Espar Airtronic M2 D4R
#11 in SplitFull review
For motorhomes and boats with long, branching duct runs that a standard 4 kW heater can not push through. Otherwise the D4L is cheaper and draws less power.
Amazon $1,849.99$1,849.99
3.1/5
For 24V trucks, buses and larger motorhomes that need a type-approved 5 kW heater with automatic altitude adjustment. It costs far more than clone heaters of the same size.
- 5.5 kWHeat output
- 0.18 to 0.67 L/hFuel burn
- 15 to 130 WPower draw
- ECE R122Type approval
Check price at Amazon$1,697.89
Price checked October 30, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- Type approved to ECE R122 for vehicle installation
- Adjusts itself for altitude up to about 7,200 ft
- Enough heat for a large motorhome, bus or boat cabin
- Low 15 W draw on its lowest setting
Cons
- Expensive at about $1,700
- Its top 5.5 kW Boost setting lasts only 30 minutes at a time
- The listing does not say which controller is in the kit
- 24V only in this kit, so most vans and RVs need the 12V version
The Webasto Air Top EVO family
Every Webasto Air Top EVO model we rank, smallest first. Ratings compare each against its own type.
| Model | Heat output | Rating | Price |
|---|---|---|---|
| Webasto Air Top Evo 40 | 4 kW | 3.1/5 | $1,945.95 |
| Webasto Air Top Evo 55 (this one) | 5.5 kW | 3.1/5 | $1,697.89 |
How it scores
The rating comes from 6 measured or published factors, each scored 0-100 against fixed reference points for its type. How we rank explains each one.
Specifications
| Model number | Air Top Evo 55 diesel 24V kit (4111390A) |
|---|---|
| Heating | |
| Heat output (maker) | 5.5 kW |
| Lowest output | 1.5 kW |
| Fuel burn | 0.18 to 0.67 L/h |
| Build | Split (installed) |
| Power | |
| Supply | 24V |
| Running draw | 15 to 130 W |
| Controls and safety | |
| Thermostat | Yes |
| Automatic altitude | Yes, to 7,220 ft |
| CO shutoff | No |
| Type approval | ECE R122 |
| Build | |
| Dimensions | 16.7 x 5.8 x 6.4 in |
| Weight | 13 lb |
| Released | 2014-10 |
Alternatives in this type
Hcalory UNIT 2 8kW Diesel Heater
#12 in SplitFull review
A well-featured split heater for van and RV builds that want automatic altitude handling and a big tank; expect about 3 kW of real heat, not 8.
Amazon $169.99$169.99
VEVOR XMZ-D2 2kW Bluetooth Heater
#14 in SplitFull review
A small, cheap split heater with Bluetooth control and automatic altitude adjustment, sized for cars, small vans and boat cabins.
Amazon $99.90$99.90
Compare
Compare the Webasto Air Top Evo 55 with any other diesel heater →
More from Webasto: every Webasto product ranked.