Arvin Argh :
By that Seasonic price, it would then be cheaper to buy APC UPS including battery replacements. Really, nothing of value comes cheap.
Show me one number that says you need that stuff. Some of the most expensive 'solutions' are best called scams when so many 'fear' a threat that does not exist. If you need protection for one appliance, then you need it for all.
So again, what number says you need AVR? For example, incandescent bulbs can dim to 40% intensity. Voltage that low can be potentially harmful to motorized appliances (ie refrigerator, air conditioner, dishwasher, furnace). And ideal for computers. How often is your voltage dropping that low? What is a threat?
International design standards for 120 volt electronics (long before PC existed) defined up to 600 volt spikes without damage. Again, numbers that so many forget to learn. Many 'feel' voltage variations must be destructive. That alone is why so many recommend AVR and other 'magic' solutions. How many first defined the threat - with numbers?
That battery backup UPS is temporary and 'dirty' power so that unsaved data can be saved during a blackout. Not for low voltages. For zero voltage. Same voltages (low and no) cause no hardware damage.
BTW, none of that discusses a surge. A surge is completely different. How fast can an AVR respond? At best, a UPS may respond in 10 milliseconds. Meanwhile something completely different and destructive - called a surge - is done and caused damage in microseconds. Again, why do others recommend without numbers? Propaganda sources that promote 'miracle box' solutions forget numbers to promote their products to the naive. Informed consumers always want numbers.
Did they also forget that best protection at a computer is already inside the computer? Your concern is an anomaly that might overwhelm that superior protection. These events might occur once every seven years. And must be averted at the service entrance - where all wires enter your building.
Which anomaly so concerns you? Frequency variation, harmonics, floating ground, sags, overvoltage, power factor, EMI/EMC, reverse polarity, RFI, ... nothing averts all. Which one is AVR suppose to address? Any by how much? Recommendations without numbers are a first indication of hearsay or junk science recommendations. Introduced are a few that might concern you - that AVR does not solve. Numbers separate informed recommendations from urban myths.