The two systems seem to not cool or heat the house efficiently. They indicators are the fuel cost is really high and the house is very difficult to heat or cool The second floor unit works better than the first by a little bit. Looking into this there is very little air flow from the registers on the first floor. After crawling in the craw space where the flexible duct is run. While the system was running I disconnected one of the 9" trunks from the main feed box feed from the attic. Air is coming from the attic unit. I am wondering how to increase the air flow out of the register. Do I add a blowers in the craw space on each of the trunks feeding the first floor vents to increase the air flow and pull the heat from the attic unit.

The house is ~2000 square foot house, two story wood/siding structure. A split system with both units in the attic. 1st floor unit is Gas furnace with A coil(Heat pump), 2nd floor unit is heat pump with electric heat backup. The two systems were installed when the house was built in early 2003. The duct work is flexible duct work with junction

Is this a recent development, or has it always been this way? Flex-duct is easy to install & inexpensive, but creates a lot of friction/resistance to airflow. I avoid using it whenever possible for that reason. You may look into increasing the blower speed, if higher speeds are available. Don't go overboard, though, or poor humidity control in cooling may result.