Radiator Output research

bluetangle

Hi

Trying to work out whether or not it's worthwhile replacing my old gas central heating radiators with the latest versions.

Have the measurements of the radiators I might replace. Singles with fins on the back and another old single.

Just wondering is there anywhere I could find out what is the output of my old radiators and what increase I could expect from new replacement ones.

Any help would be much appreciated.

10-10-20

https://www.boards.ie/discussion/2058412122/radiator-output-research

Have a look at stelrad's website. The old units might be K1 types and K2's are the double-depth with fins in between.

Oversizing by a good margin and then dropping the flow temperature is always a good idea, especially if you have a condensing boiler.

Wearb

https://www.boards.ie/discussion/2058412122/radiator-output-research

Were the existing ones undersized in the first place, or what is your reason for wanting to change?

Lenar3556

https://www.boards.ie/discussion/2058412122/radiator-output-research

Bigger radiators = more heat = higher running costs.

There is little or no efficiency saving between radiators, so the initial rational as to why you are doing this is relevant.

10-10-20

https://www.boards.ie/discussion/comment/123500908#Comment_123500908

I can't agree. I'm running my boiler with a feed temperature of around 45 to 50C, so I needed to oversize the rads to achieve the same heat output.

Lenar3556

https://www.boards.ie/discussion/comment/123500978#Comment_123500978

And that’s fine, you have reduced the flow temp to compensate.

The point I am making is that sometimes people are changing radiators with a view to improve efficiency and there is no return on investment in doing so.

Sleeper12

The main difference (if any) in replacing the rads, is that old rads could be caked with sludge. Replacing the rads removes the sludge in the rads.

A proper power flush with chemicals will remove more sludge than replacing the rads.

I do believe modern rads might have been higher output but it's minute if at all.

With a clean heating system with mag nah clean, I don't believe you will notice any difference between old & new rads

10-10-20

https://www.boards.ie/discussion/comment/123501015#Comment_123501015

Oversizing rads increases the volume of water in the system and makes it less responsive, so more likely to overheat the space.

Sleeper12

https://www.boards.ie/discussion/comment/123501127#Comment_123501127

Doesn't that depend on the heating system. I thought Condensing boilers need over sized rads to run efficiently.

A heat pump system needs to oversize the rads even more because the running temperature is far lower than a gas /oil heating system as far as I understand

Wearb

Don't get hung up on "oversized" what we're really talking about is correctly sized rads for the flow temperature.

Saying oversized confuses the issue, especially for the non plumbing visitors here.