are there real differences between radiatior heat output ?

[reellifetv]

About to replace several rads on my gas central heating. A plumber had recommended Heatline, but the local plumbers merchant is pushing Barlo.

The Barlos have a similar appearance - compact double panel double convectors - and will work out rather cheaper too. However the stated heat output appears to be about 10% higher on the Heatlines.

Is there likely to be a real difference, or is it just a matter of the conditions under which the measurements were made (ie water and room temeperatures).

Many thanks,

chris

[Doctor Evil]

Barlo are good. Some rads do give more heat per squ. ft than others, by more fins on the rear, etc.

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[John Rumm]

Yes ;-)

Or less concisely, there may well be a smallish actual difference in output between brands when comparing like with like, although these will obviously still be within bounds governed by the laws of physics. There does not seem to be any standard set of assumptions (about flow temperature etc) made by rad manufacturers however, so that often accounts for much of the quoted differences.

Best bet would be to do the heat loss calcs and work out what is required, then oversize a little to allow for future changes (like reduction in flow temp).

[Set Square]

Radiators of a similar size and design made by different manufacturers will have very similar *real* outputs. But their figures may not be based on the same delta-T (the difference between rad and room temperature).

Each manufacturer should state the delta-T on which their figures are based. Conversion tables are available for working out the output at a different delta-T. They sometimes appear on manufacturers' spec sheets. I'm looking at one at the moment, with figures based on a delta-T of 60 decC. There is a table of factors to multiply by for different delta-Ts. To quote a few:

45: 0.700 50: 0.798 55: 0.898 60: 1.000 56: 1.104 etc.

[Mike]

Most definitely. Compare your brands with Stelrad Elite and if they come off worse order these instead as they are often the same price anyway.