https://communities.bentley.com/products/building/performance/f/hevacomp-forum/128117/air-changes-per-hour-achHi, I would like to know what should be the value of Air Changes per hour that has to be mention in the room data in winter and summer as per by the CIBSE standards. Regards, Junaid Khanen-USTelligent Community 12https://communities.bentley.com/thread/390538?ContentTypeID=1Mon, 07 Nov 2016 14:07:20 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:7152710b-b189-42a4-93d6-a934370e07d3Duncan BrownHi Junaid - The air changes figure should be defined by yourself - the input fields represents the required air changes per hour for your design. As such we can&#39;t really offer you specific figures.<br /> <br /> Regards,<div style="clear:both;"></div>