This study employs the developed simulation software for the energy use of the high-tech fabrication plant (hereafter referred as a fab) to examine six energy-saving approaches for the make-up air unit (MAU) of a TFT-LCD (thin-film transistor liquid-crystal display) fab. The studied approaches include: (1) Approach 1: adjust the set point of dry bulb temperature and relative humidity in the cleanroom; (2) Approach 2: lower the flow rate of supply air volume in the MAU; (3) Approach 3: use a draw-through type instead of push through type MAU; (4) Approach 4: combine the two stage cooling coils in MAU to a single stage coil; (5) Approach 5: reduce the original MAU exit temperature from 16.5 °C to 14.5 °C; and (6) Approach 6: avoid an excessive increase in pressure drop over the filter by replacing the HEPA filter more frequently. The simulated results are further compared to the measured data of the studied TFT-LCD fab in Taiwan. The simulated results showed that Approach 1 exhibits more significant influence on annual power consumption than the other approaches. The advantage/disadvantage of each approach is elaborated. The impact of the six approaches on the annual power consumption of the fab is also discussed.