In the current paper we quantified and evaluated the energy saving potential in air conditioners and chiller systems. We also showed how to reduce the cost of air conditioners and chiller systems in existing facilities on the basis of payback periods. Among the measures investigated were: 1) installing higher efficiency air conditioners, 2) installing higher efficiency chillers, 3) duty cycling air conditioning units, and 4) utilizing existing economizers on air conditioning units. For each method, examples were provided from Arizona, USA. In these examples, the amount of saved energy, the financial evaluation of this energy, and the investment cost and pay back periods were calculated.