Just purchased a new Roomster SE TSI 105

The AC comes on automaticially if you place the regulator of air distribtuion switch to the upright position - demist - also when you press the AC switch the recirculation switch also illuminates and turns on.

This never happened with my old Roomster. I contacted the dealership who informed me that this is a new feature, although it is not shown in the owner's manual. Also quite why you would want to send AC air onto a windscreen to demist it in winter is beyond me.

Has anyone else had this and is it a new feature?

Also quite why you would want to send AC air onto a windscreen to demist it in winter is beyond me.

Because the air conditioning produces drier air which picks up more moisture from the glass, clearing the windows more quickly.

It is quite a common feature.

You will also notice that when you have your fan at any posistion (1, 2, 3, or 4) even if a/c compressor is off and shift in reverse then the recirculation button (and its functions) get activated to prevent gas fumes enter the cabin.

Also if it rains and you have your wipers on and shift in reverse then your rear wiper will also gets activated.

Both a Focus and Micra I owned had the auto aircon 'on' feature when turning the airflow to windscreen, but my 2008 Roomster doesn't, though on selecting reverse gear, the re-circulation does activate. I don't understand the re-circulation activating when pressing the AC button, that's usually on cars which have an AC Max button. I could understand if it was an intelligent Climate Control system, and you selected a low target temperature on a hot day, it could recirculate for a short time until the temperature got closer to the set target. Try pressing the AC button with the heat set to hot and see if the recirculate still comes on.