Autoterm Air 2D
#3 in SplitFull review
For van and boat owners who want a type-approved 2 kW heater for less than Webasto or Espar. Add a timer panel if you want it warm before you wake.
Amazon $949.99$949.99
3.4/5
For larger vans, trucks and boats that need a type-approved 4 kW heater that works anywhere, including high mountain passes. It costs far more than clones but is built for years of daily use.
- 4 kWHeat output
- 0.12 to 0.49 L/hFuel burn
- 6 to 37 WPower draw
- ECE R122Type approval
Check price at Amazon$1,675
Price checked October 30, 2026. As an Amazon Associate we earn from qualifying purchases.
Older model: this replaces the Espar Airtronic M2 D4L (rated 3.4). See every Espar Airtronic 3 generation.
Pros
- Type approved to ECE R122 for vehicle installation
- Adjusts itself for altitude up to about 18,000 ft
- Draws 6 to 37 W, less than the M2 it replaces
- Enough heat for a large van, sleeper cab or small motorhome
Cons
- About $1,675 for 4 kW
- The listing does not say which controller is in the kit
- Needs a proper install with fuel standpipe and exhaust
The Espar Airtronic 3 family
Every Espar Airtronic 3 model we rank, smallest first. Ratings compare each against its own type.
| Model | Heat output | Rating | Price |
|---|---|---|---|
| Espar Airtronic S3 D2L | 2.2 kW | 3.5/5 | $1,250 |
| Espar Airtronic M3 D4L (this one) | 4 kW | 3.4/5 | $1,675 |
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 | Airtronic M3 D4L 12V (25.2955.05.0000) |
|---|---|
| Heating | |
| Heat output (maker) | 4 kW |
| Lowest output | 1.1 kW |
| Fuel burn | 0.12 to 0.49 L/h |
| Build | Split (installed) |
| Power | |
| Supply | 12V |
| Running draw | 6 to 37 W |
| Starting draw | 105 W |
| Controls and safety | |
| Thermostat | Yes |
| Automatic altitude | Yes, to 18,050 ft |
| CO shutoff | No |
| Type approval | ECE R122 |
| Build | |
| Dimensions | 14.8 x 5.5 x 5.9 in |
| Weight | 9.9 lb |
| Released | 2021 |
Alternatives in this type
Espar Airtronic S2 D2L
#4 in SplitFull review
For van and truck owners who want a type-approved 2 kW heater with low power draw and a timer. The newer Airtronic S3 D2L now does the same job for less.
Amazon $1,315$1,315
Espar Airtronic M2 D4L
#6 in SplitFull review
For larger vans, sleeper cabs and boats that need a type-approved 4 kW heater with a wide turndown. The M3 D4L that replaces it costs the same and draws less power.
Amazon $1,675$1,675
Compare
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