I would like to buy UPS, but the review I read:
make me alert of one thing -- the noise of UPS. So, I understand when powering computer (from batteries) UPS fans kick in, making some noise. OK.
But in normal mode, when there is no blackout, and UPS is working in passive mode (not from batteries), does UPS make any noise (I think about its fans)? In other words -- do they work (spin) all the time?
Just in case, I have CyberPower CP900EPFCLCD or APC Smart-UPS 750VA (SMT750I) in mind particularly.
I bought APC Smart-UPS 750VA (SMT750I) and it is noisy all the time -- the noise is similar to grasshopper or older models of HDDs. When I close the windows (so all the street traffic is muted) the noise of the UPS is a bit annoying, but since fans in computer are louder I don't blame UPS for discomfort. Also I find that constant hum of the fan is more disturbing, that the ticking of UPS (as I said, it is similar to grasshopper).