1500VA is more than enough to provide 30 minutes or longer of backup power for your computer and network gear.
I have an APC 1500VA BackUPS UPS on this system. It provides protection for this computer (see my System Specs) plus my cable modem, Netgear wireless router, and 4-port Ethernet switch. And note I have two 24" LCD monitors on this system.
Right now as I type this in my browser while streaming Pandora, according to the LCD display panel, this UPS will provide 55 minutes of backup power. Killing power to one monitor and I have an estimated 78 minutes.
If I shutdown this computer during a power outage, the UPS will keep my network alive for about 4 hours so I can still access the Internet via my wifi connected devices (if their batteries have not died!).
BTW, it is important to understand backup power during a power outage is only a
minor bonus feature for using a "good" UPS with AVR (automatic voltage regulation). It is the 24/7/365 AVR feature protecting your connected devices from powerline anomalies that is the primary feature and reason to use a "good" UPS on our computers. Surge and spike protectors (S&SP) are little more than fancy and expensive extension cords as they do nothing for low voltage events like dips (opposite of spikes), sags (opposite of surges) or brownouts (long duration sags). And for
excessive surges and spikes, they simply shut off power (if working properly), hard-crashing your computer - never good.
Also, never connect a UPS to a S&SP. Likewise, never connect a S&SP to a UPS. The AVR circuits may see the power coming from a S&SP as "dirty". And if on the output side, the AVR circuits may see the load as unstable.
And FTR, don't buy into the falsehood you don't need a "good" UPS with AVR if you live in a country with a stable power grid.
Any major appliance in your home can produce destructive anomalies. Refrigerators, water coolers, microwave ovens, toasters all send surges, spikes, dips and sags EVERY TIME they cycle on and off.
Advanced, more expensive high-wattage appliances may
attempt to suppress dumping such anomalies on the circuit –
"IF" they are not damaged and are working properly. But low-tech cheap appliances will not. A cheap, $15, 1500W hair dryer made in some obscure factory in the backwoods of China, using parts from a similar factory upriver, comes to mind.
Whole-house surge arrestors may protect your equipment from surges coming off the "grid" - such as lightning hitting the transformer on the pole down the street. That is where most destructive surges will come from - most, but not all. Whole-house arrestors do
not protect you from surges and spikes that are generated by other high-wattage devices within your own home or office. And of course, they do absolutely nothing for low-voltage anomalies that can cause your computer to suddenly crash.
While APCs tend to cost a bit more, I still prefer them (though I have nothing against Cyberpower). FTR, I also have a good UPS on my home entertainment system (Onkyo receiver, cable/DVR, Blu-ray player, Roku, and 55" OLED TV), and even my garage door opener!
Hey! I live in
Tornado Alley!