Indo-Swiss Building Energy Efficiency Project (BEEP) is a cooperation project between the Ministry of Power, Government of India, and the Federal Department of Foreign Affairs of the Swiss Confederation. Started in 2011, the project's central focus is to help India mainstream Energy-Efficient and Thermally Comfortable (EETC) Building Design. BEEP works with building industry, policy makers, and building owners to catalyse adoption of EETC building design and technologies. India wants to avoid or reduce the use of air conditioning by improving natural ventilation at night, which requires numerical simulations to compute the flow around the buildings. However, the simulations of fluid flows are time consuming and are not used at the beginning of a project when the locations of the buildings are set. To improve the situation, a freely distributable environment based on the OpenFOAM toolbox has been developed providing two levels of resolution: an approximate level computing the flow in few minutes and a RANS level of simulation. The user inputs are limited to the geometry and the velocity direction and magnitude. The mesh and the numerical set up are automated. The accuracy of the two levels of resolution have been checked by computing test cases from the CEDVAL database.