Abstract: A panel (10) for a suspended heating and/or cooling ceiling comprises a flat metal cassette having mutually spaced upper and lower metal sheets (11, 12) defining a sealed space (17) therebetween. The metal sheets are perforated by registering apertures (13, 14) which are sealed against the space along the circumference thereof. At least one of the metal sheets around each aperture forms an embossment (15) attached to the other metal sheet as a spacer between the metal sheets. An inlet (19) and an outlet (20) communicate with the space for circulating a fluid heat carrier through the space in heat exchanging relationship with the panel.