This thing on the end of a radiator consists of a valve body that screws into the normal tapping, with an air vent and an actuator screwed into the body. They look a bit bulky, but are quite effective ...

Michaels Energy - Easy fix for wasteful steam systems Thermostatic radiator valves could provide a welcome boost. By Jonathan Hilyard, LEED GA. January 23, 2013. In an age when a three-year-old cell ...