Though it can be tempting to blast away hot air with the largest portable air conditioner you can afford, experts say it's better to select the right size for your room. This lets the unit run long enough to dehumidify the air as much as possible, which will make your room more comfortable. For rooms smaller than 400 square feet, look for a portable air conditioner between 8,000 and 10,000 Btu for the right combination of cooling and dehumidifying. The exceptions to this are spaces that receive extra heat. Kitchens that are 200 square feet and larger, and rooms larger than 300 square feet that receive full sun will need additional cooling power. Select a larger portable air conditioner for these areas.
Smaller portable air conditioners, also called mini air conditioners, offer many of the same features as the large portable units. For easiest maintenance, a self-evaporative system automatically disperses moisture out the vent hose, minimizing the need to empty a water reservoir. The best mini can also function separately as a dehumidifier. Many owners appreciate this option when the weather is muggy but not hot enough for air conditioning. A built-in washable filter removes minor particles from the air, and units with an additional carbon filter can also screen out mold, pollen and dust.
Owner ratings easily place the NewAir AC-10000E (Est. $400) far ahead of the competition. The 10,000-Btu unit is compact and efficient with a low-maintenance design. "If performance, portability and price are tantamount in your search for an air conditioner, the NewAir AC-10000E is a fair option, especially for quickly cooling down bedrooms, small offices and personal spaces under 300 square feet," says Gregory Han with ApartmentTherapy.com. Its biggest drawback is the noise. At 54 decibels, it's louder than most models of this size, measuring closer to large, 12,000-Btu air conditioners.
Even though it's also a 10,000-Btu air conditioner, reviews say the Haier HPN10XCM (Est. $370) is powerful enough to keep up to 550 square feet cool (though some say it can struggle to keep the temperature low on hot days). Its effective self-evaporation system means owners rarely have to empty the water reservoir. Another benefit -- it's one of the quietest portables on the market. Though it has an outstanding warranty, after contacting Haier many owners say customer service is subpar and report long delays for warranty issues.
The Koldfront Ultracool PAC801W (Est. $290) is an excellent value, say reviews. It's packed with features like a 24-hour programmable timer, an extra carbon filter and the ability to function as a dehumidifier only -- all for about $300. In fact, many users are so impressed by the Koldfront that they purchase another to cool other parts of their homes. At 8,000 Btu, this mini air conditioner doesn't have the cooling capacity for rooms over 250 square feet.