In the user reviews we consulted, the portable air conditioners that owners recommend most often are larger units with at least 12,000 Btu of cooling power. These larger units can cool spaces of about 350 square feet. In this size class, no portable air conditioner receives more positive reviews than the NewAir AC-12000E (Est. $460) . The majority of owners are pleased with this unit's cooling power, with many saying it can cool spaces much larger than the 425 square feet claimed in its specs. However, some users disagree, saying it can't lower the temperature by much even in a small room. Another common complaint is that this air conditioner is too loud.
However, owners are pleased with how easy the NewAir is to install and use. Several users mention that it's very easy to move from room to room. Another feature users really like is the self-evaporation system, which automatically exhausts moisture along with heated air. Most users say this completely eliminates the need to drain water from the machine.
If the 12,000-Btu NewAir isn't powerful enough for your needs, you might consider an even larger unit, such as the 14,000-Btu Whynter ARC-14 ($495 ) . Like the NewAir, the Whynter has a self-evaporation feature (referred to as "auto drain" by the manufacturer), which removes water vapor through the exhaust vent. Users generally say this feature works well, and they also find the Whynter very quiet. When it comes to actual cooling performance, however, reviews for this air conditioner are a bit more mixed. While many owners praise the Whynter's cooling power, we saw more than the usual number of complaints that it doesn't get the room cold enough.
The Soleus LX-140 ($455) has the same cooling power as the Whynter. However, it adds one other feature the other air conditioners in its class don't have: a 14,200-Btu space heater. Most reviewers who rate this unit discuss its performance as an air conditioner only, but the few who have tried it as a heater find it very effective. Most owners praise its cooling performance as well, saying it keeps a room cool even on the hottest days.
Users also find this air conditioner very quiet, and they like its futuristic looks. When it comes to durability, however, the Soleus doesn't stand up to the competition. We read many complaints from owners who say that their units broke down after less than a few months of use. Another common problem is leakage. This unit does not shut off automatically when the water reservoir is full, and several users say that their machines overflowed when left on overnight.