Did the contractor test the airflow to see how mush air it was getting? One thing that I have seen happen on change outs is that the supply plenum gets reconfigured a little different and some trunk lines end up not getting as much air as they used to and vise versa. Generally when I find a room that is not getting enough air I start looking for a room that is getting too much air.
Chip where are the returns? How many and in what rooms?
It is very difficult to heat or cool a room that does not have a return in it. Here returns are in all rooms except Kitchens, Bathrooms and Laundry Rooms. In my home, I have High and Low Louvered Returns. That way for the Winter, on Labor Day, I close the top and open the bottom. Then in the Spring on Memorial Day, I open the top and close the bottom. I can also adjust the flow in the rooms by how much each return is opened. For example on the East side of the home, the returns are reduced for the Summer and on the West side, wide open. This way I do not have to adjust the supply side. I call it “ X’s Return Air Balancing!”
P.S. Booster Fans DO NOT increase Flow!
The quality of my performance, sometimes depends on the quality of my audience.
Imitation (Plagiarism) is the best compliment one can get -- "Open A Window"
To improve Indoor Air Quality: Control Indoor Air QUANTITY = "I.A.Q.Q."
There are returns in the wall in the two front bedrooms. The booster fan seems to have fixed the cooling problem. These rooms are staying at 75 and 76 now, and we had a couple of hot days last week. So makes me happy