Lusec to BTU (IT) per second conversion calculator above calculates how many BTU (IT) per second are in 'X' lusec (where 'X' is the number of lusec to convert to BTU (IT) per second). In order to convert a value from lusec to BTU (IT) per second (from lusec to BTU/s) simply type the number of lusec to be converted to BTU/s and then click on the 'convert' button.