Aaron Fude wrote:

I'm interested in buying one of these radiators, but I am having a
hard time believing the BTU ratings on these units. Is the 12,000
BTU's really possible in a 3'x3' radiator? I have a Runtal radiator
that is larger and it is only 2,000 BTU's. What do you think?

http://www.radiatorshowroom.co.uk/yo...-radiator.html

A watts to BTU conversion is pretty straightforward:
http://www.heatershop.com/btu_calculator.htm

The size does not matter.

R