What Your Display Energy Certificate (DEC) Is Really Telling You

July 1, 2026
Nero Energy
Energy

What Your Display Energy Certificate (DEC) Is Really Telling You

If your building is open to the public, your energy performance may already be on display.

A Display Energy Certificate (DEC) is a legal requirement for many public buildings over 250m² that are frequently visited by the public. Unlike an EPC, which predicts how efficiently a building should perform, a DEC measures how much energy your building actually used over the previous 12 months. It provides a real-world picture of operational performance and assigns a rating from A (most efficient) to G (least efficient).

For schools, colleges, NHS estates, local authorities and other public sector organisations, a DEC is more than a compliance document, it can be a valuable starting point for reducing energy costs and progressing towards net zero.

Understanding Your DEC Rating

Your DEC rating provides an immediate indication of your building’s operational efficiency:

A lower rating doesn’t necessarily mean your building is poorly managed. Many public buildings operate from ageing estates with outdated heating systems, limited insulation or inefficient lighting. However, it does highlight where investment can make the greatest difference.

Don't Overlook the Advisory Report

Every DEC is accompanied by an Advisory Report, which is often underutilised despite containing practical recommendations to improve energy performance.

These recommendations can include:

Reviewing your DEC alongside its Advisory Report can quickly identify where energy, carbon and financial savings are achievable.

Turning Compliance into Opportunity

For many organisations, a DEC is the first step in developing a wider decarbonisation strategy.

By understanding how your building performs today, you can begin planning improvements that reduce operating costs, improve occupant comfort and support your organisation’s sustainability objectives.

Many of these improvements may also be eligible for grant funding or low-interest finance, making it possible to accelerate decarbonisation without placing the full cost burden on your organisation.

How Nero Energy Can Help

At Nero Energy, we work with public sector organisations across the UK to turn DEC recommendations into practical, funded projects.

Our team can support you with:

Whether your building is already performing well or has significant room for improvement, we can help you develop a clear roadmap towards lower energy costs and net zero.

If you haven’t reviewed your Display Energy Certificate recently, now is a good time to do so.