Just jerking your chain mines free cannot teach on this board what it took me 40 years to learn. I must be a slow learner???
Just can not get away from Hvac did another IR scan today and the client complained about another room on the second story that was always cold and wanted me to scan the room. It took me no longer than it takes to enter the door to see the problem. Large bedroom on the NW corner of the home no wind breakers on the exterior and the supply duct was being fed with a six inch duct I could tell this by the size of the grill on the ceiling and confirmed by entering the attic.
The take off from the plenum was a 9 inch trunk and had 3 drops being supplied I could have spit more air than was being discharged from the register. This home had been added on to on both levels and the upstairs two added on rooms was being fed from an upstairs furnace and the supply for the addition was tapped into the top of the plenum with no balancing damper installed. The new addition was robbing all of the air from the remaining section of the home. This was accomplished by a Hvac contractor. Grab the money and go. And how many times have I heard on this board refer to a HVAC contractor.
The moral to this story is I wonder how many IR guys would have Scaned the room pointed out any deficiency noted with the camera and walked away???