Experts are right to point out that portable air conditioners often fail to match the performance of cheaper-to-buy window units. But in many instances, a portable AC may be your only option—say, in a basement lacking full-size windows. Plus, while even the lightest window units are a hassle to move, portable air conditioners are easy to wheel between rooms. So if you wanted air conditioning in three separate rooms but didn't want to outfit each with its own window AC, a portable unit like the Haier HPN12XCM would offer a smart compromise. Available at Amazon; $445.