Evaluating energy performance requires good information on how, when, and where energy is being used. Collecting and tracking this information is necessary for establishing baselines and managing energy use.
The data must be complete and accurate because it will be used for analysis and goal setting. Inventory all energy purchased and generated on-site (electricity, gas, steam, waste fuels) in physical units (kWh, mMBtu, Mcf, lbs of steam, etc.) and on a cost basis. Assemble energy bills, meter readings, and other use data.
Use a Tracking System
A system for tracking performance can range from a simple spreadsheet to detailed databases and IT systems. The following website http://www.energywatcher.com/ offers a lot of great advice as well as a "Free Utility Bill Tracking Spreadsheet" for tracking your energy data.
Once you have your yearly data totals it is recommended that you divide the units by 365 to get your average daily usages. This will be very helpful in setting daily targets for energy reductions. The next step is to install real-time energy monitors so that you can track and monitor on a daily basis.