Avoid placing newspapers, drying wet clothes, etc. on the grille above the convector. Thick carpets or carpets laid up against the air intakes on the furniture will prevent supply air getting to the convectors.
Don’t fill the upper cabinets in such a way that hinders air circulation. Condensation may form in the cabinets if there is poor or no circulation. When camping in winter, your pillows might even freeze to the outer wall.
Try not to place pillows, duvets and suchlike on top of the circulation openings. If circulation is prevented, the warm air barrier will disappear and you’ll get cold draughts from the windows.
This is how it should be when the hot air from the convectors flows up behind the sofa and upper cabinets:
