In an earlier contribution to this discussion,
The Medway Handyman wrote:

Looking to put a rad in a new conservatory which is 3m x 3m ceiling
height about 2.4m. Three outside walls.

One wall is double skin brick block with insulation, two walls are
double glazed floor to ceiling. Ceiling is transparent plastic -
apparently with a high insulation factor (but its not the triple wall
stuff - its smooth). Floor is chipboard - don't know whats underneath.

Tried this site http://www.radcalcs.com/ which reckons about 6,000
btu's - but it doesn't have a pull down option for 'conservatory'.

Assuming this is right, its gonna need a 900 long x 620 high double
or there abouts.

Does this sound about right? I'd prefer to err on the side of
caution & fit a TRV.

TIA

I haven't seen the calculations - but I would be very dubious about the
result. Bearing in mind that 6000 BTU/Hr is somewhat less than 2kW, I doubt
whether that's enough[1]. I assume this is for a customer, 'cos if it was
yours, you'd know what was under the floor? Can you recover the cost of
doing the calcs, as well as of supplying and fitting the rad? If so, I'd try
to get hold of a better heatloss program (such as those available from Barlo
or Myson)[2] which allow you to specify U-values and other factors, and
which provide a breakdown of the calc rather than a single result.

[1] You could try putting a couple of 1kW oil-filled radiators in there on a
cold day to see how 'toasty' they make it.

[2] You can download the Barlo program from
http://www.barlo.co.uk/downloads_heatloss.php and, if you speak nicely to
Andy Hall, he'll email you a copy of the Myson program
--
Cheers,
Roger
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