What’s the difference between the Air 2D and Air 4D RV diesel heaters?

Published 08/11/2025

Products Featured in This Question

Autoterm Air 2D Diesel Heater for Vans, Campers, Trucks, and Boats - 12v

$985.50

Autoterm Air 4D Diesel Heater for RVs - 12v

(1)

$1169.36

Question:

We’re torn between the 2D and 4D for our van. Is the 4D overkill, or worth it?

asked by: Sam

Expert Reply:

Sam, the Air 2D # AU56MR heater is ideal for smaller vans, campers, and boats. It draws less fuel and power. But if your van is larger, or you’re heating multiple areas, the 4D # AU96MR heater gives you more airflow and faster warm-up. It also cycles less in cold conditions and is quieter at partial loads.

Think of the 4D as the bigger version with bigger lungs for more air to get through to you. It also performs at higher elevation.

For the small price difference, I'd lean towards the 4D if I were you. I don't know how many times I regretted just shelling out another $50 or $100 on something since in the long run it is more benefical.

expert reply by: Andrew N