we have steam radiator heat (I’m from midwest and only know forced air) – can it be changed to baseboard heat< YES provided it is Cast Iron and you have enough Pitch for the condensate return -
can we turn it down when not home and back up when home Lowering the thermostat to safe levels YES shutting off VALVES NO as this will trap condensate and cause hammering and possible piping failures –
what’s the hissing<< Hissing is the AIR Vents doing their job properly You cant have steam and air in the same space and expect to get heat. As the cold air is allowed to escape the steam takes its place.
Your Very Welcome Im sure