I tested the 10,000-BTU version of the Q Series window AC in an 120-square-foot upstairs bedroom that gets very little flow from my home’s central AC. —Martin CizmarDreo Portable Air Conditioner 740S (10,000 BTU) for $700: Look, I’m loving the new generation of portable air conditioners but not because they’re portable. GE AWAS05BBA Window Air Conditioner Unit (5,000 BTU) for $231: This 5,000 BTU unit is less powerful than our favorite budget window air conditioner pick from GE. LG Window Air Conditioner Unit (12,000 BTU) for $379: The LG 12,000 BTU Smart Window Air Conditioner offers efficient large-room cooling at a surprisingly low price. A cheap window AC unit will save you money at first, but you may end up shelling out more in the long run.