Side air conditioner problems

I have an older model side air conditioner. It is very inefficient. I know the newer units have a roof mount air conditioner that are more efficient. However, my unit is too old to support installing one. Anyway, does anyone know how to make it more efficient? I can buy a new air conditioner, but I think the design of the return air hitting the bathroom and returning is messing up the thermostat. Advice please????

[Wavery]

I would suggest reading through this thread:
http://trailmanorowners.com/forum/sh...rip+pan&page=2

It not only discusses the installation of a new AC, it discusses a few ways to make it more efficient.