It is a good idea to have the rear just slightly lower than the front edge to prevent water (condensate) from dripping inside.
However, most window a/c's use the heat from the unit along with the fan to dispel the water out the back and/or sides of the a/c outside the house.
If you do have the a/c tilted just back a bit, it should prevent any surprises and puddles on the floor, if you leave the a/c running when you're not home, etc.
Answers & Comments
It is a good idea to have the rear just slightly lower than the front edge to prevent water (condensate) from dripping inside.
However, most window a/c's use the heat from the unit along with the fan to dispel the water out the back and/or sides of the a/c outside the house.
If you do have the a/c tilted just back a bit, it should prevent any surprises and puddles on the floor, if you leave the a/c running when you're not home, etc.
Hope this helps and best regards!
Yes you want the outside to be lower then the inside so the water will run outside and not inside. just a slight amount will do1/8 of a inch will do.