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6 Factors to Consider When Choosing a Centralized vs Distributed UPS

understand that there is no one-size-fits-all approach. In fact, numerous factors come into play when choosing the optimal model for your particular environment. One of the first considerations is whether to deploy a centralized or decentralized solution. In a centralized set-up, one large UPS system is responsible for protecting multiple loads, with the option of installing the unit in a separate room or area away from the equipment it is protecting. Conversely, a decentralized UPS, also known as a distributed model, is installed directly in a server rack or adjacent to it, and must be situated near the equipment to which it is providing backup energy and power.  

Types of UPS Systems and Their Applications

Centralized UPS systems are generally designed with online, double-conversion topology, while distributed power supplies most often consist of line-interactive models. Topology refers to the central design of an uninterruptible power supply system. Of the three primary UPS technologies available today, each offers different performance characteristics and varying degrees of protection:

Online double-conversion

This type of UPS system delivers continuous protection against all nine of the most common power problems, isolating equipment from any incoming power anomaly. Because the output voltage of an online UPS is entirely regenerated by a sequence of AC to DC conversion, followed by DC to AC conversion, it creates a supply of clean, consistent power regardless of any incoming instabilities. Online UPSs are the best choice for critical applications and those involving highly sensitive equipment, such as data centers, communications hubs, healthcare environments and other installations where continuous, clean power is a business-critical requirement.


Shielding connected devices against power failures, surges, sags, and under- and over-voltage conditions, line-interactive UPSs are typically used in enterprise network applications to protect IT equipment such as switches, servers and storage. Compensating for under-voltage and over-voltage circumstances without using the batteries, line-interactive models offer high reliability and efficiency, though their batteries cannot power equipment for very long and the topology may not provide adequate protection for mission-critical and large industrial applications.


Also referred to as an off-line or passive system, standby systems provide the most basic type of UPS protection. Safeguarding connected equipment against sags, surges and power outages, this type of UPS allows equipment to run off of the incoming utility power until it detects a problem, at which point it switches to the battery. Standby topology is best suited for less critical applications such as home and small office environments.

Determining the best topology for your facility depends on a number of factors, including the level of reliability and availability required, the type of equipment being protected, budget, risk tolerance and more.

6 Factors to Consider When Choosing a Centralized vs Distributed UPS

To determine whether your environment is better suited for a centralized or distributed UPS system, it is critical to weigh all of the advantages and disadvantages of both strategies.

Some of the greatest benefits to centralized UPSs are higher efficiency and reliability; the ability to isolate all maintenance, repair, replacement and security to a single point; and increased visibility. On the other hand, centralized power systems yield higher upfront costs, both for the purchase price of the UPS and its installation. Additionally, the installation process ― including power distribution from the UPS to the protected equipment ― is typically more complicated with centralized supply systems.

Decentralized solutions yield their own set of advantages and disadvantages. For instance, they afford a lower initial investment cost, easier installation and maintenance, and more flexibility for moves, additions and changes. Yet at the same time, the strategy can add managerial complexity while decreasing security.

Also, it is important to recognize that the two UPS strategies aren’t mutually exclusive; many sectors such as data centers and healthcare environments deploy a combination of UPSs. For example, while a large hospital might rely on a large, centralized UPS system, specific departments within the facility ― such as a lab, intensive care unit or radiology department ― are often supported by individual decentralized UPSs. In this way, designated equipment is able to receive redundant protection or extended runtime.

When assessing whether your organization would be better suited for a centralized or decentralized UPS, it is important to weigh the following six considerations:

  1. Cost — When it comes to overall price tag, centralized and decentralized UPSs both offer distinct advantages. Distributed UPS systems require less capital to purchase, complemented by lower installation costs due to their plug-and-play setup capability. However, because they are comprised of multiple UPSs that must be serviced and monitored individually, decentralized systems often generate greater service expenses than their centralized counterparts. Meanwhile, centralized UPSs typically yield a better return on investment due to their higher efficiency rating, which reduces operating costs, coupled with lower maintenance expenses. Yet they may also require approval as a capital expenditure and their installation costs are higher.
  2. Reliability — Because many centralized UPS systems facilitate N+1 parallel redundancy, they tend to provide enhanced reliability over distributed power supplies. These larger systems tend to also have a longer lifespan. However, one potential drawback is that some centralized units are vulnerable to a single point-of-failure. If all resources are concentrated in one power system and damage occurs to that source, all connected equipment will be impacted. Because distributed UPSs have more components, they pose a greater likelihood of failing, necessitating additional monitoring and maintenance to prevent downtime.
  3. Flexibility — Across today’s ever-changing business landscape, it is not uncommon for power requirements to rapidly increase. When your uninterrupted power supply is capable of accommodating these changes, it can be extremely beneficial. This is the case with centralized UPSs, most of which provide simple, cost-effective scalability through the addition of power modules. On the other hand, if you outgrow the capacity of your decentralized system, you must purchase additional UPSs to support load demands. Yet distributed UPSs do offer flexibility in the event they need to be moved or relocated to a new facility.
  4. Space — Space is a factor that can be either a benefit or a detriment for both types of UPS systems, depending on your specific environment. While a centralized installation may require a separate room or location in order to house the larger UPS footprint and optional external battery cabinets, decentralized deployments require sufficient space alongside the protected equipment or within the rack where each UPS is placed.
  5. Installation — Because most decentralized UPS systems provide easy plug-and-play installation using existing wall sockets, they typically do not require rewiring for installation. Centralized UPSs, on the other hand, usually necessitate an electrician and/or support personnel due to specialized electrical outlets and three-phase power requirements.
  6. Service — Organizations that lack the time or manpower to monitor, manage and service multiple units will likely appreciate a centralized power system, which streamlines maintenance and repairs and reduces potential points of failure. Decentralized designs typically require more time and focus in order to stay on top of maintenance and battery replacement. However, a great option for either UPS type is to engage with a third-party service provider who can oversee all maintenance tasks on your behalf.

Discover the Benefits of Unified Power

Because every business is different, the type of UPS system you choose ― whether centralized or decentralized ― should match your unique needs and uptime requirements. It is also important to consider the complexities of your facility’s electrical system and your in-house capabilities when it comes to managing and maintaining the power system.

Unified Power is a partner you can trust to help meet all of your critical power equipment and service needs. From UPS and generator sales, to turnkey electrical solutions, to maintenance and repair of all major manufacturers’ equipment, Unified Power delivers unparalleled support on a nationwide scale. We can also custom-tailor power solutions and services to meet the individual needs of your business.

For additional information about our products and world-class services designed to optimize the reliability and performance of your critical power systems, please contact us today.

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