Commercial EPCs Explained: The Process of Production, Interpretation, and Improvement
Published: 30/04/2025
What is a Commercial EPC?
A Commercial Energy Performance Certificate (EPC) assesses and displays the energy efficiency of a commercial building, rated from A (most efficient) to G (least efficient). It is a legal requirement for most commercial property transactions to provide information to prospective buyers and tenants.
EPCs are regulated under the Minimum Energy Efficiency Standards (MEES), which require an EPC when:
- The property is being rented out or sold.
- Construction is completed on a new commercial building.
- The building layout changes, creating new separate units with fixed heating, air conditioning, or ventilation systems.
Levels of Commercial EPCs
Commercial EPCs are classified into three levels based on building complexity:
Level 3 – Simple Buildings
Small, simple buildings with “frequently occurring characteristics”, which include features such as standard forms of construction, heating systems less than 100kW, natural ventilation, and comfort cooling systems less than 12kW.
Examples: small offices and retail units.
Level 4 – More Complex & New Builds
Purpose-built buildings with heating systems greater than 100kW, cooling systems greater than 12kW and any building without “frequently occurring characteristics.” All new buildings are likely to be classed as Level 4 or higher.
Examples: Large offices and retail spaces.
Level 5 – Highly Complex Buildings
This is for larger buildings that are complex in design and shape, that might include features such as atriums and complex building services installations.
Examples: Airports, shopping centres, and skyscrapers.
How is a Commercial EPC produced?
A commercial EPC is produced by a government-accredited Non-Domestic Energy Assessor (NDEA). The assessor evaluates the building's energy efficiency and carbon emissions and uses specialised software to calculate an energy rating and generate the certificate.
The assessment is non-invasive, meaning no drilling or intrusive investigations, but the assessor will require full access to the building to take measurements and gather data.
Key information collected includes:
- Occupancy status
- Identification of the different zones of the building and their dimensions
- The activities are conducted within the zones. This could include retail space, office space, warehousing, storage, etc
- Heating, cooling & ventilation systems
- Lighting & controls
- Electrical & power systems
- Building structure, glazing & insulation
The EPC score is then determined by factors like building systems, age, construction, and renewable energy use. Once completed, the certificate is published on the publicly accessible government register: Find an Energy Certificate.
Commercial EPC Rating Scale (A–G)
A Commercial Energy Performance Certificate (EPC) rates buildings on a scale from A (most efficient) to G (least efficient), indicating their energy performance and environmental impact.
Understanding the Ratings:
- A – The highest rating, indicating excellent energy performance with low carbon emissions and minimal running costs. These buildings often incorporate advanced insulation, renewable energy sources, and high-efficiency heating and cooling systems.
- B–C – Above-average efficiency, with effective energy-saving measures in place. Buildings at this level benefit from modern heating, ventilation, and lighting systems, making them more cost-effective to operate.
- D–E – Mid-range efficiency. These buildings meet the minimum legal standards but may still have outdated systems or insulation. Improvements could help reduce energy costs and enhance compliance with future regulations.
- F–G – Poor energy performance, with high running costs and carbon emissions. Buildings in these categories require significant upgrades to meet MEES regulations.
Since April 2023, all commercial properties under new and existing leases must achieve at least an E rating to comply with MEES. Landlords with F or G-rated properties must make improvements or register for an exemption to legally rent out their buildings.
Read our article on MEES to learn about its applicability to your property, qualifying exemptions, and proposed target changes up to 2030.
Improving your EPC rating: Practical Solutions
In addition to the EPC rating, an EPC includes recommendations for improving energy efficiency, from simple upgrades to major renovations.
Building fabric improvements:
- Improved insulation for external walls and roofs.
- Double or triple glazing installation.
- Air tightness improvements (e.g. sealing gaps and adventitious cracks in the building fabric).
Building services upgrades:
- LED lighting with smart controls & occupancy sensors.
- Efficient heating, ventilation, and air conditioning systems (e.g., VRF units) that regulate temperature, humidity, and air quality.
- Demand-driven ventilation systems.
- Solar panel installation.
EPCs are valid for 10 years, meaning that a new EPC is not required every time a property is let or sold, provided it is no more than 10 years old. However, achieving a higher rating now helps future-proof your property against evolving regulations and market trends.
In an increasingly environmentally conscious market, energy efficiency is more than just compliance, it’s a competitive advantage.
How Harris Associates Can Help
At Harris Associates, we support commercial landlords in meeting Minimum Energy Efficiency Standards (MEES), enhancing sustainability, and unlocking greater long-term value from their properties.
Whether you require a commercial EPC, need to improve your building's energy performance rating, or are looking to implement a long-term sustainability strategy, our team of experienced project managers, building surveyors, and cost consultants is equipped to guide you through every stage.
From compliance to carbon reduction, we deliver tailored advice and practical solutions that ensure your portfolio remains efficient, legally compliant, and resilient to future regulation.
Contact us today to learn how we can help you optimise your assets and meet your environmental and commercial objectives.
Article By Lewis Denbow