These articles describe the background assumptions used in assembling the different HVAC system setups within the product. Sefaira is constantly striving to work towards better inputs for our HVAC system designs. Objectives of Sefaira Systems: Sefaira Systems is designed to solve a specific HVAC design problem: To get good direction on the impact of System plus Envelope strategies at the earlier stages of design without having to invest very much time or effort in a fully-customised space load and energy model. It is expected that Sefaira Systems will be most useful at the stage of design where the HVAC system is being selected (usually Schematic Design, sometimes early Design Development, sometimes late in Concept Design). For all but the simplest of projects, it is not likely that Sefaira Systems will be applicable for code compliance submittals and detailed load calculations in the latter stages of design.