I have questions regarding the ventilation for a possible whole house fan in our home. We live in the Coachella Valley in Southern California where temperatures regularly hit 115° to 120° in the summertime. Growing up in the Midwest, all of our homes had whole house fans and we want to add one in our home out here. We have an area in our home where a Quietcool brand fan will work, but I need to know if I can exhaust the fan into the sealed insulated truss space above our ceilings. We have 2 feet of space between the drywall and the flat roof deck that covers our entire 1700 sq.ft. house. The space is ventilated with enough wall vents to meet the manufactures requirement for the fan. But I need to know if the air will pass through the 16” of insulation in that truss space efficiently enough so I’m not creating back pressure in the fan.  I am a licensed general contractor out here, but I do not have enough knowledge of ventilation to blindly dive into this. I called my HVAC subcontractor and he doesn’t know because no one has ever asked him to install a whole house fan. So any help you all could provide would be greatly appreciated. Thanks!