Sometimes it’s hard to keep all the acronyms in the HVAC (there’s one right there!) world straight. There’s BTU, MERV, IAQ, BTUH, AFUE, ECM, HEPA, RH, and dozens more. So what’s this SEER rating all about? Well, SEER stands for Seasonal Energy Efficiency Ratio and it’s the standard measurement of efficiency for air conditioning systems. Here’s more about SEER, how it works, and how it came to be today’s standard.