Of all commercial building expenditures, energy is probably the largest. Office buildings use approximately 19 percent of all energy consumed in the US, a number that’s proportionately higher than any other country in the world. In fact, energy use can account for over 30 percent of a company's operating budget, while adding 20 percent to the nation's total greenhouse gas emissions.
Most of the energy needed by offices gets used for electricity, heating and cooling, and other electronic equipment. Offices consume more electricity and natural gas than any other building type in the commercial sector. Of all these energy types, electricity use by commercial businesses has increased the most (nearly 40 percent) in the last several decades. 
Heating, ventilating, and air conditioning (HVAC) systems account for between 40 percent and 60 percent of total energy use (all forms of energy) in the commercial sector, making it the largest business energy drain.
But businesses also use a significant amount of energy to transport their employees and their goods across the country and around the globe. Although air travel isn’t the most common mode of business transportation (only about 16 percent of business trips are by plane; 81 percent by car), it generates the greatest amount of greenhouse gas emissions. In fact, global air travel (including business-related flying) accounts for approximately 7 percent of worldwide carbon emissions. Business travelers log a combined 240 billion passenger-miles in the sky each year.
Electricity alone accounts for 70 percent of all commercial power consumption with lighting being the largest office electricity drain. This is due in large part to the outdated lighting technology employed by most businesses—old-style T12 style bulbs that consume 20 percent more energy than new varieties likeT8s and T5s. Inefficient exit signs further compound this problem. There are upwards of 100 million exit signs in the US running 24/7, typically using energy-wasting incandescent technology that consumes an estimated 30-35 billion kilowatt-hours (kWh) of electricity annually.
Questions to get you started...
- Does your business have an energy management system to track energy use and reduce energy costs?
- Does your company participate in the ENERGY STAR program? If so, what is its current rating?
- Do you use energy efficient light fixtures like CFLs, LEDs, and T8s?
- Have you installed motion sensors or daylight sensors that turn lights off over night?
- Have you procured power strips as an effort to cut energy use?
- Are employees actively encouraged to turn off computers, monitors, copiers, and printers overnight?
- Is energy efficiency factored into your procurement policy?
- Have you procured ENERGY STAR appliances and electronics?
- Energy Information Administration - Emissions of Greenhouse Gases Report: Commercial Sector
- EnergyGuide - BusinessAnalyzer - A self-guided energy-efficiency analysis tool for small- and mid-sized businesses.
- ENERGY STAR - Portfolio Manager - An interactive tool to track and measure energy and water use across a business’ entire portfolio of buildings.
- World Resources Institute - WRI's Green Office Guide
- World Business Council for Sustainable Development - Energy Efficiency in Buildings: Alarming Energy Growth Page 11
- ENERGY STAR - Commercial Real Estate: An Overview of Energy Use and Energy Efficiency Opportunities
- Energy Efficiency Administration - Commercial Buildings: 1992 Consumption & Expenditures
- Energy Efficiency Administration - Energy Efficiency: Table 2. Energy Use, and Related Carbon Emissions, Commercial
- US Department of Energy - Choose Building Components: Heating and Cooling Systems
- ENERGY STAR - Heating and Cooling System Upgrades
- US Bureau of Travel Statistics - National Household Travel Survey: US Business Travel
- United Nations Atlas of the Oceans - Air travel pollution
- GreenBiz.com - Greening Your Company's Business Travel
- US Energy Information Administration - Office Buildings - How do they use electricity?
- Ideal Bite - Thought you were making a difference by saving energy at home?
- ENERGY STAR - Exit Signs