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.
Amazon $1,697.89The Webasto Air Top Evo 55 and the Webasto Air Top Evo 40 are evenly matched, rated 3.1 and 3.1. The Webasto Air Top Evo 55 leads on value. The Webasto Air Top Evo 40 wins on power draw. The Webasto Air Top Evo 55 costs $248.06 less ($1,697.89 vs $1,945.95).
For 24V trucks and buses that need a type-approved 4 kW heater with automatic altitude adjustment. The high price buys Webasto build quality and approval, not more heat.
Amazon $1,945.95Prices were last checked October 30, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Webasto Air Top Evo 55 for value ($309 per kW ($1,697.89, 5.5 kW) vs $486 per kW ($1,945.95, 4 kW)).
- Choose the Webasto Air Top Evo 40 for power draw (up to 55 W running vs up to 130 W running).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every split diesel heater; a clear win is highlighted. How we rank explains each one.
| Factor weight | Webasto Air Top Evo 55 | Webasto Air Top Evo 40 |
|---|---|---|
| Overall rating | 3.1/5 | 3.1/5 |
| Value 25% | 21 $309 per kW ($1,697.89, 5.5 kW) | 7 $486 per kW ($1,945.95, 4 kW) |
| Type approval 20% | 100 type approved (ECE R122) | 100 type approved (ECE R122) |
| Controls and safety 15% | 65 holds a set temperature, automatic altitude; no CO sensor | 65 holds a set temperature, automatic altitude; no CO sensor |
| Power draw 15% | 0 up to 130 W running | 11 up to 55 W running |
| Warranty 15% | 50 warranty not published (neutral score used) | 50 warranty not published (neutral score used) |
| Low setting 10% | 42 down to 1.5 kW | 42 down to 1.5 kW |
Specifications
| Webasto Air Top Evo 55 | Webasto Air Top Evo 40 | |
|---|---|---|
| Heating | ||
| Heat output (maker) | 5.5 kW | 4 kW |
| Lowest output | 1.5 kW | 1.5 kW |
| Fuel burn | 0.18 to 0.67 L/h | 0.18 to 0.49 L/h |
| Build | Split (installed) | Split (installed) |
| Power | ||
| Supply | 24V | 24V |
| Running draw | 15 to 130 W | 15 to 55 W |
| Controls and safety | ||
| Thermostat | Yes | Yes |
| Automatic altitude | Yes, to 7,220 ft | Yes, to 7,220 ft |
| CO shutoff | No | No |
| Type approval | ECE R122 | ECE R122 |
| Build | ||
| Dimensions | 16.7 x 5.8 x 6.4 in | 16.7 x 5.8 x 6.4 in |
| Weight | 13 lb | 13 lb |
| Released | 2014-10 | 2014-10 |
