They need to be replaced as the metal coils (?) are bent and very old. We were told that new ones would be throw out alot more heat.
I don't buy that. Add some baseboards to throw out more heat but leave the old ones alone unless they are too beat up to look at. If you take the old ones out I'll buy them from you and use them in a rental. There is nothing wrong with them. HS.
Copper pipe with aluminum fins. Pretty simple. The copper last forever and the fins just get yucked up with stuff and bent but you can't hurt them. I own two hot water systems and i don't think they can compare to forced air for cost but I like the heat better.