Howto calculate radiator size for room

[Plumbagain.]

Some plumbers can judge the size exactly without any calcs.

 

[jonnyswamp]

What makes you think he wants to fit a new rad? Perhaps the existing one is a 5ft double.
He wants to check whether his existing one is up to the job, and presumably take it from there.

If it's taking 5 hrs to heat a room, it's obviously not

 

[jonnyswamp]

Some plumbers can judge the size exactly without any calcs.

That's exactly how we used to do it
Always worked OK but not scientific enough apparently

 

[doitmyself]

Of course it's based on kW/sq.m. The manufacturer may not state it explicitly, but there's no other way of doing it.

If kW/sq.m. is such an important parameter when sizing radiators, why don't the manufacturers provide this information?

If I need 1.75kW to heat a room and the space available is 2 metres long, I can easily select a suitable radiator from a catalogue without needing to know the kW/sq.m.

 

[fixitflav]

If kW/sq.m. is such an important parameter when sizing radiators, why don't the manufacturers provide this information?

If I need 1.75kW to heat a room and the space available is 2 metres long, I can easily select a suitable radiator from a catalogue without needing to know the kW/sq.m.

Why should they? Manufacturers don't usually release technical information. But they must have it as there's no other way of sizing a rad, as I've said.
I was just trying to help the OP to deal with his problem. I've explained and answered your comments several times but you don't appear to understand.

Of course there are other approaches. ​

I unsubscribe from this discussion.

 

[Last Plumber]

Did the OP switch off?

 

[jtsplumbing]

Would help if he told us the size of his room and size of currant rad, baffles me why some people get so involved with complicated formulas and calculations just for a radiator, chaps who have been doing this long enough will know by just looking at the room, if rad is slightly oversized so what, there is a proven way to get over this , its called turning down the valve, and most people can do this without calling a engineer, things are to over complicated just no need for half of this BS.

 

[Last Plumber]

Would help if he told us the size of his room and size of currant rad, baffles me why some people get so involved with complicated formulas and calculations just for a radiator, chaps who have been doing this long enough will know by just looking at the room, if rad is slightly oversized so what, there is a proven way to get over this , its called turning down the valve, and most people can do this without calling a engineer, things are to over complicated just no need for half of this BS.

If he gave the sizes and info I asked for in an earlier post, I would work it out and tell him what output I would recommend. I thought it might be a help.

 

[Last Plumber]

things are to over complicated just no need

I would tend to agree with that.

It is one of those long winded calculations which is very methodical and precise. The result however, can still be inaccurate due to all the other factors involved, which are seldom taken into account or cannot be measured.

 

[SimonG]

Better looking at it than for it.