Window ACs only work in windows because they rely on the opening to vent hot exhaust, manage drainage, and keep outside air ...

For example, window units are generally more efficient because they're sealed tightly in a window frame, whereas air may escape around the hose that's attached to a portable unit.

The cost between window air conditioners and ductless mini-split cooling systems are fairly significant, with each window unit costing up to $600 and a ductless system costing up to $4,000 per unit.

Despite pausing these standards for centralized climate control units in February 2025, the current administration has yet to roll them back for window air conditioners.

Best Window AC Units of 2025 Here's how to tell if your AC filter needs changing The only real way to know it's time to replace your AC filter is by checking on it every so often.