The air curtain unit includes a fan (5) and a filter (4) in a casing (1) with air induction apertures (2) and air outlet apertures (3). The surrounding air can be heated to a preset temperature. A radiant plate (6) is also fitted and may use warm water for heating. The heater may form part of the casing. It may run between the air induction apertures and the air outlet apertures. The radiant plate may be heated by means of electricity, or it may have hot water circulated through it to heat it.
