Improving Power Usage Effectiveness (PUE)

June 9, 2014 Tripp Lite

What is Power Usage Effectiveness?

Power Usage Effectiveness (PUE) is the ratio of total energy employed at a data center or network facility vs. the total energy used strictly by IT equipment. Essentially, it measures how efficiently power is utilized in the data center. This metric is ideally used as the basis to make the data center more efficient.

How to Measure PUE

PUE = Total Facility Energy / IT Equipment Energy

Given the equation above, we can infer that two values are needed to determine PUE: Total Facility Energy and IT Equipment Energy. To calculate each, you must make a comprehensive list of all energy-consuming equipment and then categorize each item as part of either a.) the IT load or b.) the physical infrastructure. Once your list is categorized properly, you can use the two values to solve for your data center’s power usage effectiveness.

Improving PUE

An ideal PUE is 1, or 100% efficiency. The lower (or closer to 1) the PUE, the more efficient the data center. The more efficient the data center, the lower the total cost of operation (TCO).

There are a number of ways to improve PUE, but you should start by identifying the low-hanging fruit. For example, cooling is often the biggest offender in low-efficiency data centers. You can reduce the power required for cooling by taking some simple steps to increase airflow:

  1. Organize cables
    Bulky cabling can obstruct airflow, especially if it’s disorganized and tangled. Using the right type of rack with the appropriate cable management will allow air to flow freely and cool equipment properly.
  2. Install Blanking Panels
    Blanking Panels can help force cold air through servers and other equipment. They help define the path of cold air so that less of it is wasted and more of it is distributed directly to equipment.
  3. Isolate and Remove Hot Air
    Make sure that hot air has a way out. If the exit path isn’t well-defined or isolated, there is greater risk of the heated air recirculating into the data center. Since heat rises, the best exit path is through a raised ceiling panel or roof-mounted thermal duct and onward to the facility’s built-in exhaust system.

Once you’ve taken these basic steps, you may want to look at other ways to improve PUE. As data centers are complex environments with a lot of moving parts, there are numerous places to look for inefficiencies. Consult with our Technical Support Team to determine other methods for increasing efficiency.


    From desktop to critical infrastructure, Tripp Lite products and solutions power and connect the computers, networking equipment and electronic devices that form the foundation of our digital world. Headquartered in Chicago since 1922, Tripp Lite has offices and partners worldwide.

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