Net refrigeration effect (NRE) is the quantity of heat that each pound of the refrigerant absorbs in the refrigerated space to produce useful cooling. That’s a pretty vague definition. We know that it’s an amount of heat in processes that take place within the evaporator. Still, the phrase “useful cooling” seems rather broad. Even though […]

This article is an updated version of another HVAC School article on oversized equipment. This edition is a joint effort by Genry Garcia of Comfort Dynamics, Inc. and Kaleb Saleeby. Both of them are regular contributors to HVAC School, and we are grateful for their contributions. Thanks, guys! The symptoms and consequences of oversized heating […]

It's Friday at 6 PM. The schedule is clear, as far as you can tell. Other guys have been getting cleared right and left, so you call in standby. Five minutes pass. Ten minutes pass. You check in again, and sure as &%$#, there it is! You get sent across town to another call that […]