As many of us started in the industry, we learned quick rules to simplify complicated topics. One of these first rules is 12,000 Btus (British thermal units) per one ton of cooling capacity. It’s a rule that many in our industry accept, but is it always true? Could this rule get you in trouble if you don’t dig a little deeper? Let’s look at how equipment cooling capacity tables can answer these questions with the tons of information they contain.