Our dryer exhaust consists of 6 feet of flexible hose into 16 ft of the 4" green pvc/sewer line. The last foot before the vent is insulated on the outside with duct insulation. There is one elbow where the flexible hose attaches to the PVC. The clothes take forever to dry and when I checked the line it has standing water in it (maybe a 1/4 inch). The pvc pipe is level, and exits through a brick wall, so I cannot really change the slope of the pipe. I also cannot change the venting. It must go down through the flow and out through the basement. I am worried that the distance from the dryer to the outside may be too far. Is there a fix for this problem? Do I need a new dryer with a stronger blower? Do I need to insulate the pvc pipe?

I would appreciate any advice. Thanks in advance.