Arranging a Display Energy Certificate (DEC) assessment is a legal requirement that should be a straightforward process. However, without the right preparation, it can quickly become drawn out – leading to delayed site visits, repeat data requests, and potential gaps in compliance.
In our experience, most delays don’t come from the assessment itself; they usually stem from missing information or limited access on the day of the visit. Fortunately, these issues are easily avoided if you know what to have ready in advance.
This guide sets out exactly what you need to have in place before a DEC assessor attends your site. By following these steps, you can ensure a streamlined inspection, maintain continuous compliance, and avoid the need for subsequent follow-up requests.
ACI Reports’ accredited DEC assessors support you from initial preparation through to certification, helping you maintain compliance while identifying opportunities to reduce energy costs and emissions.
Understanding Display Energy Certificates (DECs)
A Display Energy Certificate (DEC) measures the actual energy consumption of a building over 12 months. This is a key distinction from an Energy Performance Certificate (EPC), which assesses how energy efficient a building is based on its construction and systems.
DECs are legally required for buildings in England and Wales that:
- Are fully or partially occupied by a public authority
- Are frequently visited by the public
- Have a total operational floor area exceeding 250m²
The DEC certificate gives your building a rating from A (most efficient) to G (least efficient) and must be displayed where visitors can clearly see it. They must also be issued alongside a Recommendation Report, which sets out practical steps to reduce energy consumption and improve overall performance.
Validity Periods
The validity of a DEC certificate depends on the size of the building:
- For buildings with a total useful floor area of more than 1,000m², the DEC is valid for 12 months, while the accompanying Recommendation Report remains valid for 7 years.
- For buildings between 250m² and 1,000m², both the DEC and Recommendation Report are valid for 10 years.
If your DEC has expired, it is important to act promptly. Where we are instructed within a short timeframe, ACI Reports can often continue from the previous certification period, helping you restore compliance quickly and reduce the likelihood of enforcement action.
Appointing an Accredited Energy Assessor
If you are responsible for a building or multiple buildings that fall within the scope of DEC legislation, it is your duty as the occupier to ensure a valid DEC certificate and Recommendation Report is in place at all times (this applies to each of the buildings affected).
A DEC and its accompanying advisory report can only be produced by an accredited energy assessor. This may include a member of your own team, provided they are qualified and registered with an approved accreditation scheme. You can find accredited assessors, including ACI Reports, via the government’s official register.
What Happens During the Visit?
Once instructed, the energy assessor will arrange a suitable time to carry out the assessment. Depending on the building and available data, this may involve a site visit, a desk-based review, or a combination of both. In most cases, at least some level of on-site verification is required.
During the assessment, the assessor will:
- Review energy consumption data for all fuels used over a 12-month period
- Calculate CO₂ emissions relative to the building type and floor area
- Assess key systems, including heating, cooling, lighting and insulation
- Review any on-site energy generation, such as renewable technologies
Following the assessment, the DEC and Recommendation Report are produced and submitted to the national register. The certificate must then be displayed prominently within the building.
What to Prepare in Advance
Preparation plays a significant role in how quickly and smoothly your DEC certificate assessment can be completed. The following areas should be addressed in advance of the visit.
1. Building Information
The DEC assessor will need a clear and accurate understanding of the building’s layout and characteristics. You should provide:
- Scaled floor plans of all applicable buildings
- Confirmed total operational floor area(s)
- Copies of any previous DEC certificates and advisory reports
- Supporting documentation, such as site notes or photographs, where available
- Details of any access restrictions or health and safety concerns
Any existing building documentation should be reviewed before the assessment to ensure it reflects the current state of the building.
2. Occupancy and Operational Profile
Energy consumption data must be considered alongside how the building is used. Be prepared to outline:
- Operating hours, including any seasonal variation
- Typical occupancy levels and usage patterns
- Any significant changes in the past 12 months, such as new equipment, changes in occupancy, or altered operating schedules
This information helps ensure the assessment accurately reflects real-world usage.
