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Replacement for old cast iron radiators

Hey all,

Found this forum while doing some research. A lot of info here and I'm sure that I already know the answer to this but figured it doesn't hurt to ask. I have a couple of jobs in which the house froze up and most if not all of the cast iron radiators froze and split. Both customers would like to replace the radiators with something a little more modern. Is there anything out there that can replace the radiators without taking up 4 times the wall space? These are 100 year old homes in Northern NY. Just to throw it out there - it doesn't necessarily need to be a hot water system. Since the homes totally froze up, a completely new heating system is not completely out of the question. Of course, running new piping, ductwork, or wiring would be very labor intensive and would need to be offset by cost of materials if any other route were to be taken.

Thanks in advance for any advice -
Regards, Tom


  • flat_twin
    flat_twin Member Posts: 351
    What a shame to lose a house full of cast iron radiators. How many? Have you looked into panel radiators? If one of them decides to go to forced air maybe you'll have enough donor radiators for the other place.
  • The Steam Whisperer
    The Steam Whisperer Member Posts: 1,218
    I'd start with a set of room by room heat load calcs. so you know what size rads are needed. Most existing hot water rads post 1905 or so are way bigger than needed to heat a house at 180F water.

    I'm converting from hot water to mini-tube variant steam vapor system, so my rad sizes are much smaller. AS it all works out, I end up with rads about the size of hot water rads at 180F, since that is about the temperature the steam system will work at. I eliminate the freezing issues and most need for electricity.
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • Big Ed_4
    Big Ed_4 Member Posts: 2,818
    Look into panel radiators

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  • Thackett1981
    Thackett1981 Member Posts: 2
    Thanks for the responses guys.

    I have seen the panel radiators suggested. Is the BTU output comparable per ft to the old cast iron ones?

    Twin: great idea, but the 2 homes have different radiators. One is the plain old standard ones. The other house has the decorative ones with the flowers or whatever.

    Whisperer: What is the mini tube steam all about? I have never thought about steam and the fact that it won't freeze like hot water. Its funny because I own a large building that has a steam heating system.

    I am thinking that there is no other option for my one customer that is worried about another freezeup. Hot air would be crazy expensive and electric would be nearly impossible with the load required.

  • hot_rod
    hot_rod Member Posts: 22,341
    Panel rads with individual TRV controls piped with a pex home run system.

    There are thousands of panel radiator type emitters available in Europe, many have US or Canadian importers.

    Blend in some radiant floors in bath and sitting areas.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • mattmia2
    mattmia2 Member Posts: 9,837
    If there is some real reason the system may be allowed to freeze again you can put a little bit of glycol hydronic system antifreeze in the system to keep it from bursting if it freezes but that is harsh on everything so unless there is a real reason it will happen again and you can't avoid it freezing some other way then use glycol.
  • mattmia2
    mattmia2 Member Posts: 9,837
    Oh, and as far as size, you need to do a heat loss calculation on the building to figure out how to size the new radiators. There is a good chance the old ones were oversized anyhow.