The Rooftop Unit Comparison Calculator (RTUCC) is a free online tool developed by the U.S. Department of Energy.
The RTUCC simulates the energy usage of both a high efficiency and a standard efficiency air conditioner. It then compares their energy and economic performance.
Put in details, such as your building type, location, temperature and humidity settings, as well as unit capacity and efficiency. You'll get estimates for simple payback, net present value, life cycle cost analysis and other financial performance measures.