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 US$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: American Power Conversion Corp.'s (APC's) Back-UPS ES 725 Broadband, Powercom's King Office KOF-575S, PowerWare Corp.'s PW3110, and Tripp Lite's Internet 750U. The other four devices -- APC's Back-UPS RS 800VA, Belkin Corp.'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.
Both models from APC earned a Best Buy award for their combination of great software, excellent features, and reasonable price. The Back-UPS RS 800VA was our favorite. This slender, good-looking tower is relatively tall but should tuck away under most desks -- and its size translates into outstanding run time: The RS 800VA sustained our power-hungry test PC (an Alienware system with a 19-inch monitor) for just over 29 minutes. Our gripes were relatively minor: The unit lacks surge protection for a coaxial connection, and installing the monitoring cables is a little fiddly.
APC's Back-UPS ES 725 Broadband is our other Best Buy pick. At $75, it's much cheaper than its bigger, more powerful cousin but still powered our test system for almost 16 minutes. The unit offers plenty of places to plug things in -- eight power sockets in total.
We saw some other worthy contenders, though. Tripp Lite's $75 Internet 750U powered our test PC for over 16 minutes, a long time for a relatively small and low-cost device. Powercom's King Office KOF-575S powered our test system for only 5 minutes, 15 seconds. However, that's still long enough to save and shut down, and the KOF-575S is the cheapest model we tested -- just $45. (If you have a less-powerful system than our test setup and a smaller CRT display or an LCD monitor, you'll get a longer run time.)
Both of the APC models use APC's PowerChute Personal Edition software, which is exceptionally easy to install and operate. It can use Windows XP's hibernation feature (Belkin's Bulldog Plus software also supports this), where all running programs are saved to disk and then restored when you reboot. We encountered some problems with the UPS programs that don't support hibernation; while they were able to force Microsoft Word and Excel to save the open document and close (so no data was lost), they didn't always close other applications properly, which could lead to lost data.
Tripp Lite bundles its PowerAlert software with its UPSs, and while that program provides ample information on the state of the battery, it's not quite as intuitive as APC's PowerChute. PowerWare's LanSafe 5 is powerful and intuitive to use, but provides little guidance through the confusing installation process.
PowerWare's stylish but pricey PW5115 tower is designed more for the business set than for home users: It provides ethernet and phone-line surge protection, plus some nice high-end features, such as built-in battery-health testing. We liked the PowerWare PW3110's widely spaced outlets, which easily accommodate AC adapters, but it suffers the same software installation hassles as the PW5115.
Tripp Lite's $180 OmniVS1000 offers two integrated 6-inch, battery-backed extension cords that keep even the biggest AC adapters from interfering with other outlets. However, you can't turn it off while it's plugged into the AC -- a deal-killer if you want to use the UPS as an easy way to turn off your PC and connected peripherals via one switch.
The Belkin F6C750-AVR has a tower case, but its AC outlets are positioned on top, and the adapters we used didn't sit comfortably in that location.
One point to keep in mind: All the vendors offer other versions of the products we review here, with different features and battery capacities. If none of the units we tested seems quite suited to your needs, do some research to find out what other models are available and what they offer.
How much power do you need?
When you go shopping for an uninterruptible power supply, you'll quickly notice that all the vendors list two ratings: volt-amp and wattage. Watts represent the actual power your provider is delivering. VA is typically called apparent power and is derived from the voltage applied multiplied by the current drawn. The main thing to remember is not to hook up more equipment to the UPS than the device can support; your load can't demand more watts than your UPS can deliver.
So how many watts do you need? You can work the answer out by multiplying the amperage rating of every component you want to power (usually listed on the component itself or on the AC adapter) by the voltage (usually 120 volts), and totaling that for all the components. The UPS you choose should have a higher VA rating than your calculated figure.
An easier way to get an idea of probable run time is to use the online UPS selector offered by vendors such as APC, PowerWare, and Tripp Lite. These tools provide a simple way to identify UPS products that might be suitable: You enter the components that you want to protect and how long you want them to keep running, and the selector comes back with several suggested products. Also consider which devices you plug into your UPS's battery-backed sockets. To extend run time, plug in only the core components that will allow you to save your data and shut down the PC, such as the computer itself and the monitor, but not the speakers and printers.
Note that laser printers should never be powered through a UPS -- they draw a lot of power when printing and can overload it.