The air comes into contact with the heating element or the surface of the panel. The air's temperature thus rises, generating a natural convection flow.  

This category of heaters includes convection heaters and radiant panel heaters. These appliances heat the environment noiselessly and without emitting light:  

they are therefore ideal for the bedroom (quiet, no light emitted) or rooms where draughts are not desirable (powders or extremely volatile substances, or other factors).