If you’re like us, the mere thought of a blackout or power surge makes you cringe. Resulting data loss can be devastating and can leave you with irreparably damaged hardware. Never fear, though: A UPS device can mitigate your worries by delivering constant power levels to connected equipment and maintaining appropriate voltage in the cases of outages or surges. Whether you manage a large group of servers or just a few desktop computers, deploying a UPS in your infrastructure could be one of the best (and easiest) decisions you ever make.

Before you hand your money over to a particular vendor, you need to address several preliminary questions within your organization. How often do power outages or power surges occur in your area? How many pieces of equipment do you want to protect, and what is their total wattage? How would your company be affected by a power loss? These questions—along with the considerations that follow—will help you determine the type of UPS you need.

Choose the Right Type
There are three basic types of UPSs: standby (offline), line-interactive, and online. Although the three types are similar in functionality, they have distinct differences.

Standby. A standby UPS uses the commercial AC line as its primary power source, and when a power outage or voltage drop occurs, the primary source switches from the AC line to the UPS’s internal battery. This switch between power sources happens quickly but isn’t instant—it should be brief to avoid causing your equipment to shut down. Standby is the cheapest UPS type and is intended for equipment such as desktop computers and fax machines.

Line-interactive. The line-interactive UPS uses an inverter/converter, which serves two purposes: charge the UPS’s internal battery and convert the battery’s DC power to AC power to run your connected equipment. The advantage of line-interactive is that the inverter/converter is always connected to the UPS’s output, providing a faster response time to power failure. Although line-interactive provides better protection than standby does, the primary power source is still the AC line, leaving it one step behind the third type, online.

Online. An online UPS simply offers the best protection for your equipment; it’s the only type that doesn’t use the AC line as its primary power source. In this case, the battery is the primary power source and constantly supplies power to your connected equipment, eliminating any transfer time between primary and secondary power sources. Although it’s the most expensive type of UPS, online will give you the most protection and is most suitable for larger, mission-critical systems, for which power outages are unacceptable.

Output Capacity
Selecting a UPS capacity is a crucial factor in your purchase. Vendors use volts × amperes (VA) to measure the amount of power that the UPS will supply to your connected equipment. For the purpose of this enterprisefocused buyer’s guide, vendors provided data for UPSs that offer capacities greater than or equal to 1000VA. As a rule of thumb, you should always purchase a UPS with a capacity of about 20 to 25 percent higher than the total wattage of the equipment you need to protect. You also need to factor in any future additions you might make to your IT infrastructure: Buying a higher-capacity UPS upfront will save you money, as opposed to purchasing further small-capacity UPSs down the road. Many vendors have online guides to help you make this decision, so be sure to visit vendors’ Web sites for advice.

Rack-Mount vs. Standalone
The two basic UPS form factors are standalone and rackmountable. Standalone refers to either a vertical or horizontal unit that sits on the floor next to the equipment you want to protect. Rack-mountable units, as their name implies, fit into your existing rack space and are probably the most logical form factor because they can be stacked to save space. UPSs are also available in a rack-mount/tower form factor, which lets you interchange between rack mount and tower.

Management Concerns
The UPS device is vital to any IT infrastructure, but before you make that final decision, determine whether management software is included with your UPS, especially if you’ll have multiple UPSs controlling critical pieces of equipment. Management software can automatically shut down your equipment and send alerts when power concerns arise. Also, consult your vendor about warranties and available on-site service, particularly if you have many UPSs, because replacing the batteries can be time consuming.

View Buyers Guide