3. Energy Consumption Data
A complete and consistent dataset is essential for producing a valid DEC certificate. You will need to provide a continuous 12-month period (365 days) of energy data covering all fuels used within the building, including electricity, gas, oil, district heating / cooling, and biomass or other delivered fuels.
Acceptable formats include meter readings, utility invoices, and delivery or consignment notes. This information may be obtained from several sources, including on-site meters, landlords, managing agents, utility providers, or district energy suppliers. Ensuring there are no gaps or inconsistencies is key to avoiding delays.
4. On-Site Access and Key Contacts
Access to the building(s) and relevant systems is necessary to complete the DEC assessment efficiently. You should:
- Nominate a primary point of contact for the visit
- Ensure access is available to plant rooms, meters, or restricted areas
- Arrange for someone familiar with the building’s systems to be available if required
Where access is limited, additional visits or follow-up requests may be needed, so it’s crucial to prepare as much as possible.
5. Access Common Information Point (CIP)
The assessor may need to access the government’s Common Information Point (CIP) during the assessment. To allow the assessment to proceed without interruption, you should ensure a reliable internet connection is available and confirm that any IT restrictions will not prevent access if your network is used.
Key Tips for DEC Audit Compliance
To ensure your DEC certification stands up to official scrutiny and avoids being flagged during a spot check, keep these audit-ready principles in mind:
- Maintain an Evidence Trail: Keep copies of the original utility invoices or meter readings used for the assessment. Assessors must be able to prove the data matches the 12-month period shown on the DEC certificate.
- Verify Floor Areas: Ensure your floor plans are up to date. If the building has been extended or partitioned since the last DEC, an outdated floor area is one of the most common reasons for audit failure.
- Document Site Specifics: If your building has untypical energy demands (such as a server room or 24-hour security hub), ensure these are documented. This justifies why your building’s energy use might differ from standard benchmarks.
- Standardise Display: By law, the DEC must be at least A3 in size and placed in a prominent location. A small certificate fixed behind a reception desk is a frequent point of non-compliance.
- Synchronise Dates: Ensure the assessment date on your DEC certificate accurately reflects when the site visit or data review took place. Misaligned dates can trigger a "Request for Information" (RFI) from accreditation bodies.
Book Your Next DEC Assessment with ACI Reports
ACI Reports is a leading provider of display energy certificate (DEC) services, partnering with organisations across the public sector, including schools, universities, NHS Trusts, local authorities, and emergency services.
Our consultative approach offers the strategic insights needed to manage energy performance effectively. Our processes are designed to minimise operational disruption while ensuring full adherence to current legislation.
Talk to us for help with:
- Accredited DEC Assessments: Comprehensive audits, reporting, and official certification.
- Compliance Management: A proactive renewal service to mitigate the risk of penalties and lapses.
- Sustainability Advisory: Clear, actionable guidance on enhancing energy efficiency and reducing carbon footprints.
- Legislative Support: Expert navigation of environmental regulations and statutory requirements.
Whether you are responsible for a single building or an extensive national portfolio, ACI Reports provides a reliable, end-to-end solution for your energy compliance needs.
FAQs About DEC Certificates
What’s the difference between a DEC and an EPC?
A DEC measures the actual energy consumed by a building over a 12-month period. An EPC assesses the potential energy efficiency based on the building’s construction and fixed services. They are separate requirements and serve different regulatory purposes.
Can an EPC replace a DEC?
No. An EPC and a DEC are distinct legal requirements. If your building is mandated to have a DEC, a valid EPC cannot be used as a substitute.
Who is responsible for organising a DEC?
The building occupier is legally responsible for commissioning the DEC assessment and ensuring the certificate is clearly displayed to the public.
What is the DEC certificate register?
Every DEC certificate must be lodged on the official national register to be valid. Once registered, the certificate must be displayed in a prominent location within the building, such as a main reception.
What is a recommendation report?
The Recommendation Report is a mandatory document that accompanies the DEC certificate. It provides tailored, practical advice on how to reduce energy consumption and improve the building's overall efficiency rating.
What happens if a DEC is not in place?
Failure to display a valid DEC certificate may result in a £500 penalty, while failing to hold a valid certificate where required may result in a £1,000 penalty.