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Electric cast iron radiators

I've seen some talk of this here but nothing in the last few years.

I have my home gutted, so am able to run plumbing for water heated rads. But after speaking with the folks at eco rad - they are recommending the electric route. I'm interested. But I'd like to understand just what I will lose in efficiency, and if it will likely be more expensive to run cast iron rads off of electricity as opposed to water and boiler system.

The electric come with a 10 year warranty, and are obviously easier to maintain, and will save me purchasing a new boiler.

Would love some thoughts or experience. Thanks.


  • mattmia2
    mattmia2 Member Posts: 5,533
    They are more or less 100% efficient but electricity as a fuel costs several times what gas, propane, or oil costs in most areas. Electricity running various forms of heat pumps can be viable, but electric resistance heating usually costs far more that the alternatives over the long run unless you are in an area with a very mild winter or a source of very cheap electricity.
  • @mattmia2 That was my concern. Was hoping that I was missing something.
  • Jamie Hall
    Jamie Hall Member Posts: 18,953

    @mattmia2 That was my concern. Was hoping that I was missing something.

    You're not missing anything. They are a form of electric resistance heater, and so far as efficiency goes while it is quite true that they are nearly 100% efficient in using the electricity, the overall efficiency from the power plant depends on the power plant, and is usually around 40%. Or worse.

    If you can use a heat pump system, that is more efficient -- about as good as a mod/con boiler.

    If you use the resistance type, make sure that you have enough power coming to the property. You will need about 1 KW power for each 3500 BTUh of heat loss (1 KW is roughly 5 amperes on a 240 volt circuit, so if you house has a heating load of 70,000 BTUh -- typical -- you'd need a 100 ampere service just for the heating load, plus whatever your house load is -- typically another 100 to 200 amperes.

    And this isn't cheap, unless as noted you live somewhere where the power is really cheap.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Zman
    Zman Member Posts: 7,330
    What are your energy rates?
    This will help you compare.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • @zman having trouble doing the calc here. NS shows 18.76 per GJ...Is that equal to a therm ?
  • Zman
    Zman Member Posts: 7,330
    It looks like you will need to convert GigaJoules to Therms
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • GroundUp
    GroundUp Member Posts: 1,406
    If the alternative is NG, the operating costs of the electric will kill your wallet. In my neck of the woods, electric costs about 3.5x more than NG per BTU and approximately 2x what LP costs. Smaller loads, electric makes financial sense. I do a LOT of electric boilers running radiant floors around here for smaller buildings because the overall cost over a 20yr period is usually less than an LP system would be. Monthly costs are higher, but the upfront costs are around half and annual maintenance is almost nonexistent. With NG though, it wins every time with my local rates
  • jumper
    jumper Member Posts: 1,843
    Consider ceiling height electric radiant. You have thermostats for each room. So you do not overheat unoccupied rooms. No floor space is used up. In rooms occupied most of the time consider two thermostats. One panel radiates constantly while another kicks in only when you need it. It's comfort you want as opposed to therms. With high temperature radiation we can be comfortable at lower air temperatures.