ACH

ACH

1. Automatic Clearing House. A computer based system for exchange and settlement for electronic payments (cf EFT) between participating banks and financial institutions.

2. Automatic Cheque Handling, or US-spelling: Automatic Check Handling.

3. Air Changes per Hour. The number of times the volume of air in a given space (typically a room or a building) is changed every hour. It is used as a measure of ventilation.