The baseline period in M&V must be representative of typical operating conditions before the ECM, capturing energy plus explanatory variables (weather, occupancy, production), and typically covers a full 12-month cycle for buildings.

A valid baseline period must span a complete seasonal cycle (12 months for HVAC-driven facilities) and reflect typical operations (not a period of partial refurbishment). It must capture energy, degree-days, occupancy and production where applicable, with conditions exhaustively documented. A weak baseline produces indefensible savings and is the single most common cause of disputes in audits or litigation.

If the baseline year was atypical (COVID, plant shutdown), flag it early and seek owner approval before locking the M&V Plan.