The second law of thermodynamics puts the first law into context and establishes entropy as a concept. We can simply define entropy as a state of disorder that can only increase or remain the same in natural processes. Processes in which entropy remains the same are reversible, but ones that result in an entropy […]

DISCLAIMER: HVAC School is NOT an official OSHA safety training resource! Although we provide safety tips in good faith, our website is not a substitute for safety training from an authorized OSHA training source. Many things may deter people from working in the HVAC industry. Perhaps surprisingly, exposure to heights could be the deal-breaker. (Not […]

Probably the most popular measurement method for indirect airflow readings is total external static pressure (TESP). A dual-port manometer or two Bluetooth single-port manometers are essential to the HVAC technician toolbag. Here’s a quick review of TESP, why it’s important, and how to make the measurements. TESP is a pressure reading of the “balloon” pressure […]