Central heating radiator

[andicole0]

How do you work out what size to replace a radiator with. I have a single rad with fins on the back that is 800mm wide and 900mm tall. I want a rad that is taller but only 400mm wide, is it simply a matter of the same surface area?
Andi.

 

[SimonR]

Use an online calculator like this one.

 

[Jez]

This need not be complicated, you could just look at the BTU rating of a new same style radiator in your existing size, and then find one with a similar BTU in your desired shape/size. It isnt an exact science.

 

[samurl]

Are you going for design over function? There should be calculations available online for square footage vs rad requirements to work efficiently.

 

[craigmmmm]

Make sure your boiler can handle a bigger rad.

 

[Iron-man]

you cannot just go of the size of you existing rad as was said above. If you measure the size of the room the rad is for then input into a calculator online it will tell you how many BTUs you need for that room size, then you can look at rads accordingly. I have just changed a rather large old one in my house and I could have gone to a third of the size to heat the same with a new radiator as there more efficient.

 

[robj20]

Don't forget radiators are rated at a Delta 50c which isn't really efficient for a modern condensing boiler.
Bigger radiator the better there are no functional downsides to getting the biggest radiator that will fit in the room.

Delta 50c is 80c flow, 60c return and 20c room temp.
Therefore 70c radiator temp. 70-20=50c.

Condensing boilers prefer return to be less than 55c. So you can see why delta 50 is a bit rubbish.

My house is based around delta 30.

60 flow, 40 return, 50 rad temp. It often far exceeds this though, very often the flow temp will be 30c or less.