How to count NAS BTU

Generally Thecus NAS 1W about 4.265BTU/hr (Redundant power 4.2652BTU/hr ), thus we could converter from watt from power supply, also we could found the power supply specification from NAS specification: http://www.thecus.com -> Linux NAS -> and choose you model.

If you can't found you NAS mode please choose from www.thecus.com -> Linux NAS -> Archive or
http://www.thecus.com/product_archive.php?ARCHIVE=Y&PROD_TYPE_ID=1

EX1: N8900 specification about redundant power supply 500W or more, and should less than 700W depend on shipment condition, thus N8900 BTU will be:
500x4.2652=2132.6BTU/hr
700x4.2652=2985.64BTU/hr

EX2:
1U4600-S single power is 200W = 200x4.265=853BTU/hr.
1U4600-R redundant power is 250W = 200x4.2652=1066.3BTU/hr.