Greetings:

I am in a first floor of a two floor appartment complex. All the room is directly under an isolated roof and my 4/5 years 8000 BTU Whirlpool window AC is unable to cool the living room (25ft long x 13 ft wide x 7.5 ft height) in a hot summer time. Are all 8000 BTU Window AC created equal regardless manufacture and other parameter? If not, what make one be cooler and more efficient than other? Can someone please recommend the best one of its kind in the 8000 BTU category? Advance thanks for any kind of help.