Energy Suite: Energy Cost Calculator for Buildings is an energy cost calculator that allows you to assess the energy demand for a simple building and calculate annual energy costs. The calculation worksheets also help you determine the sizes of some HVAC system elements. All the modules are linked together and are updated as you provide the input in the colored input cells. For example, you can update the heating and cooling loads and then go to the annual costs module to see the updated annual costs. Only ‘0’ and positive numbers, including decimal numbers, are valid inputs for the input cells with the exception of negative temperatures. Nonsensical and inappropriate input will result in the calculation of nonsensical results. The calculation worksheets use Imperial units that are common in the U.S.A. Input parameters are measured from the building, or obtained from standard sources such as ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers), or on the Internet, such as http://www.degreedays.net for heating and cooling degree days based on geographic location. All the calculation worksheets are copyrighted by Dr. Ganapathy Mahalingam of Digital Design Solutions LLC of Fargo, North Dakota. (© Ganapathy Mahalingam, 2015) This app provides the best interface on tablets 7″, 8″, 10″ and above in screen size.