[Image:Air handling unit.JPG|thumb|270px|An air handling unit; air flow is from the right to left in this case. Some AHU components shown are
1 – Supply duct
2 – Fan compartment
3 – Vibration isolator ('flex joint')
4 – Heating and/or cooling coil
5 – Filter compartment
6 – Mixed (recirculated + outside) air duct]]