Energy audit (commercial/condominium)

An energy audit (commercial/condominium) is an in-depth technical study that measures, explains, and prioritizes potential energy savings for a building or complex (offices, shops, housing). Going beyond a standard Energy Performance Certificate (EPC), the audit provides data, calculations, and figures: it establishes a baseline, simulates improvement scenarios (building envelope, HVAC, building management systems, renewable energy sources), estimates savings (kWh, CO₂, €), and proposes a phased approach to the work that is compatible with occupancy. The goal: to make informed decisions based on solid data, reduce operating expenses, and improve comfort.

Energy audit: definition and operational process

A structured audit generally includes: site visits (measurements, photos, interviews), data collection (plans, consumption history, contracts), sub-metering or operation of the BMS/EMS, then modeling (building and systems) to understand losses and uses.

It produces a standardized baseline (weather/occupancy), targeted diagnostics (building envelope, HVAC, DHW, ventilation, lighting, auxiliary systems), and scenarios ranging from no/low-cost adjustments to major renovations (insulation, generator replacement, PV/solar, heat recovery). For each action: estimated CAPEX, kWh/€ savings, CO₂ avoided, impacts on comfort (including summer comfort), risks, and prerequisites. The audit concludes with a roadmap (priorities, timeline, potential subsidies such as Energy Savings Certificates (CEE), integration with the Energy Performance Contract/PPE), ready to be presented at the General Meeting, Executive Committee, or Investment Committee.

Advantages, limitations and points to consider in energy audits

Interests

• Informed decision: savings quantified and ranked by ROI.
• Less risk: coordinated work (building envelope ↔ HVAC ↔ BMS) and phasing in an occupied site.
• Comfort & IAQ: settings and investments that improve usage, not just kWh.
• Access to aid: framework for Energy Savings Certificates (CEE), financing applications, standard Energy Performance Contracts (CPE).

Boundaries

• Cost and timeframe of the study to be included in the schedule.
• Data-dependent quality (plans, counts, cleaning history).
• Recommendations should be updated if energy usage or prices change significantly.

Points to consider

• Measurement before decision: check ΔT, flow rates, hourly drifts, DHW leaks.
• Priority to the logical order: sobriety/adjustments → efficiency → RES.
• Summer comfort: integrate sun protection, thermal inertia, night ventilation.
• Governance: readable deliverables (summary of leaders + technical annexes).
• Post-audit follow-up: indicators, milestones, and annual review of the action plan.

Anecdote — “The diagnosis that calmed Part-Dieu (Lyon)”

In Lyon – Part-Dieu, an office building was experiencing soaring costs and overheated rooms in the summer. The audit identified three solutions that didn't require major renovations: softened water, sequencing morning ventilation cycles, and nighttime ventilation controlled by weather conditions. The result over 12 months: a 12% reduction in electricity consumption, a 9% reduction in heat, and complaints cut in half. Major investments (parapet wall insulation, replacement of heating elements) were phased in the following year, resulting in Energy Savings Certificates (CEE). The moral of the story: a good audit pays off twice—first through adjustments, then through well-chosen improvements.