This is a fully self-contained, premium single-page web application. It uses Tailwind CSS for layout and design, Lucide icons for visual feedback, and pure JavaScript for real-time reactivity, all compliant with sandboxed iframe environments. ```html Free HVAC Air Filter MERV Rating & Pressure Drop Calculator

Air Filter Pressure Drop Calculator

Optimize HVAC efficiency and system airflow resistance.

Input Parameters

Estimated Results

Pressure Drop (inches w.c.)

0.22
Marginal

The calculated pressure drop is within an acceptable range for residential systems. Ensure regular maintenance to avoid performance loss.

Understanding MERV Ratings

MERV 1-4: Captures large particles like dust mites and carpet fibers. Minimal air resistance.

MERV 8: Good for residential use; catches mold spores and pollen. Standard balance of filtration and airflow.

MERV 11-13: Captures bacteria and fine particles. Highly effective but requires checking system capacity for increased static pressure.

MERV 16+: Clinical and surgical grade. Typically too restrictive for standard residential HVAC blowers without modification.

Disclaimer: This tool provides estimation models based on standard industry coefficients. Actual pressure drop varies based on filter age (loaded vs clean), pleat count, and specific ductwork design. Always verify with a certified HVAC technician.