Why we rank portables by SACC
Portable air conditioners used to be sold on their ASHRAE rating. The U.S. Department of Energy now also requires a Seasonally Adjusted Cooling Capacity (SACC), which accounts for the heat a portable unit leaks back into the room. The difference is large: in this list, portables boxed as 14,000 BTU deliver about 10,000 BTU of real cooling, and an 8,000 BTU box can mean 5,000.
That is why a portable can look big enough on the box and still struggle in your room. The finder compares the SACC figure with what your room needs. When a maker does not publish SACC, we label it instead of guessing.
Window or portable?
For the same real cooling, window units are usually cheaper to buy and run, and quieter. Choose a portable when a window unit will not fit your window or is not allowed, or when you want to move it between rooms. U-shaped window units straddle the sash, so the window still opens and most of the noise stays outside.
Sizing in one line
Find the BTU your room needs with the BTU calculator, then pick a model whose real cooling is at or slightly above it. Much bigger is not better: an oversized unit cycles on and off and leaves the air clammy.