Uninterruptable Power Supply (UPS) Unless you're Fred Flintstone, your computer runs on electrical power that you get by plugging the power cord into an outlet in the wall. You depend on that outlet delivering consistent power for your PC. However, most people don't realize that, depending what area of the U.S. or the world you live in, this power source can be very unreliable. Brownouts, blackouts, or power surges occur more frequently than you think. The results range from data loss to a damaged PC. To protect your PC against such events, you should seriously consider getting an Uninterruptable Power Supply (UPS). Possible Power Problems The power from the outlet is never 100% consistent, it constantly fluctuates. Usually, that fluctuation is very minor and does not cause any problems. But sometimes the power level dips quite a bit below normal. This can be caused by a sudden surge in power demand, e.g. on a hot day when everybody turns on their air conditioners. This dip is called a brown-out. A blackout occurs when the power stops completely. This could be caused by an equipment failure at the power company, damage to the power line by a thunderstorm, or even a planned outage when repairs need to made or the power company rotates power outages to compensate for a high power demand as in the summer with air conditioners sucking up too much energy. A power surge can occur if a lightning strikes a power transformer in your area. It introduces a sudden surge of energy into the transformer and if this surge is strong enough, it will travel through power lines or phone lines, into your house and into your PC. Possible Damage A brownout or a blackout results in a loss of power, which causes your PC to reboot or shut down in the middle of whatever you're doing. You'll lose data because you didn't save your work, or because of the power loss your hard drive crashes and all files on it are gone. A power surge results in too much power suddenly going into your PC, which causes motherboards, processors, modems and/or other parts of the PC to be literally fried. You need to replace the part to get your system working again, because there is no way to repair a fried electrical component. And don't think that those cheap $10 surge-protected power strips can protect against this type of damage, they are considered useless. The only way to protect your PC against this is an Uninterruptable Power Supply (UPS) How a UPS works A UPS is designed to make sure the PC gets the power it needs at a consistent level from the outlet or from the battery inside the UPS. The UPS is usually a pretty ugly and pretty heavy box that you hide underneath your desk. You plug it into the wall and your PC and monitor into the UPS. The UPS contains a battery that is constantly being charged to stay at maximum capacity. When the power drops below a certain level (a brownout), or fails completely (black-out), the UPS immediately (within a millisecond or two) kicks in and starts supplying the PC with power from its battery. Of course the battery in the UPS does not last forever, and it alerts the user via an audible alarm that the power has failed so that the user can save any data and shut down the PC gracefully. BTW - Another good indicator that the power just failed is when all the lights go out and you hit your shins on the cast-iron frame of your antique coffee table while clawing your way through the dark trying to find the flashlight whose batteries are emtpy. A good UPS can be connected to the PC via a serial or USB cable. You install special software on the PC, which enables the UPS to automatically shut down the PC in your absence in case of a power outage. This is very convenient if you leave your PC on all the time or even just step out for lunch. In addition, a UPS usually has a good surge protector built in, that actually works and prevents power surges from travelling into your PC through the power line. A good UPS will also have a surge protector for your phone line to prevent a power surge entering your PC through the phone line plugged into your modem. Newer UPS's have usually multiple outlets (6 or 7). Half of them are battery backed-up, meaning every device plugged into one of those outlets will be supplied with battery power in case of a power outage as well as surge-protected. The other half is surge-protected only. In the battery backed-up outlets you should only plug in the most important pieces: The monitor so you can see what you're doing and the computer itself. These are the only two things you need to shut down your PC in a critical situation. Everything else, such as printer, speakers, etc. should be plugged into the surge-protected outlets. Tip: Never plug a power strip into one of the UPS outlets. Not only will you reduce the back-up time provided by the battery, you also introduce a weak link in the chain which can pose a safety hazard. How to buy the right UPS The most important part, as Tim "The Toolman" Taylor would say, is power. You need to calculate how much power you need so that you can make the right choice. UPS power is expressed in volt-amps, or VA - most UPS will be labeled with a VA Rating to help you find the right one. Don't worry, we're not getting into much electrical engineering here, we'll keep it simple. Calculate your power needs Instead of trying to figure out the volt-amps rating for every single device in your PC and adding them up, let's just play it safe and assume that the maximum power you'd need for your PC is the volt-amps that the power supply in your PC needs. Turn off the PC and take the cover off so that you can see the power supply. Look for the sticker with the specs and find the volt and amp rating, write them down and multiply them. Now look on the back of your monitor for the same data, write it down and multiply it. Now add the two products and you'll have a good number to work with. For example, if you have a 115 volt/2.5 amp power supply, the VA rating would be 115 * 2.5 = 287.5. Adding to that the monitors VA rating of e.g. 240, you would need a UPS with a VA rating of at least 287.5 + 240 = 527.5. Alternatively, you could just add the maximum power (in watts) of the power supply and the monitor, e.g. 250 W power supply and 140 W monitor, and multiply it with a conversion factor of 1.4 to get an approximate VA rating of (250 + 140) * 1.4 = 546. Either method tells you that you should be looking for a UPS with a VA rating of 550 or higher. Additional features to look for The next thing you should consider is how many outlets do you need to be battery backed-up and how many surge-protected. As a bare minimum, I would recommend 2 battery backed-up (for the monitor and the computer) and 2 surge-protected (for your printer and speakers) outlets. Also be sure to get a UPS that has a user-replaceable battery. The battery in a UPS lasts several years, but eventually will need to be replaced. It is a lot easier to just order the replacement battery, have it shipped to you and plug it in yourself, than having to ship the UPS to the factory for the replacement and be without protection in the meantime. Another important feature is the additional phone line surge-protector. You should have this because, as described earlier, a power surge can enter your PC through the phone line. Make sure that the UPS has a decent status indicator. It should at least tell you whether the UPS is running on AC power or on battery. Additional features can be a building wiring fault check and power load on the UPS. Some UPS's offer an automatic shutdown feature. They come with a serial or USB cable that you connect to the PC and some software that you install. When you have a power failure, you can program the UPS to save all documents, close all applications, and shut down the PC gracefully in your absence. If you always turn your PC off when you are not at your desk, then this feature is probably not important to you. But if you leave your PC on 24/7, this is a very nice bonus feature. Last but not least, any decent UPS comes with an equipment protection warranty. This means the manufacturer of the UPS claims to pay you up to a certain amount of money to replace your computer equipment if the UPS failed and your PC was damaged even though it was properly connected and secured by a UPS. While this is a nice feature, I have not spoken to a person yet that actually was in this situation and could shed some light on how their claim was handled. If you have been in this situation, I would like to hear from you - alex@pcnineoneone.com - and hear your experience. If you are interested in a recommendation, check out my review at http://www.pcnineoneone.com/reviews/other/apcbupsp.html on the APC Back-UPS Pro 500 that I am currently using myself. http://www.pcnineoneone.com