Furniture and Furnishings - covering a radiator for seating

Does anyone know if a cast iron radiator can be covered to be used as seating or will it always be too hot.

All of the active radiators I'm familiar with have been too hot. Covering them would present a fire hazard.

Foil covered bubbled pack insulation is very effective insulation around a radiator. Build the seat level with the window sill (I am assuming that the radiator is right under the window). Use hard wood for the seat and legs. Use the insulation behind the radiator on the outside wall and under the wooden seat. If the seat is fixed in place, you can wrap the insulation up the wall and under the seat. If you build with solid sides instead of legs, insulated the sides. This will send all the radiator heat into the room instead of right up the front of your cold window.