If you need a window fan that can bring in cool air at night or extract hot air out of a kitchen window, you won’t find a better-equipped fan for the price than the Pelonis 9″ Twin Window Fan. After 12 hours of research, the Pelonis is the only fan we found for under $40 that’s quiet, powerful enough to be felt at a 20-foot distance, and reversible with a toggle switch, which means it’s a lot less fuss to reverse the airflow on your fan.
If you’re willing to spend nearly twice as much, the Bionaire Twin Reversible Airflow Window Fan (BW2300) has everything you could possibly need in a window fan. Its more powerful motors could be felt from 30 feet away, 10 feet farther than our top pick. You can toggle between three settings from the unit itself or with the included remote: both fans drawing air, both fans venting air, or one fan drawing and one venting at the same time. Additionally, the window fan can be adjusted to correspond with a built-in thermostat, though we think this feature is too finicky to be useful.
There are not many practical reviews for window fans. But we’ve been collectively researching room fans for 60 hours, and we think that lessons learned from that article applies to this category as well. Additionally, I was raised in an apartment in New York City for a decade where we used window fans exclusively. Between the constant summer operation and A+ dirt and grime of New York, we never had one last longer than two years. After reading many user reviews, it became clear that, compared to other parts of the country, two years is perhaps on the shorter end of a window fan’s lifespan.
While a room fan can circulate air within a room, a window fan can bring in cool air from outside or exhaust stale air from small bedrooms or kitchens. Additionally, they’re easier to install and much cheaper, in terms of both initial cost and power consumption, than an air conditioner. They’re ideal solutions to tricky airflow situations, especially in irregularly shaped apartments or homes or when an air conditioner would be overkill.
The ultimate truth, however, is that window fans are not designed to last. They’re difficult to take apart, difficult to clean, and the small motors, which are exposed to the elements but shouldn’t get wet, can become sticky after a year or two of running. It doesn’t make sense, therefore, to spend too much on fans like this; we looked for fans that are inexpensive. Second, they had to be able to reverse the airflow without manually taking the fan out of the window and changing its orientation. And lastly candidates needed to operate quietly but still have decent airflow, enough to move the air in a medium-sized room. We measured the sound that each fan produced on high with a decibel meter and recorded the distance where the fan could still be felt comfortably.
Most window fans will fit into a standard double-hung window frame. Installation is as easy as lifting the lower window frame, inserting the fan, and lowering the sash back down so that the fan is held into place by the weight and support of the window. There are some window fans, such as the Bionaire Thin Window Fan, that are designed for sliding windows that open horizontally and install much the same way. Irregular windows, such as crank-operated casement windows or French-door-style transom windows will not be able to support a window fan—at least, not well.
This year, we focused on the standard two-fan window models. We tested one slim model with three fans as well but found it didn’t have a reverse toggle switch. We’re aware that certain large single-fan models exist and can be mounted to the window sash. These represent a more niche product within the world of window fans and will require their own specific testing, which we hope to include in the future if there’s sufficient reader interest.
After studying 16 models of fans (and taking cursory looks at roughly three times that number), there is not an overwhelming amount of design variation among the manufacturers. A window fan is most often built around two identical fans about 9 inches in diameter and a small control panel centered between them. What changes, and what sets more expensive models apart, are the quality and power of the fan motors, and functional automated or remote-controlled settings with details like built-in thermostats or IR receivers.
The Pelonis was the least expensive fan we found that also had a reversible airflow switch. That alone wasn’t enough to make it our top pick, though. It was also the least expensive fan we found where both fan speeds can be controlled independently of one another (though their direction cannot), and it featured a built-in thermostat and generated wind force that could be felt from 20 feet away, which was on a par with most of the fans we tested but without much of the accompanying noise that other fans created.
According to the product’s specs on Home Depot’s site, the fan can circulate 1,400 cubic feet per minute (CFM). But that seems unlikely. We measured our runner-up room fan, the Vornado 660, as able to push 406 CFM. I happen to own this model myself, and there is just no way that the Pelonis circulates nearly four times the amount of air as the Vornado 660.
Bionaire, the maker of our upgrade pick, doesn’t disclose technical information like CFM on its website, so we can’t make direct comparisons based on (admittedly questionable) manufacturer-reported numbers. However, fan speed and power suggest that the Pelonis is about two-thirds as powerful as the Bionaire Twin Reversible Airflow Window Fan, our upgrade pick.
The noise of the motors measured between 60 and 65 decibels, about the level of normal conversation, with a mic held directly in front of the fan. If you are sitting more than 10 feet away from the fan, the sound blends in mostly with the rest of a room’s ambient noise. This was roughly average for all the fans we tested, except for the similarly priced, notably louder Holmes Twin Fan, which posted a reading of 75 decibels and released an annoying high-pitched noise.
We tested the thermostat as best we could, but like every built-in thermostat we tested, we found it to be imprecise at best. A thermostat could be useful, though, for people who like to sleep with their fans near them at night but don’t want the fans to constantly run. When the thermostat setting is engaged and the control temperature properly set, the fan is meant to pleasantly turn itself on and off as the room cools and warms.
While the Pelonis can be aligned vertically for use in slider windows, it’s best situated horizontally within double-hung window frames. The fan measures 24 by 13 inches without the extension and 31 by 13 inches fully extended. There is also an option for a 3.5-inch plastic extender, which can maximize the fan’s width to 34.5 inches when inserted. This should be plenty for standard windows between 24 and 34 inches wide.
