
The noise drives me nuts! Too bad the box went to the trash a few weeks ago or the unit would be returned asap. Not clear if the noise is a far or electrical; unacceptable regardless.
Additional info direct from the APC tech support -- the noise is a fan and the fan is on 100% of the time due to a change in design. The fan is very loud! The fan is a design change the noise is a known issue that will not be addressed. Completely unacceptable level of noise for such an expensive device. Get more detail about
APC BR900 900VA Back-UPS.