Which door stopper for the heating room?

Hello,

a few months ago I got new room doors and today the chimney sweep was here. He said I would have to have a ventilation grille installed in the door of the heating room or have a door stopper installed at the height of the lock. This should be removable.

Can anyone tell me which door stopper is meant, how much something like this costs, and what it looks like?

Thanks!

Sounds like the door in the open position is preventing necessary air circulation. If that is the case, screwing any workpiece (doorstop, sawed-off table leg, wooden block) to the door would be sufficient, provided the necessary distance to the heater is ensured by the door stop when the door is open. If it is about fire protection, since the door must not come too close to the heater when open, the doorstop must of course be made of non-combustible material if it protrudes into the "danger zone". Ask again about the purpose of the action.

It is probably about the ventilation (however, there are also two windows to be opened in the room). I will still receive the protocol.