Replace baseboard that use aluminum wiring

There are stickers on them somewhere. It was a requirement and they had to be visible after the baseboard heaters were installed - although they might have been painted over. In general, you'd replace the old heaters with new heaters of the same wattage. If you can't find stickers to tell you the wattage, an electrician can tell you what they are by measuring their amp draw at the service panel. In 1969, they're going to be 240-volts so you should replace them with new 240-volt units. I don't know why you want to replace the heaters, but if it has to do with efficiency, don't bother. New baseboard heater's aren't even a tiny bit more efficient than 1969 baseboard heaters. They're both 100% efficient - 100% of the electricity that they use is turned to heat.

source https://www.inspectorsjournal.com/topic/18921-replace-baseboard-that-use-aluminum-wiring/?do=findComment&comment=172721