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Question: cast iron radiators & paint

todd_14 Member Posts: 18
Does cracked and peeling paint on a radiator significantly reduce heat output?? 

Does bare cast iron give off heat better than painted surface? 

It is a not a metallic color.  

Thanks for you input 


  • Jamie Hall
    Jamie Hall Member Posts: 23,554
    No, it won't change the output significantly
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Member Posts: 22,382
    I would say any insulative coating will slow the heat emission. Bare cast should have a slight advantage, to a painted surface. Older radiators can often have many layers of paint, each layer adding some resistance.

    If so the cracks give you some exposed metal :).
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream