Design may include freehand sketches using the floor plan(s) and basement plan, should consider the consumer’s needs, system efficiency and sustainability, and should maintain compliance with building codes. The designer must determine

• type of heating system
• type of cooling system
• size and location of trunk and branch lines and registers
• location of return air duct
• sizes and locations of vents
• location of thermostat. 

Process/Skill Questions:

• What are the pros and cons of heating a residence with the forced-air method vs. the hot-water method?
• Why is a return air vent and duct necessary for a forced-air system?
• How does a forced-air system compare to an electrical circuit?
• What effect does the insulation in the walls and roof have on the HVAC system?
• Where (in what rooms) should a return air duct not be located?
• How does one calculate heat loss for a house plan/design?