Before a retrofit: establish an energy and water baseline

1. Fix the boundary and period

Decide whether the study covers a whole building, a cooling system or one floor. Connect every meter to the areas and loads it serves. As a preparation step, collect 12 consecutive months of bills where available to understand seasonality; the project may need a different period or additional data under an appropriate measurement and verification plan.

2. Build a record of actual operation

Bill amounts can change because of tariffs or charges. Separate consumption quantities from costs, and record influential changes rather than treating every decrease as improved efficiency.

• Electricity in kilowatt-hours and water in cubic metres, with reading dates.
• Purchased cooling or other energy supplies in their original units.
• Covered areas, occupancy, operating hours and patterns of use.
• Relevant weather data, faults, leaks and equipment changes.

3. Use an indicator without calling it certification

Hypothetical teaching example: a building uses 240,000 kilowatt-hours over one year within a defined boundary and has a covered area of 2,000 m². Electricity intensity is 120 kWh/m²/year. This is an arithmetic indicator, not proof of efficiency or a green rating. Comparisons require consistent area definitions and included loads.

4. Agree how improvement will be demonstrated

Document the pre-intervention condition, measure scope, meters, data accuracy and treatment of changes in occupancy or weather. Compare post-installation records with an appropriate baseline after justified adjustments. Investigate operations, leaks and meter records when consumption changes unexpectedly, and involve the utility if meter accuracy is in doubt.