I have 7 of the model grayed-out in the photo, and while this one has more power, that one could be clipped to a window cill, which is what I've done with mine.
Nonetheless, I whole-heartedly recommend these fans at any size (I also have a Vornado 3-speed floor fan). They DO blast a column of air an impressive distance (on the high setting), and they ARE very quiet (on the low setting). The noise on the high setting is notable, but is not intrusive like it is with cheaper fans. It's more like "white noise." Also, Vernado has VERY good customer care. One of my fans had a rattle when it arrived, and they sent me another one immediately, only requesting that I cut the cord to the bad fan.
If anyone would like to know what the hell I do with 7 little fans and one bigger fan, here's my system for cooling my top-floor, south-facing apartment that used to get hotter than 85° inside when it was 90° outside (and didn't cool down very well when the sun went down):
I have no A/C, and on hot days (for less than A/C would cost to buy and run), I use all these fans to channel air from the shaded (cool) side of my apartment to the sunny (hot) side, and the hot air out.
On the night before a hot day, I open all the windows and run all my fans full-blast (OK, yeah, that gets a little noisy) until I go to bed, so I can cool the apartment down as much as possible (I aim for 70°). Then close up all the windows.
Between pre-cooling the apartment with these powerful fans, and putting sheets of foamboard in my south-facing windows to block some of the direct sunlight (gap at the top still lets light in), on a 90° day, the apartment stays in the low 70s until at least mid-afternoon.
When it does get above 75° in the rooms on the hot side of the apartment, I daisy-chain 2 fans in the middle of the apartment to pull cool air from the shady side to the sunny side. If it's cool enough outside on the shady side (usually is by late afternoon), I open my 3 windows and turn on the 3 fans mounted in them, facing inward to bring in additional cool air.
On the hot side of the apartment, I run 2 fans pointed OUT the windows (cracked only to the width of the fan) to draw hot air out. (The last fan stays trained on my 18-bottle wine "cellar" which has no refrigerant so it only keeps the wine about 20° below ambient. To help the cellar keep the wine in the mid-50s, I channel cooler air toward it with one fan. Works like a charm.)
With this method, and variations thereon, depending on what the weather is doing, I've keep apartment — which used to get into the high-80s on a hot day — no warmer than 78° even when the weather is in the mid-to-high 90s.
Of course, you didn't need to know all that. But seeing as I'd bought these fans specifically with this system in mind, I thought it might be of some use to someone in a similar situation.
Much cheaper than buying and running a portable A/C for an apartment with windows that wouldn't accommodate the vents anyway.
PS: Where I live, late-September/early-October is by far the hottest time of the year, so I'm doing right now exactly what I described above.