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Calcimator

HVAC Filtration Efficiency Calculator

MERV rating selection from particle size targets.

Inputs

Results

Filtration efficiency (%)

85

Pressure drop (in. w.g.)0.27
Face velocity (fpm)300
Fan power increase (W)14.6
Annual energy cost ($)$15.31
E1: 0.3–1.0 µm (%)50
E2: 1.0–3.0 µm (%)85
E3: 3.0–10.0 µm (%)90
How to Use This Calculator
  1. Enter MERV rating (1–16), Target particle size (µm), and System airflow (CFM).
  2. Set Filter face area (ft²).
  3. Review the Filtration efficiency (%) result.
  4. Use Pressure drop (in. w.g.) and Face velocity (fpm) to inform your decision.
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