend less time working at maximum capacity to achieve the same result, the difference becomes considerable.

Noise has always been a weak side for the Webasto Air Top 2000ST heaters. Both when firing up and when running for longer periods, the Air Top STC is quite noisy, with some people saying that it even interrupts their sleep. Some van lifers even opted to go for a 4KW Espar B4L instead of the Air Top 2000 STC just because of this.

Starting from the 2nd generation Airtronic, Espar has been devoted to making their heaters as silent as possible. The S2 D2L was already the quietest of its kind, which helped this diesel heater quickly become a community favorite.

All Airtronic 3 air heaters feature a new brushless motor and upgraded stepless heating control, which makes them even quieter. Some early users reported that the new B2L is up to 90% quieter than the Air Top 2000 STC, operating nearly silently for long periods of time.

With many national parks in the USA being high above sea level, being able to operate at higher altitudes is a necessity. The maximum Webasto Air Top 2000 STC altitude is 4900ft (1,500m), with anything higher than that requiring tedious manual adjustment. For those traveling at lower altitudes, the Air Top 2000 STC is perfect. But if you’re planning to hit the mountains, you’re much better off with the Eberspacher gasoline heater.

The new B2L has an integrated altitude sensor, which detects and automatically adjusts the air-fuel mixture inside the combustion chamber. This enables the 2KW Espar petrol heater to operate at altitudes up to 9,800ft (3,000m) without any additional high altitude kits. This means you’ll be able to scale the highest points in North America (excluding Denali), Europe, Australia, and Africa, without having to adjust your heater one bit.

Upgrading your heater is always a big decision, especially if you need to take your whole van apart to install a new one. If an air heater is compatible with older versions, it means that you’ll have to replace few to no parts in your system to get the heater running.

Both the gasoline model Air Top 2000 STC and Airtronic AS3 B2L have standard dimensions, meaning that they’re pretty much interchangeable. If you’re planning to replace your Air Top 2000 STC with a B2L, you might need to make your exhaust hole a few millimeters wider. Other than that, just install a new fuel line and wiring harness, mount the new heater, and you’re good to go.

The Espar Airtronic AS3 B2L has a hidden benefit. Before Espar introduced the Airtronic 3 line, a lot of van lifers opted for the last-gen Airtronic AM2 B4L 4KW petrol heater. In many cases, they did so not because they needed 4 kilowatts of heating, but because they had very few high-quality options to choose from.

Now, the B2L is perfectly compatible with the B4L peripherals. This means that upgrading to a new heater is as easy as replacing a single fuel metering pump and popping in the heater, which takes just a couple of hours at most.