We've all been through power failures--and they're never any fun. It's bad enough when the juice goes out before you've ground your morning coffee; it's far worse to have a blackout roll over a data-laden spreadsheet or a term paper you forgot to save.
These days there's little reason to risk such a loss. Protection, embodied in an uninterruptible power supply, has never been more affordable. One of the eight units reviewed here costs only $45, and one of our Best Buys goes for $75. And aside from being able to step in seamlessly and sustain your PC while you save your files, even the cheapest UPS models provide some surge protection, guarding your network, phone, and coaxial TV connections. All of the UPSs we tested come with software that can shut your PC down automatically if you're not there.
For our Spotlight on UPSs, we picked eight units designed for home or small-office use and tested how well each one handles a power loss: How long will it run a power-hungry, high-end PC and monitor? And how effective is the provided software that watches over the UPS and automatically shuts down the computer?
Four of the products we review here are low-profile units that have outlets on top and look like overweight power strips: APC's Back-UPS ES 725 Broadband, Powercom's King Office KOF-575S, PowerWare's PW3110, and Tripp Lite's Internet 750U. The other four devices--APC's Back-UPS RS 800VA, Belkin's F6C750-AVR, PowerWare's PW5115, and Tripp Lite's OmniVS1000--are more traditional-looking units that resemble small tower PCs. (The bigger, tower-style units usually have a larger battery and are more suited for business systems that run 24 hours a day.) All eight offer UPS basics: surge protection; battery backup; and a USB or serial port that, with software you run on your PC, allows a communications link between the UPS and your PC for controlled shutdowns during a power outage.
Each vendor offers equipment-damage insurance--if a power spike damages hardware that you have properly attached to the UPS, the company will, in theory, cover the cost of repair or replacement. Read the vendor's policy carefully, however--the terms of the policies vary.
After features, the battery capacity has the biggest influence on cost. Some of the models, such as our Best Buy APC Back-UPS RS 800VA, have siblings that offer greater or less capacity and run-time potential. For guidance on choosing the right size UPS, see "How Much Power Do You Need?" and consult the features chart.