What Does “15x20x2” Mean on an Air Filter? (Nominal vs Actual Size Explained)
If you’ve ever replaced an HVAC filter labeled “15x20x2” and noticed it didn’t measure exactly 15 by 20 inches, you’ve experienced one of the most common—and costly—air filter misunderstandings we see at ProHVACDigest.com. After reviewing thousands of homeowner questions and technician notes, we’ve found that confusion around nominal vs actual filter size is a leading … Read more