Lighting, both indoor and outdoor, is one of the biggest energy drains in office environments: it accounts for nearly 28 percent of total office energy consumption. According to the US Department of Energy (DOE), 22 percent of the total electricity used in the US goes to lighting up our lives. This adds up to about $55 billion worth of electricity, roughly the equivalent to the output of 100 large power plants emitting 450 million tons of carbon dioxide and 3 million tons of smog-generating nitrogen oxides and sulfur dioxide yearly.
T12 bulbs—by far the most popular office illuminators around—are at least 20 percent less efficient than new bulbs like T8s and T5s. Incandescent bulbs found in many commercial buildings produce only 20 percent light and 80 percent heat with the energy they consume. The heat given off by these lights compounds energy consumption problems by heating indoor spaces, increasing the need for fans and air conditioners.
In the US, there are upwards of 100 million exit signs running 24/7, typically using energy-wasting incandescent technology that consumes an estimated 30-35 billion kilowatt-hours (kWh) of electricity annually. Conventional incandescent exit sign bulbs, which last about 2.8 months (when operated 24 hours/day) use 350 kWh, cost $28 per year to run, and create 574 pounds of CO2 pollution. In contrast, CFL exit signs (lasting 10.8 months), use 140 kWh, cost $11 to run each year, and produce about 230 pounds of CO2 emissions.
Another cost factor involved in office lighting: employee efficiency. The wrong amount or kind of light can result in eyestrain, glare, and headaches, which in turn can decrease employee productivity. Switching to high performance lighting can improve employee efficiency by 6.7 percent.
Office lighting retrofits can be relatively inexpensive with quick return on investment (five years or less). A lighting upgrade in one Pacific Northwest National Laboratory building resulted in annual electricity savings of $6,167 and 154,163 kilowatt-hours of energy.
Questions to get you started…
- Have you replaced inefficient bulbs with CFLs, LEDs, T8s?
- Do you have motion sensors or daylight sensors that turn lights off overnight?
- Has your office procured power strips for lighting and other electronics?
- Does your building have an energy management system to track energy use and reduce energy costs?
- ENERGY STAR - Energy Calculator for Small Businesses
- US Department of Energy - Energy Efficiency and Renewable Energy: Lighting
- Energy Guide’s Efficiency FastTrack helps businesses identify energy-saving opportunities.
- Cool Companies Find companies that have agreed to conserve energy and cut greenhouse gas emissions.
- Florida Power and Light - Lighting Incentives: Turn On the Savings
- Public Works and Government Services Canada - An Architect's Guide for Sustainable Design of Office Buildings: Reducing Lighting Energy
- CNET News.com - Cheaper LEDs to light a green path?
- NEMA - Next Generation Lighting
- Earth 911 - 8 Ways to Green Your Office: Switch out certain light bulbs and monitoring lighting usage
- GreenBiz.com - Grants Help Publishers Cut Energy Costs, Pollution
- ENERGY STAR - Exit Signs
- ENERGY STAR - Save Energy, Money and Prevent Pollution with Light-Emitting Diode (LED) Exit Signs
- ENERGY STAR - Simple, Sure Energy Savers
- Transwestern - Building Sustainability for our Time: Green Buildings Reduce Labor Costs Page 2
- US Department of Energy - Economics of Energy Effective Lighting for Offices
- US Department of Energy - ENERGY STAR® Designates High-Efficiency Buildings: Pacific Northwest National Laboratory