I have an upflow forced air furnace to which I added a 3-ton air conditioner. The uncased A-coil sits in the plenum above the furnace. I have a question regarding airflow. Approximately 5 ½ feet above the top of the furnace is a square right angle to carry the air horizontally across the bottom of the first floor joists. Approximately 4 feet from that right angle is a second square right angle directing the air into the main duct for distribution throughout the house. My question relates to these right angles. Would it be beneficial to the airflow to change the second square right angle to a curved one? Would a curve not improve the flow? My concern stems from the fact I have 3 X 10 registers throughout the house, since originally there was no air conditioning. I have been told I should have 4 X 10 registers for the A/C. I know of no way I can make the change, therefore I?m looking to find any way I can to improve the airflow. If there is a way for me to change the registers, I?m prepared to do that. The unfinished basement portion is no problem, it?s the finished area of the house that is a concern. I?d appreciate any suggestions you might offer. Thanks.
Don