A UK Energy Certificate Compliance Guide
In our experience supporting UK public sector and commercial property portfolios, the most common compliance question we receive is: “Do we need an EPC, a DEC, or both?”
Energy certificates are not interchangeable. Each rates building energy performance but applies in different circumstances and carries different legal obligations under the Energy Performance of Buildings (England and Wales) Regulations 2012, MEES (Minimum Energy Efficiency Standards), and ongoing UK Government EPC reform.
This guide, written by a TEAM Energy’s compliance specialist, explains the full UK regulatory landscape for organisations managing buildings.
Prefer to watch first? This short overview video introduces what this guide covers and who it’s designed for, helping UK building owners, landlords, and public sector estates quickly understand whether their property requires an EPC, a DEC, or both.
Quick Answer: EPC vs DEC
- An EPC (Energy Performance Certificate) is required when a building is constructed, sold or rented. It is valid for 10 years.
- A DEC (Display Energy Certificate) is required for public buildings over 250 m² accessed by the public and must be displayed at all times.
- Both rate buildings A-G but measure different things: EPC = asset rating (design); DEC = operational rating (actual usage).
EPC vs DEC: Full Comparison Table
| Criteria | EPC (Energy Performance Certificate) | DEC (Display Energy Certificate) |
| What is it? | Measures the energy efficiency of a building based on its design, including insulation in walls and roofs, and the efficiency of services such as lighting, heating, and mechanical ventilation. This is known as an Asset Rating. | Measures the actual energy usage of a building based on annual consumption. This is known as an Operational Rating. |
| Who is it applicable to? | All buildings when they are constructed, sold, or rented. Applies to both commercial and domestic properties. | Legally required for buildings over 250 m² that receive public sector funding and are accessed by the public (e.g. local authority offices, NHS buildings, schools, libraries). |
| Format | Certificate showing the building’s energy efficiency and carbon emissions as an Asset Rating from A (very efficient) to G (very inefficient). Accompanied by a Recommendation Report suggesting fabric or heating improvements that would improve the rating. | Certificate showing the Operational Rating from A (lowest energy consumption) to G (highest energy consumption), alongside historical Operational Ratings. Must be clearly displayed in a prominent location at all times and accompanied by a valid Recommendation Report containing energy-saving recommendations from the site survey. |
| Who is responsible? | The builder or person responsible for the construction must provide the new owner with the certificate. Thereafter, responsibility transfers to the building owner or landlord. | The public authority, relevant institution, or building occupier is responsible for obtaining and displaying a DEC for each affected building. |
| When is it required? | An EPC is required when a building is constructed, sold, or rented. A new EPC is required after major renovations. A valid EPC must be available to any prospective buyer or tenant. | A DEC is required at all times for in-scope public buildings. Buildings over 1,000 m² must renew their DEC annually. Buildings between 250 m² and 1,000 m² require renewal every 10 years. |
| Validity period | 10 years (unless major renovations require an updated certificate). | 1 year (buildings over 1,000 m²) or 10 years (buildings 250 m²–1,000 m²). Recommendation Reports are valid for 7 years (larger buildings) and 10 years (smaller buildings). |
| Minimum Energy Efficiency Standard (MEES) | Applies. Non-domestic properties must currently meet a minimum EPC Rating of E to be lawfully let. In its interim response of 18 June 2026, the UK Government confirmed a revised, targeted approach: from 2031, all privately rented non-domestic buildings over 1,000 m² in England and Wales must reach EPC B, where cost-effective. The previously proposed interim EPC C milestone for 2027 will not be taken forward. Buildings below 1,000 m² will continue to be subject to the existing EPC E minimum standard, with no set deadline for going beyond this level. Existing flexibility mechanisms, including the seven-year payback test and exemptions remain in place. The new EPC B standard will only take effect following the successful passage of secondary legislation through Parliament. | Not applicable. DECs measure operational performance and are not subject to MEES. |
| Issuing body | Issued by an accredited Non-Domestic Energy Assessor (NDEA) for commercial properties, or a Domestic Energy Assessor (DEA) for domestic properties. | Issued by an accredited DEC Assessor registered with an approved accreditation scheme. |
| Latest reform context | Subject to ongoing UK Government EPC reform consultation (Energy Performance of Buildings framework reform), which may change methodology, validity periods, and minimum standards. | Largely unchanged since introduction in 2008; not currently in scope of EPC reform consultation. |
| Introduced | 2008 (Energy Performance of Buildings Regulations). | 2008 (Energy Performance of Buildings Regulations). |
EPCs apply across both commercial and domestic property, for an in-depth overview of commercial obligations, see our commercial energy performance explained guide.
Penalties for Non-Compliance
DEC (Display Energy Certificate)
A £500 fine applies for non-display of a valid DEC. A £1,000 fine applies for failing to have a valid Recommendation Report available on request.
EPC (Energy Performance Certificate):
- £500 to £5,000 for failing to make an EPC available at sale or let.
- Under MEES, additional financial penalties of up to £150,000 per property apply for letting sub-standard non-domestic buildings.
Note: Penalty levels are reviewed periodically by UK Government. Always refer to the latest Government guidance or contact our Compliance team for verified, current obligations.
For the most current UK Government position, see the Department for Energy Security and Net Zero’s interim response on Minimum Energy Efficiency Standards (MEES) for the non-domestic Private Rented Sector, published on GOV.UK.
In Our Experience
Across our work supporting UK public sector estates, NHS Trusts, local authorities and commercial portfolios, the three most common compliance failures we see are:
1. Public bodies over 250 m² without a displayed DEC.
2. Commercial landlords renting properties with EPC ratings F or G, in breach of MEES.
3. Buildings undergoing refurbishment without re-issuing an EPC, leaving outdated ratings in place.
We help organisations avoid these risks through structured assessments and accredited delivery. These compliance gaps are common across UK estates, our insights and guidance hub publishes regular educational content on EPC, DEC, MEES, ESOS, and SECR obligations.
Frequently Asked Questions
What is the difference between an EPC and a DEC?
An EPC rates the designed energy efficiency of a building (asset rating). A DEC rates the actual energy use of a building (operational rating).
Do I need both an EPC and a DEC?
Public sector buildings over 250 m² typically need both.
How long is an EPC or DEC valid?
EPCs are valid for 10 years. DECs are valid 12 months for buildings over 1,000 m² and 10 years for buildings 250 m²–1,000 m².
Can I let a property without an EPC?
No. It is illegal in England and Wales to let a property without a valid EPC and meeting MEES standards.
For a deeper look at how DECs are calculated and displayed in the public sector, see our Display Energy Certificates (DECs) Explained guide.
Related TEAM Energy Services
If your organisation requires support with EPC or DEC compliance, our accredited assessment teams can help:
Written by Tim Holman – Head of Consultancy, MSc, MEng, CEng, MEI
Tim directs TEAM’s consultancy practice, applying 25+ years in strategy, audits, metering, and compliance to deliver robust, audit‑ready results for customers. A Chartered Energy Engineer and Member of the Energy Institute, Tim holds an MSc in Energy Conservation and the Environment from Cranfield University and an MEng in Mechanical Engineering from the University of Salford.