Plug Loads


Plug loads account for 33% of U.S. commercial building electricity consumption. What is a plug load? It’s simple. Plug loads come from any devices that plug into a building’s electrical system, such as computers, lamps, and printers. Why are plug loads important? Electricity use associated with plug loads is on the rise, and plug loads in commercial buildings are now one of the fastest growing end uses of energy.

Energy efficiency efforts in commercial buildings historically have targeted lighting, heating and cooling systems, water heaters and major appliances. Today, the typical business worker also uses an ever-growing suite of electronic devices, all drawing from the power grid and running up the utility bill.


The good news is that plug loads can be managed through low- and no-cost measures that are relatively straightforward to implement. Below is a list of tasks that shows how simple changes can you’re your business save energy and cut costs.

What are the biggest contributors to plug loads? 

The biggest culprits are typically computers, monitors, imaging equipment, computer peripherals, and server rooms. Other equipment that draws additional power includes task lights, space heaters and portable fans, projectors, televisions, vending machines, kitchen equipment, cell phone chargers.  The table below shows the energy consumption and associated average annual operating cost.  



Average Electricity Usage of Common Office Items

What can you do about it?

Install a smart powerstrip.

Smart powerstrips are easy-to-use and acts as a central way to turn off all your devices at once. Use them in an office kitchen for small appliances or for computer equipment. There are different kinds of smart powerstrips, including those with timers, and surge protection.  

Convert existing servers to “virtual servers.”

Server virtualization offers a way to consolidate servers by allowing you to run multiple different workloads on one physical host server. A "virtual server" is a software implementation that executes programs like a real server. In addition, virtualization speeds up disaster recovery efforts because virtual servers can restart applications much more rapidly than physical servers. 

Add a plug load occupancy sensors to individual workstations.

Plug load occupancy sensors can dramatically cut costs with energy savings of up to 50%. This system consists of plug load occupancy sensors controlling powerstrips. They allow the worker to choose which equipment is controlled by occupancy, and which would be left on throughout the day. Plug load occupancy sensors are relatively inexpensive, easy to install and maintain, and are likely to pay for themselves in a year or less. 

Use computer power management software.

Computer power management (CPM) features automatically place computers into a low-power "sleep mode" after a period of inactivity. Simply touching the mouse or keyboard "wakes" the computer in seconds. Your network administrator can activate these settings quickly and easily across your entire network and save up to $50 per computer annually.

Install a vending miser to existing vending machines.

A vending miser consists of a motion sensor and the miser itself. The miser works by making the vending machine more energy efficient. If no one is near the vending machine for 15 minutes and the compressor is not running, the vending miser will shut off the machine. The vending miser also measures ambient room temperature. If the room is very warm, the vending miser will more often send power to the machine than if the machine is in a cold room. The estimated savings for each vending machine with a miser is approximately $192 per year.