What is the difference between the 36", 48", and 60" models?

The primary difference is the unit width and airflow capacity. The AC-1036-12-BK provides up to 1,177 CFM, the AC-1048-12-BK provides up to 1,648 CFM, and the AC-1060-12-BK provides up to 2,119 CFM on high speed. Choose the model that best matches the width of your doorway.