ExTLA Lite, a simple Excel-based calculation tool for energy consumption of residential building
A calculation tool for a single room. Insulation, types of windows, orientation, etc. can be studied.
Manual for ExTLA Lite 1.4.1 (PDF)
ExTLA Core, a accurate calculation tool for annual heat load
* Right click on the link and save the file.
* It has been confirmed this tool work with Excel 2007 and 2010 on MS Windows, not confirmed on MacOS.