That’s because the portable units require more maintenance than a traditional A/C.
For an air conditioner to truly cool your home, there has to be a way to remove hot air and exhaust that’s created by the appliance. Many portable units have tubes that can route the hot air through a window, but it’s a short-term solution, Hill and Welkin say. This is why, if you see a unit marketed as a ventless portable air conditioner, it's probably not truly ventless or an air conditioner, but rather either requires a tube or is actually an evaporative cooler.
“If you have a tube hanging out of your window, that’s temporary,” Welkin says.
Air conditioners also create condensation when they’re on, so most portable A/Cs have a drip pan, similar to the kind you’ll find under a portable refrigerator, and that pan has to be emptied every few hours.
“That is extremely inconvenient in the long term,” Hill says.