This is a difficult thing to answer.
I personally feel that raw "loudness" isn't necessarily as important as the timbre of the sound in question. Like if its super quiet but the sound is incredibly annoying, thats worse IMO than a slightly louder noise that is very unoffensive. As a result just raw dB isn't super helpful in determining if you can deal with this projector or not.
This projector's fan sounds are roughly equivalent to the old Xbox 360's fans in terms of both loudness & timbre. Inside this unit you have multiple ~80mm fans running at variable speeds. The speed varies with temp, which varies with ambient temp, ambient humidity, altitude, your lamp settings, and subject matter being displayed. As a result, the sound produced in your installation will maybe be different from someone else's. Plus, on top of that, what is "not that loud" to someone else may be "horrible sounding" to you, or vice versa.
The up side on this is Amazon has like a 30 day return policy and they make it relatively painless if you decide it sucks or doesn't fit in the space you planned for it or whatever.