I don’t use night heaters, if I’m tramping I have a massive quilt and a sleeping bag if need be.
But, I’m parked up for 6 hours waiting for the ferry.
There’s one vent near the passenger door which is more like a radiator than anything else as little comes out. The main vent behind the passenger seat, comes out at the bunk and just blows under the passenger seat. This has an inverter behind the seat.
Should there be a pipe or something aiming up? This just fires it under the passenger seat to be lost forever.