Others We Tested
EcoFlow Wave 2 for $1,299: Lisa Wood Shapiro tested the newest model for this update. The EcoFlow Wave 1 has cooled down my wife’s office for more than a year just fine—we can’t use a window AC there because it would block the fire escape. Lo and behold, there’s a new version that’s slightly cheaper (8/10, WIRED Recommends). It’s a little lighter than its predecessor at 32 pounds, yet has a higher 5,100 BTU rating (up from 4,000). New here is a heating mode rated at 6,100 BTU, so you can keep using it in the winter to warm up a room. The company says it’s best for rooms up to 107 square feet. You do need to place it near a window to have one of the included ducts connected to the vent to take hot exhaust from the back of the unit out of the room. What makes this unit versatile is how you can power it. You can use a standard AC outlet, but you can buy the version with a battery to keep it working when you don’t have access to power, or you can hook it up to solar panels. —Julian chokkattu
Dreo Smart Air Conditioner for $460: The Dreo Smart Air Conditioner not only cools a large bedroom effectively and quickly, it also can be controlled by the app in my iPhone. Along with the Dreo’s easy-to-use app, it can be paired with Amazon Alexa or Google Home. It has an easy-to-read LED display and control panel, along with a magnetized place for the remote, and louvers that open and close, adding to its robotlike aesthetic. The setup was easy, and I didn’t drill in a single screw, as I was able to close the window on the expanders. It’s not entirely clear how I was supposed to snap the hose into the window hole, but I shoved it in and it seems to fit in there. It’s not super airtight, which is fine. One of the issues with portable air conditioners is the single hose. It can create a vacuum in an airtight space; think pressure in your ears like an airplane. And it can create enough negative pressure that the room can potentially suck in hot air from the outside. So, leave the window open a crack. However, we now only recommend dual-hose portables, as they don’t create a vacuum and are more efficient. —Lisa Wood Shapiro
Zero Breeze Mark II for $999: With its 2,300 BTU, you won’t be able to get the same cooling power as with the EcoFlow Wave, but the Zero Breeze (7/10, WIRED Review) is much lighter at 17 pounds. This bundle includes a battery that will make the whole thing weigh about 30 pounds, but you’ll get four hours of use without needing to be near a wall outlet. Like the EcoFlow, you get a few vent pipes to direct exhaust away and direct cool air to a specific area, but unlike the EcoFlow, you can’t charge the battery and use the AC at the same time. —Julian chokkattu
Zero Breeze Mark III for $1,399: As WIRED contributor Chris Null notes (7/10, WIRED Review), the Mark III is both larger than the Mark II and quite a bit heavier, now 22 pounds. Add on the 1,022-Wh battery pack and you’ll pack on another 14 pounds, though that frees you from having to be near a power outlet. New for the Mark III is the fact that batteries can now be stacked and charged in sequence, each daisy-chained to the next (though at $600+ per battery, this can get pricey fast). Each Mark III battery also has extra outputs that can be used for other devices—one USB-C port, one USB-A port, and a 12-volt DC socket. However, the Mark II battery has all of the above plus a second USB-A port. No word on why this was removed. However, it’s a bigger, punchier unit by most standards and a worthwhile buy for outdoors enthusiasts.
BTU stands for British thermal units. In the case of air conditioners, BTU is a way to measure how much heat the compressor can remove from a room. It’s a quick and easy way to figure out whether an AC unit is powerful enough to cool your space. First, you’ll want to find the square footage of your room by multiplying the length and width. Then, use the US Department of Energy’s guidance on the BTU capacity you need. For example, a 150- to 250-square-foot room needs a 6,000 BTU AC unit or higher for adequate cooling.
Check the combined energy-efficiency ratio (CEER) rating. The specs on any air conditioner you buy should list a CEER rating, which is one of the best ways of checking the energy efficiency of a unit. You’ll usually see a number between 9 and 15. The higher the number, the less you’ll pay when the electricity bill comes around. A cheap window AC unit might save you money at first, but you may end up shelling out more in the long run. The US Energy Star program has a website that lets you browse AC units based on their CEER ratings.
Check local laws. Some cities, like New York, require installing brackets to support your window AC. A simple one like this model should do the trick, though we haven’t tried it out. You may also need to head to a hardware store for some plywood to make sure your window sill sits flat, but this depends on the type of windows you have and the AC model you buy. When installing, you should get a friend to help you out. These units can be heavy and difficult to hold, and the last thing you want is to drop one out the window.
Measure your window. Before you buy, read up on the supported window types and sizes for the AC unit you’re looking at, and measure your window to be safe. Make sure to seal any gaps as best you can with the included foam. (You can always buy more if you need it.)
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