Display Energy Certificates: Who Needs One

Display Energy Certificates: Who Needs One

A Display Energy Certificate (DEC) is needed when a public authority occupies a building over 250 m² that the public visit often. The occupier must keep a valid DEC on display and hold a valid advisory report.

The three tests

The rule is regulation 14 of the Energy Performance of Buildings (England and Wales) Regulations 2012. A building needs a DEC when all three of these are true:

• It is occupied, in whole or in part, by a public authority.
• Its total useful floor area is over 250 m².
• It is frequently visited by the public.

It also has to be a "building" in the legal sense: a roofed construction with walls that uses energy to condition the indoor climate. In practice that means it has heating, mechanical ventilation or air conditioning. A part of a building that is designed or altered to be used separately counts as a building in its own right.

It is the occupier that counts

The duty sits with the occupier, not the owner. A council that owns a building and lets it to a private company running a business that is not a public service does not need a DEC for it, because the occupier is private. Private organisations never have to display one, even when they share a building with a public body, though they can choose to.

Measuring the 250 m²

Total useful floor area is the gross internal area: all enclosed spaces measured to the inside face of the external walls. Stairs, galleries and raked seating are taken at their area on plan. Open floors, covered ways and balconies are left out. The 250 m² threshold has applied since 9 July 2015.

What the occupier must do

• Display a valid DEC at all times, in a prominent place clearly visible to visitors. Government guidance says it should be no smaller than A3.
• Hold a valid advisory report, unless there is no reasonable potential to improve the building's energy performance.

The DEC rates the building from A to G on its actual metered energy use over 12 months, compared with a typical building of the same type. A typical building scores 100. The advisory report lists improvements by payback: up to 3 years, 3 to 7 years, and over 7 years.

How long a DEC lasts

• Over 1,000 m²: the DEC is valid for 12 months and the advisory report for 7 years.
• 250 to 1,000 m²: both are valid for 10 years.

Validity runs from the nominated date. The assessor sets it no later than three months after the end of the 12 months the meter readings cover. So for a larger building, a new DEC is due every year.

A new occupier who has been in the building for less than 15 months won't have a full year of readings yet. The regulations allow for that, and the rating is worked out over the time they have been in occupation.

DEC or EPC?

An EPC rates how a building is built. A DEC rates how it is run. A public building only needs an EPC when it is built, sold or let, or modified in certain ways. If it has an EPC, that rating has to be shown on the DEC.

If the building has air conditioning over 12 kW, it also needs a TM44 inspection at least every five years. We carry those out ourselves, and can do the commercial EPC on the same visit.

Penalties

Trading Standards enforce the rules. The penalty is £500 for not displaying a valid DEC and £1,000 for not holding a valid advisory report. Paying it doesn't end the matter: the documents still have to be commissioned. A penalty notice can be reviewed, and then appealed to the county court within 28 days of the review decision.

Are the rules changing?

The government consulted on reforms to energy performance certificates from December 2024 to February 2025, including when DECs are needed and how long they last. Its partial response in January 2026 (updated March 2026) left DECs for a further response. That had not been published when we wrote this in November 2026, so the rules above still apply.

How we help

We don't produce DECs ourselves. We introduce a trusted accredited DEC assessor, who quotes, produces the DEC and advisory report, lodges them on the government register and invoices you directly. We may receive an introduction fee from the partner. Only an accredited energy assessor can produce a DEC, and for the first one they must visit the building.

For a quote, send us:

• 12 months of meter readings or bills for every fuel
• floor plans or the floor area
• opening hours
• the previous DEC, if there is one

Turnaround is 5 working days once the partner has everything. If we've already done a TM44 or commercial EPC on the building, we can pass the floor areas and plans on with your OK.

Questions we get asked

Do private offices need a DEC? No. Only buildings occupied by a public authority and frequently visited by the public. A private company can display one voluntarily.

How often does a DEC need renewing? Every year for buildings over 1,000 m², and every 10 years for buildings of 250 to 1,000 m². The advisory report lasts 7 years over 1,000 m² and 10 years below that.

How can I check a DEC is genuine? Every DEC is lodged on the government register with a unique reference number. You can search the register by that number or by the address.

Do we have to act on the advisory report? No. The recommendations are for information. Acting on them usually cuts energy bills and improves the next rating.

More: Display Energy Certificates, TM44 inspections, who needs a TM44 inspection, commercial EPCs, how long a commercial EPC lasts, industry updates.

Email your energy data or WhatsApp us for a free quote.