Measurement and Verification
Core concepts
Measurement and Verification (M&V) establishes that claimed savings actually occurred. The foundational framework is the IPMVP (International Performance Measurement and Verification Protocol), which defines options: Option A (retrofit isolation, key parameters measured), Option B (retrofit isolation, all parameters measured), Option C (whole facility, utility meter), and Option D (calibrated simulation). Savings are computed as baseline energy minus reporting-period energy, adjusted for changes in independent variables such as weather, occupancy, or production.
Traps to watch
A frequent trap is confusing avoided energy use with savings - savings are a counterfactual, not a meter reading. Another is forgetting to adjust the baseline; if production rose 20%, raw consumption comparisons misstate savings. Questions may ask which IPMVP option fits a scenario: whole-building metering with many measures points to Option C; a single chiller retrofit with measured kW and hours points to Option A or B. Also watch for confusion between measurement uncertainty and model uncertainty.
Worked example
Baseline: 1,200,000 kWh at 3,000 heating degree-days. Reporting period: 1,100,000 kWh at 3,300 HDD. Using a simple weather-normalized model with a 200 kWh per HDD coefficient: adjusted baseline = 1,200,000 + 200 × (3,300 − 3,000) = 1,260,000 kWh. Savings = 1,260,000 − 1,100,000 = 160,000 kWh.
Practical guidance
Establish the baseline before implementation, define the measurement boundary, choose the option that balances cost and rigor, and document the regression model, its fit (R²), and its uncertainty.