Watts to BTU (IT) per hour conversion calculator above calculates how many BTU (IT) per hour are in 'X' watts (where 'X' is the number of watts to convert to BTU (IT) per hour). In order to convert a value from watts to BTU (IT) per hour (from W to BTU/h) type the number of W to be converted to BTU/h and then click on the 'convert' button.