Stupid question - radiator efficiency

[namechangedtoday15]

So, the BTU calculator says I need about 3700 BTU to heat a bedroom. I have found a couple of options - so (for instance) a 2 column vertical radiator (so very tall and slim) with a BTU output of about 4000, and a 3 column radiator (more traditional rectangular, about 1m x 60cm) also with a BTU output of 4000.

Will they both produce the same heat / warm the room equally? I know placement plays a part (i.e. under a window or not) but should I be judging simply of BTU output and then the rest is just a preference re style?

Thank you for any advice.

I'm no expert either but my guess would be that one has a higher wattage than the other or that one might be a single row of bars and the other a double row?

Thank you becks - I understand its probably to do with the depth - 3 columns as opposed to 2 say, but the BTUs and wattage are very similar. It was probably a question as to whether the surface area makes a difference?!

A low wide one will heat the room more evenly than a narrow tall one, even if the nominal output is the same.

Tall radiators are very good at heating ceilings.

Thank you PJ