The problems associated with portable air conditioner window kits are having a kit that does not fit, having to remove the window screen to install the kit, and kit incompatibility with casement and crank-out windows. Window kits also have to be re-installed each time the portable AC is moved.
Portable AC window kits come with a foam or plastic window bracket that covers the open window area surrounding the exhaust vent hose. The window bracket should be trimmed to fit securely into the window opening, and if the portable AC is moved to a different-sized window, a new bracket is necessary. The window screen needs to be removed with some window kit installations, making it easier for insects to enter through the exhaust vent and other openings.
A portable AC window kit usually includes a 4- to 5-foot vent hose that cannot be extended, limiting placement options in crowded rooms. Lengthening the exhaust hose can cause the air conditioner to overheat and reduces energy efficiency. Standard window brackets are too small to fit vertical sash windows and cannot accommodate windows that open outwards, such as casement windows.
Portable air conditioners require more power than window air conditioners to cool the same amount of space, which makes them less energy efficient and more expensive to operate.