Back to glossary
Energy Audit
Key takeaways
- An energy audit is a structured review of how a business uses energy across its sites and processes.
- It produces a prioritised list of cost-effective savings, often as the start of an energy reduction strategy.
- Large UK undertakings are required to audit periodically under ESOS; smaller businesses do it voluntarily for the savings.
What is an energy audit?
An energy audit is a systematic assessment of how a business consumes energy — looking at electricity, gas, heat, transport fuel and process energy — and identifying where savings are possible.
Audits typically combine bill analysis, half-hourly consumption data, on-site inspection, and benchmarking. The output is a prioritised list of measures, each with estimated cost, savings and payback.
ESOS in the UK
The Energy Savings Opportunity Scheme (ESOS) requires large UK undertakings to assess total energy use and energy-saving opportunities at least every four years.
Compliance is overseen by the Environment Agency (England) and equivalents in the devolved nations.
Even where ESOS doesn’t apply, voluntary audits typically pay back quickly through metering improvements, lighting and controls.
What a useful audit covers
- Bill and tariff review (including any pass-through charges).
- Half-hourly consumption profile by site, including peak and baseload behaviour.
- Heating, ventilation, lighting, motors and processes.
- Opportunities for load shifting, controls, and renewable on-site generation.
