Do baseboard heater loose efficiency if they are old?
Do I need to replace them if they are 30+ years old but still work?

HI Johnmickel...

What kind of baseboard are we talking about... cast iron or copper tubing/metal fin type? Do you have glycol in the system? That info. Would help here...

In terms of replacement, until you have your first issue/problem with the baseboard I wouldn't go messing with things... noy usually.

Why do you have this concern? Let me know more, OK?

Mark