The Pelonis is backed by a one-year warranty, but we’ve found Home Depot’s return/exchange policy to be extraordinarily lenient. A two-year warranty extension can be bought for around $7 more.
The Bionaire costs nearly twice as much as our top pick. You may find it’s worth the upgrade—you’ll get stronger fan power, fans that can each simultaneously spin in opposite directions of one another, and the convenience of a remote control. The fan’s force on the highest setting can be felt a full 30 feet away, which is 10 feet farther than our pick and 5 feet farther than any other model we tested. The Bionaire was a little louder than our top pick by about 5 decibels, probably on account of the extra fan power.
Bionaire makes a nearly identical model, the (BWF0910AR-WCU), which we also looked at. We can’t find a discernible difference between the two except for the price (our pick, the BW2300, is usually a few dollars cheaper). If you can’t find the Bionaire BW2300 for whatever reason, the BWF0910AR-WCU is a perfectly suitable replacement.
Bionaire does not publish technical details on many of its products (such as the airflow of its fans in CFM). Compared to our top pick, however, we measured the Bionaire producing about a third more power from its twin fan blades. Specifically, we felt 30 feet of force from the Bionaire versus 20 feet of force from the Pelonis. We’ve reached out to Bionaire PR for more concrete numbers.
The thermostat on the Bionaire was more precise than many of the other models we tested but still not great. Like our top pick, we did find that the thermostat was best used to automatically turn the fan on and off at night while we slept. It worked well enough for this purpose. But this is not as accurate as setting the temperature on a thermostat or even a window AC unit.
The Bionaire measures 24¼ by 12 inches without the the extension and 30 by 12 inches fully extended. There are also two 3-inch extenders, which can maximize the fan’s width to 36 inches when inserted.
Who else likes it? Wirecutter editor-in-chief Jacqui Cheng has used one in Chicago for three or four years and has been impressed by the power of the fan. “I bought this fan to help keep my bedroom cool in the spring/fall without having to turn on AC and that thing seriously moves a lot of air for its size,” said Jacqui. “The only finicky thing,” she added, “are the controls. It’s not entirely clear how to change the in/out flow or the speed. It’s not super intuitive; I have to basically read the buttons every single time (even though I’ve had it for years). But on the flipside, there are only a couple buttons and it’s not hard to figure out once you start pressing them.” She added that she had bought the Bionaire on the recommendation of a friend in NYC who had also used one for going on four years—so, anecdotally, this fan tends to last a little longer than average, and that could be another way to justify the expense.
Executive editor Ganda Suthivarakom has also owned one for four months and uses both airflows regularly. “At night, when outside temps are cool here in southern California, the fan can cool down my living room in five minutes.”
The Bionaire is backed by a limited one-year warranty. A two-year warranty extension can be bought for $8.50 more at the time of writing.
The Air King 20″ Whole House Window Fan is for large rooms or small homes. It’s mounted directly to the window sash, which allows free movement of the window behind it. But it’s far bigger than our pick, and about three times the price—a cost and size that put it out of the running as a possible pick. The Air King has a “Storm Guard,” a neat feature that allows for the window to be closed behind the fan during poor weather or when locking the home during a trip without having to remove the fan.
If your available window height is slim, or your window slides horizontally, the Bionaire Compact Window Fan is for you. Its 8-inch vertical height is 5 inches shorter than our top pick, and this allows it to slip into slimmer profiled windows than most standard window fans. A long thin shape and strong accordion supports make it ideal for horizontal sliding windows. We were also impressed by the stiff wind speed of the Bionaire Compact, which could be felt from 25 feet away during testing: 5 feet farther than our top pick but 5 feet shy of our runner-up. However, its lack of a reverse airflow switch and mixed user reviews removed it from the the running.
The Bionaire Remote Control Window Fan is nearly identical to our upgrade pick but a bit more expensive. We tested this model as well just to be sure but couldn’t find any discernible difference in performance. If you can’t find our pick for whatever reason, this is a very suitable replacement.
It doesn’t make sense to spend too much on a product that probably won’t last more than a couple of years. But the Holmes Dual Blade Twin Window Fan, about $10 cheaper than our top pick, was simply too cheap. During testing, this model was louder than many we tested, and the shrill noise of its motors was difficult to ignore. More sound doesn’t equal more power. This fan could only be felt from 18 feet away—the weakest performance of any model we tested.
For a higher price than our pick, there isn’t anything extra that the Holmes Dual Blade Twin Window Fan w/ One Touch Thermostat provides that our top pick doesn’t. You can spend $10 less on our top pick and get a better fan.
Like the Air King above, the single-bladed Lasko Electrically Reversible Window Fan is for large rooms or small houses. But it’s too large and specific for us to test just yet.
The Lasko Twin Electrically Reversible Window Fan is nearly the same price as our top pick, but pointedly mixed reviews and a lack of a remote control knocked it out of the competition.
Like the Lasko above, the Optimus 8-inch Reversible Twin Window Fan is too expensive for the limited features and functions it’s equipped with. The price, combined with a lack of reviews (nine at the time of publication), meant it couldn’t be seriously considered as a recommendation.
(Photos by Michael Hession.)
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