Check the model of your air conditioner stamped on the equipment. Make a note of the model number and the serial number of your air conditioner.
Look over the unit closely and see if the BTU information is stamped or tagged somewhere on the Whirlpool air conditioner.
Check the manual of your air conditioner. The manual of your whirlpool air conditioner will give the number of BTUs in the model of your Whirlpool air conditioner.
Log on to the Whirlpool website if you do not have a manual. Check the product section under room air conditioners. You will find the BTU details of your model of air conditioner on the website. You can also email Whirlpool by filling the email form including the model number and serial number of your air conditioner.