1. Calculate the volume of the room you want to heat by multiplying the length times the width times the height. Those dimensions should be in feet, and the resulting volume will
http://www.ehow.com/how_5583529_calculatesizerad...

Calculating radiator BTU's. Step 1  Find the volume of the room in cubic metres: Calculate length x width x height. Step 2  Adjust according to room type: Lounges and dining rooms
http://wiki.answers.com/Q/How_do_i_calculate_the_s...

Radiators are different sizes depending on the amount of heat you need. A good rule of thumb is that 45 BTUs of heat per square foot of floor space in a room with and 8' ceiling will
http://answers.yahoo.com/question/index?qid=200802...

Did the calcs online using their diy section. What sort of size are we talking? I know you can get single or double rads?
http://www.diynot.com/forums/viewtopic.php?t=48143
