A lighting energy audit is a detailed assessment of energy use by lighting systems in buildings, aimed at identifying opportunities to improve energy efficiency. This type of audit is a key element in efforts to improve sustainability and reduce operating costs. The main stages and methods used in a lighting energy audit are described below.
Preparing for the audit
Before starting a lighting energy audit, it is essential to collect the necessary data and documentation on the existing lighting systems. This includes building plans, technical specifications for lighting equipment, electricity bills, and any previous analyses and reports on energy consumption.
Lighting system inventory and analysis
At this stage, the auditors carry out a detailed inventory of all light sources at the site. They document the types of luminaires, their quantity, power ratings, operating time and locations within the building. Identifying controls and sensors that may affect energy consumption is also an important part of the assessment.
Lighting efficiency analysis
Once the data have been collected, the lighting system is assessed for efficiency. This includes evaluating power factor (PF), luminous efficacy (lm/W) and lighting quality, for example the colour rendering index (CRI). The assessment also considers the ergonomic quality of the lighting and its effect on the comfort of building users.
Identifying improvement opportunities
Based on the analysis, the auditors identify areas where energy savings are possible. Recommended measures may include replacing outdated light sources with more efficient alternatives such as LEDs, installing automatic lighting control systems such as motion and occupancy sensors, and optimising the settings of existing systems.
Reporting and recommendations
The final stage of the audit is the preparation of a detailed report presenting measurement results, analyses and recommendations for measures to improve energy efficiency. The report also includes a cost–benefit analysis of the proposed measures, enabling the company to make an informed decision about investments in upgrading its lighting system.
Lighting energy audit vs company energy audit
A lighting energy audit is an important part of a broader company energy audit, which is mandatory for large companies in many countries, including EU Member States. A mandatory energy audit covers the energy consumption of all systems and processes across the company, with lighting accounting for a significant share of that consumption. Improving lighting energy efficiency can have a substantial effect on the company’s overall energy balance, helping to reduce operating costs and CO₂ emissions.
Carrying out a lighting energy audit as part of a mandatory company energy audit enables a comprehensive assessment of energy-saving potential and the implementation of coherent energy management strategies. A lighting energy audit provides detailed data needed to meet legal requirements relating to energy efficiency and energy-consumption reporting, which is important for regulatory compliance and for supporting the company’s reputation as an environmentally responsible business.
