Cast iron vs modern radiators

[geraldthehamster]

I have several reclaimed cast iron radiators installed in my house, 1950s school radiator style with single wide columns. Each around 900 x 700.

Can anyone tell me if modern double convector radiators would be more effective? I understand that cast iron takes longer to heat up and cool down, and that the boiler might have to work harder to heat the greater amount of water in a cast iron radiator. But I don't know how that translates into how warm my house will feel.

I'm considering replacing the cast iron but am uncertain whether it's worth it for any difference it would make.

Thanks
Richard

 

[John D v2.0]

Modern radiators have a better surface area mainly due to the fins. As to whether it's worth replacing them, it depends on a lot of variables. Do you like the style of the existing? How much do you feel the cold?
Also consider supplementing them with another smaller radiator.

 

[stem]

The output of a radiator is usually given in btu's (British Thermal Units) measured at an operating temperature usually of 60 degrees C.

The old cast iron radiators vary in their design with different numbers of columns and segments. If I had to guess, I would expect yours to be somewhere in the region of 2000 to 4000 btu's. They are still available to buy, and if you search on line and find a model that corresponds closely to yours in size and design, then you should be able to get an indicative btu figure for it.

Once you have the btu figure you can compare it with the figures for modern traditional radiators.

The btu figure relates to the heat emitted by the radiator. The boiler simply puts back the heat that has been emitted into the room, so the costs of running a 3000 btu cast iron radiator would be the same as a 3000 btu modern one. If the cast iron radiator has a delay warming up, (compared to a more modern one) the heat would be recovered in the delay in it cooling down.

 

[geraldthehamster]

Modern radiators have a better surface area due to the fins. As to whether it's worth replacing them, it depends on a lot of variables. Do you like the style of the existing? How much do you feel the cold?
Also consider supplementing them with another smaller radiator.

Thanks. I like the style, I installed them. However, I have two in quite a large room, and it takes a long time to get warm in the morning. I'm not even convinced that they heat the room effectively (I use a wood burning stove as well so the point is moot). I have modern radiators in other rooms, and it's my subjective perception that they are more effective. I wondered if there was objective data in terms of BTUs and so on.

 

[Lower]

Cast iron radiators will not be as efficient as modern multi panel radiators.

Modern radiators have much greater surface area and are made from thin steel which is what makes them more efficient by transferring the heat from the water inside them to the air inside the house through convection and radiation.

Cast iron radiators will require more heat to heat up the greater mass of cast iron in the first place and then won't transfer the heat from the water as effectively as a modern radiator. They will take longer to heat up and cool down more slowly.

The only reason to install cast iron radiators is for appearance. They will be less efficient at heating your house.

 

[stem]

I wondered if there was objective data in terms of BTUs and so on.

Our previous messages crossed in the ether

 

[geraldthehamster]

Our previous messages crossed in the ether

They did.