Why Plug Loads Matter

The building industry has made significant progress with integrating energy conservation into standard operating procedures. Advancements in building systems, envelopes, and controls have led to reduced energy use, more sustainable environments, and a healthier bottom line. The benefits are well documented.

With this backdrop, the current state of plug loads in commercial office buildings, particularly in the Washington, DC market, remains a curious outlier. Plug loads refer to the power available to the wall outlets or systems furniture plugs in a general office environment. It is a measure of the power needed to run computers, printers, copiers, task lighting, and other office equipment that requires electricity to operate. Most DC-area buildings are designed with 4-5 w/SF to service plug loads, plus another 1 w/SF for lighting.

So why do plug loads matter? Because, as the conservation trend has taught us, bigger is not always better. There are huge potential energy conservation opportunities and construction and operational cost savings that can be realized by simply right-sizing systems.

Plug loads not only provide power to devices in a building, they also deliver the waste heat generated as a byproduct of those devices. Early conversations regarding how to deal with cooling waste heat are an essential part of planning for cooling requirements based on existing or expected plug loads.

This is just the beginning of the plug load conversation. In future posts, we will examine just how much plug loads could be safely reduced in standard office buildings, as well as strategies for and the ramifications of achieving these savings.


As President and Senior Principal of GHT, Paul O’Brien, PE, LEED AP ID+C oversees GHT’s delivery of high quality services from start to finish. Through constant communication with clients and staff, he validates project goals and ensures the design of sustainable MEP engineering solutions that balance comfort, efficiency, and purpose.