temp. problem - thermostatic radiator valve options?
I have a one-pipe steam system. In the winter we have a problem where the 2nd floor occasionally gets too hot because the one thermostat is on the first floor.
I've read that thermostatic radiator valves are the solution, but I've seen two types, ones that are installed in place of the existing supply valve or the air vent. Is one type preferred over the other? It seems like the air vent type is easier to install.