Device (1) for radiating UV and/or IR in a humid room, a housing (2) and radiation units (3) having radiation sources (4) and reflectors (5) covered by radiation transmitting walls (6,7). A cooling circuit comprises an inlet (9), a front channel (10), including the space (8) between the radiation transmitting walls, and a rear channel (11) between the radiation units and the walls (14) of the housing. An exhaust ventilator (15) is provided to remove, via a channel outlet (16), cooling air (17). A double-acting protective valve (18) is provided, arranged to close both the channel inlet and the channel outlet when the exhaust ventilator is off, and/or to open the channel inlet and the channel outlet when the exhaust ventilator is on.
