25% of the total electricity used by all commercial buildings in the US is consumed by office buildings. When buying any new office equipment, look for Energy Star certified machines. This will make a huge difference in the amount of electricity that is used to run your office. For example, an Energy Star certified computer is going to be 52% more efficient than a standard one. Laptops also use a lot less energy than desktops, so consider whether this is a viable option for your office. Energy efficient machines are also going to have stand by options that will power down or go into sleep mode to conserve energy when not in use. Once the office is closing for the day, make sure that all equipment is powered off.