APC makes multiple lines of devices. The lower-end devices are not so great. But the SmartUPS line is solid. No fans or noise of any sort, unless the power is o

APC makes multiple lines of devices. The lower-end devices are not so great. But the SmartUPS line is solid. No fans or noise of any sort, unless the power is off and you’re draining the battery. And if you’re draining the battery, then you should pay attention to all that noise and be in the process of shutting everything down safely, so that you can survive whatever caused the power outage in the first place. The point of a UPS isn’t that you keep running for days regardless of the fact you’ve lost power, it’s that when the power does go out you don’t lose all your work, and you’ve got a few precious minutes to shut everything down safely. If you don’t use a piece of equipment the way it was designed to be used, then that is all on you, and not the equipment that you are failing to use correctly. Note that APC is owned by Schneider, a company that specializes in making the really big UPSes of the sort they go into data centers and are used to provide short term power for entire buildings. They know what they’re doing.