Are LOUDLY hissing radiators normal? What can be done about them?

I’ve never lived in an apartment that used radiators for heat before now. Like many places in Chicago, my apartment building is very old and uses them. I know that radiators make hissing noises, as steam is involved.

But the radiators in this apartment are loud - imagine a radio tuned to static with the volume maxed out. So loud that you cannot have a conversation when they’re running. So loud that they drown out the television or music. It’s really more of a roar.

What’s going on here? What can be done about this? Are they doing this because something needs to be done, like bleeding some air out of them or something? They have little silver valves on them that look pretty new - how are those involved?

I assume you have called the building manager by now. If you haven’t that’s the place to start.

Radiators that loud aren’t normal in my experience. I was the guy who ran the furnace in a movie theater pre-WWII and our radiators made a moderate hissing noise when the system pressure came up so as to put steam into them. And in the morning after they had been relatively cool during the night, there were occasionally some noises from the metal expanding from the heat, But nothing as you describe things.

Your radiators probably need bleeding: