The Design Point Is Not Reality

Equipment runs most hours at part load, not at the rated condition. Sizing only at the peak point overstates savings.

How to Size for Real Use

• Build a load profile across the year (bin method or hourly)
• Compute recovered energy at each load step, not just the peak
• Weight by annual operating hours to get true savings

Effectiveness at Part Load

Effectiveness rises as face velocity falls, so part-load operation is often more effective than design. The fan energy, however, falls too - net the two for a realistic payback.

Verify

Ask for the effectiveness curve, then integrate it over your actual profile instead of quoting a single percentage.