A commonly taught method for measuring airflow is the temperature rise method, where you use a heat source that produces a set number of BTU/h, such as heat strips. Then, using the sensible heat air equation, you can “easily” calculate the CFM being produced by the equipment. Let's use this specific example to illustrate the […]

That picture above is a WWII poster reminding soldiers of informed self-interest, which is something we ought to consider when making decisions. We live in a world where we often make decisions quickly and expect to see quick results. That works whenever I buy from Amazon. I order a new belt, and it shows up […]

I walked into my first real job interview in the HVAC trade. The manager was a guy named Ernie, and he walked me out to the warehouse. Quick warning: guys named Ernie are tough. Don't mess with a dude named Ernie. He walked up to a box, snatched a pen out of his shirt pocket, […]

Dick Wirz, author of Commercial Refrigeration for Air Conditioning Technicians, talks about making the switch from A/C to refrigeration. Dick Wirz is an advocate for using rules of thumb, which is a controversial position. However, rules of thumb are an excellent way for A/C techs to dip their toes into the refrigeration world. Rules of […]