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Energy & carbon

Energy Performance Certificates (EPC) Explained

An Energy Performance Certificate (EPC) rates a building's energy efficiency and is required at key transaction points. This guide explains what an EPC is, when you need one, and what the rating means.

In short

An Energy Performance Certificate (EPC) rates a building's energy efficiency from A (most efficient) to G (least efficient). It is required when most buildings are built, sold, or let, is valid for ten years, and includes recommendations for improving efficiency.

When an EPC is required

An EPC is generally required whenever a building is constructed, sold, or let, with some exemptions (for example certain listed buildings and temporary structures). For commercial property, the EPC is produced by an accredited assessor and must be made available to prospective buyers or tenants. The certificate shows the asset rating on the A–G scale and lists recommended measures to improve performance.

MEES and minimum standards

EPC ratings have real commercial consequences through the Minimum Energy Efficiency Standards (MEES). For most commercial lettings in England and Wales, it is unlawful to let a property below a minimum EPC rating (currently E, with tighter standards proposed over time). This makes the EPC rating a factor in whether a building can be let at all, driving investment in efficiency improvements to maintain lettability — a key concern for landlords and asset managers.

Improving an EPC rating

The EPC's recommendation report identifies measures to improve the rating — better lighting and controls, heating and cooling upgrades, insulation, and improved metering and management. Realising these improvements depends on understanding the building's current systems and how they are operated and maintained. Accurate documentation of plant, controls, and energy data underpins both the assessment and the improvement works that follow, helping target the changes that will most improve the rating.

Frequently asked questions

Target efficiency improvements with better data

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