Radiate heat: "Wrap a piece of plywood in foil and tuck it behind a radiator to reflect heat into the room." -- In my home I've used (hid) a 'car's windshield reflective sunscreen' behind my sofa to protect the fabric from the heat of a baseboard heating system (older home)- Doing this has, also, served to direct the heat up over the sofa into the room.
