The AET App is intended to give the home owner, engineer, architect, or architectural student a quick estimate of how much energy a specific building will consume annually, along with the annual utility bill. The building’s energy efficiency is shown as an EUI (Energy Use Intensity) in terms of Btus/sq.ft. per year. For comparison purposes, the user is also shown a range of expected EUIs that are typical for the building type being evaluated. The program is full of various defaults that are based on an internationally recognized building energy efficiency standard. By running the software without modifying the thermal parameters, the user can see what the top energy efficiency could be for a building of this type, climate location, and fuel types. Then, the user can modify the thermal characteristics to match his/her real building and then make efficiency comparisons. Included in the tabulated results are the peak HVAC loads (i.e., the heater and A.C. sizes). This indicates what size equipment should be installed in the building. These input parameters are done simply by tapping the eight icons on the opening screen in the order suggested, and then tapping specific sub-parameters under each item. To make it simple for the user, most all of the building parameters are automatically selected by the program after the user selects building type and climate region. The parameters are set as defaults for building type and climate location based on a well-known energy standard prevalent in the U.S.A. The energy standard on which the defaults are based is ASHRAE (American Society of Heating, Refrigerating, and Air-conditioning Engineers) Standards 90.1-2010, 90.1-2013 and 189.1 for green building design. While using the App, the user is shown all these defaulted parameters and is given the opportunity to make any changes that are desired. Only certain screens will allow for user changes, while others are for information display only. Several of the screens, including the overall energy summary page, can be saved to the Pictures directory under the user’s name on his/her computer. These are ASCII files that can be printed out later.