ComfortAir HVAC software is designed to be used by engineers, architects, contractors and energy auditors to calculate and analyse heating and air conditioning loads in commercial buildings. Input and output units can be set independently to English or Metric units. The program contains weather and other necessary data for 1,989 cities and localities in 163 countries, thus making it applicable for virtually any location in the world. Program output includes tables and graphs of cooling loads (load profiles) for all hours of the day and for all months. It also provides summary reports for peak conditions and a host of other useful information, such as reports and graphs of glass shading, from external shading devices like fins and overhangs. An example of how the hourly load tables can be useful, is in the design of thermal storage air conditioning systems, where ton-hour (kilowatt-hour) calculations have to be made in order to size the storage systems. The program is very user-friendly and it provides several useful wizards to make processes like data entry and U-value calculation easy to carry out and less prone to error and ommissions. Context sensitive Help illustrated by diagrams where appropriate, is provided at the click of a button. The program was developed as a multiple document interface (MDI), allowing the user to open and work on several projects simultaneously.