In order to predict the energy savings of a building before the actual changes are made, there are many software to choose from. Much software is costly and usually made for a specific type building. There are however several outstanding
free software that will satisfy your needs for practically
any building. Following are two of my favorites.
The most sophisticated software, eQUEST, is usually used for larger commercial buildings. It is a sophisticated, yet easy-to-use building energy analysis tool. With eQUEST, you’ll be able to provide professional-level results in an affordable level of effort.
eQUEST was designed to allow you to perform detailed analysis of today’s state-of-the-art building design technologies using today’s most sophisticated building energy use simulation techniques but without requiring extensive experience in the "art" of building performance modeling.
http://doe2.com/equest/ will give you all the information and software to be able to work with the most complex building.
For smaller and less complex buildings
HEED is simple to use by anybody.
HEED gives you the ability to draw in your own home, including placing windows and doors at their correct locations, and pick your construction type. Add different energy efficiency design options, and HEED automatically loads your local climate and utility rates and then calculates your energy consumption as reflected in a bar chart with dollars per year, kBTU per year or pounds of greenhouse gas CO2 as a percentage of your base-case homeUse the
updated version of HEED
