If you are trying to cool a kitchen of any size, an area that receives full sun, or a room that's larger than 300 square feet (which is about 15 feet by 20 feet), you need the power of a large in-wall or window air conditioner. That means a minimum rating of 9,000 BTU, a beefy compressor that blasts a sufficient amount of icy air and a fan that can circulate it through the entire space. Be careful stepping up too much, however, a unit more powerful than 12,000 BTU will require a 220-volt outlet, which means you'll probably need to call an electrician.
Among air conditioners in this size category, we found the best consensus among experts and owners for the Frigidaire FFRE1033Q1 (Est. $275). Though it's not the absolutely top-rated model in one independent test, it scores well enough to earn Recommended status. It performs competitively with other air conditioners in this class when it comes to cooling, though noise levels could be better and the model is judged to be tougher than others to install. On that last point, at least one expert disagrees. Popular Mechanics describes installation as simple, "with vinyl side curtains that slide into either side of the metal housing and lock tightly into the window frame. No bugs creeping in here," says Heidi Davis. She also likes the thermostat-equipped remote control, which "allows you to see, set and maintain room temperature without having to get up."
The Frigidaire FFRE1033Q1 is Energy Star Qualified and rated at 10,000 BTU -- appropriate for a room of up to 450 square feet. To keep humidity in check, it's also capable of removing as much as 3 pints of moisture from the air per hour. Like its little brother, the 8,000 BTU Frigidaire FFRE0833Q1 (Est. $220) that's profiled in the section on air conditioners for medium sized rooms, there's an ionizing air filter for removing allergens. We've seen that cited as a plus in several user reviews, but no expert has verified that it's indeed more effective than a standard air filter.
Big air conditioners like this one aren't reviewed by users as often as medium or small air conditioners, but we found a reasonable amount of mostly positive feedback for the Frigidaire FFRE1033Q1. Walmart.com is where you can find the biggest collection of reviews, and we saw more than 100 there. Most are happy, with about 92 percent saying they would recommend the air conditioner to a friend. It earns a rating of 4.4 stars. There's less feedback at Amazon.com -- around 50 reviews overall -- but satisfaction is nearly as high; the FFRE1033Q1 earns 4.2 stars. A few say they AC is louder than expected, doesn't cool as well as hoped, or that it arrived damaged or otherwise defective. Most are pleased, however.
If you want or need something a little more powerful, consider the LG LW1215ER (Est. $385). This Energy-Star Qualified, 12,000 BTU unit is about as powerful an air conditioner as you can find that will run on 115V AC and not require a dedicated 220 V line, and it can handle a room of up to 550 square feet. The small remote control lacks a display, but is otherwise full-featured and lets you control all functions, including temperature settings, from across the room.
The LW1215ER is a new for 2015 model that's not yet been extensively reviewed, but its predecessor version, the LG LW1214ER (discontinued), was well received by users and experts. ConsumerReports.org's Mary H.J. Farrell notes that it was one of the top models in its size class in the site's most recent round of testing. Since the two ACs are very similar, we expect the LW1215ER to deliver similar performance. User feedback, while very limited thus far, is largely positive with the only negative comments we spotted address a unit damaged in shipment and complain about an older model.
A 12,000 BTU air conditioner is a hefty beast to install in most cases, and the LW1215ER weighs in at around 81 pounds. To make installation easier, this window air conditioner uses a slide-in chassis; you mount the outer sleeve firmly in your window frame and then slide in the air conditioner itself. But, while some slide-in chassis air conditioners can be mounted in a window or through a wall, the LW1215ER is designed for window installation only.
Finding an in-wall air conditioner to recommend proved to be a tall order. We couldn't find a reputable expert review of any current model, and even user reviews are largely hard to come by. That said, we did see higher than average feedback, and higher than average ratings, for the Keystone KSTAT12-1B (Est. $480). This 12,000 BTU air conditioner is designed to exclusively mount through the wall and cannot be installed in a window. It is Energy Star Qualified and can cool rooms up to 550 square feet. Unless you have good handyman skills you may want to hire a pro to handle the carpentry work needed to install the KSTAT12-1B, but you won't need an electrician as it runs on standard 115V AC. It does require a wall-sleeve, however, as one is not included.
This is a relatively feature-rich air conditioner, with a programmable 24-hour timer. The temperature sensing remote control includes an LCD readout to make use easier. Most owners are satisfied thus far -- it earns a 4.2-star rating at Walmart.com following roughly 40 reviews, with 90 percent of owners saying they would recommend the unit. Some note that the instructions could be better, though others say that installation is a breeze.
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