Heating ducting

Heating ducting is the corrugated aluminium or composite Ø 60–90 mm tubing that distributes hot air from a blown-air heater to outlet grilles around the habitation area. Layout, length, and outlet count drive how evenly the rig heats up.

Rules of thumb: total length ≤ 12 m and up to four outlet grilles for a single Truma Combi 4. Each Y-fitting cuts flow by ~30 %. Place outlets near floor level (warm air rises) — into footwells by the seats, the washroom, and lockers (to keep them dry). Excessive bends and constrictions cut efficiency badly. For winter stays, leave locker and underseat outlets slightly open.