Even when the mercury dives and frost creeps across the windows, this heater keeps large cabins, cargo bays, and berths livable. The Autoterm Air 4D is for those who travel year-round and depend on gear that works long after the weather quits cooperatin g.
You climb into the van after a day in the cold, and the air inside cuts straight through your jacket. The Air 4D was built for that exact kind of night. It supplies up to 168 cubic meters of heated air per hour, nearly double the output of Autoterm's 2D, for larger campers, trucks, and boats. It's efficient, dependable heat that makes wide, cold spaces livable again, or at least a place you won't dread attempting to sleep in. From motorhomes to boats up to 48 feet, the Air 4D delivers serious output without burning serious fuel. With airflow up to 1,800 square feet per hour and smart power draw, it heats medium to large interiors efficiently so you can travel further between refuels.
Whether you're parked near treeline or chasing elevation for snow, the Air 4D is already calibrated for it. Tested to -49 F and rated for 13,780 ft, it maintains efficient combustion without manual tuning or part changes. You don't need to tweak settings or swap parts. Just fire it up and get comfortable, even in the thin air of high camps and remote mountain spots.
Once it's running, the Air 4D holds your set temperature steady and stays consistent through long runs. Use the included control panel for quick adjustments, or add the optional QSTART modem (not included) if you'd rather handle it from your phone. For more control, pair it with an optional external temperature sensor that lets you fine-tune cabin temps from inside your shelter (pictured below, not included). 
Everything you need comes in the box, including hardware, ducting, and clear instructions, so setup feels like a project you'll actually finish. Its self-cleaning burn cycle and sealed design keep maintenance low.
The Air 4D keeps output stable when temperatures collapse and altitude climbs. The brushless induction motor moves air quietly through long freezes, and the steel housing with sealed electronics resists vibration, salt, and road grit. From frozen trailheads to offshore runs, performance stays consistent even when conditions don't. If the Air 2D keeps small rigs and tight builds livable, the Air 4D takes that same dependability and scales it up for full-size vans, motorhomes, and boats. Same cold-tested endurance. Just more of it.
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