FAQ - Display Energy Certificate (DEC) for Large Public Buildings
What is a Display Energy Certificate(DEC)?
From the 1st January 2009, public bodies occupying buildings over 1,000m2 are required to exhibit a DEC, in a prominent place, clearly visible to the public. The DEC is intended to encourage public authorities to adopt environmentally responsible and efficient use of energy in buildings.
What is the definition of a public body?
The definition of a public body is contained in S.I. No. 666 of 2006. It includes any public body or public authority/ institution set up by Government enactment. The Dept of State, Local Authorities, HSE and public educational establishments.
What is the format of the DEC?
The DEC is based on the measured energy use, where the actual energy consumed in the building is compared to a benchmark for similar buildings, and shown on the certificate A1 - G scale in terms of primary energy. There is also a CO2 indicator which shows the CO2 emissions associated with the building's energy consumption. Benchmark or typical buildings have a E1 rating. The DEC layout is specified in S.I. 666 of 2006.
Back to top
How is a DEC calculated?
The DEC rating is calculated on the basis of the ACTUAL energy consumption, during occupation, over a ONE YEAR period. The DEC reflects the use of the building and the practices of management and maintenance. This is calculated from meter readings/ bills or an alternative reliable source. From this, an operational rating is derived. The energy used by the building over the year is required. This may include gas fuels, oil fuels, solid fuels, district heating and cooling and electricity. Energy consumption is ideally obtained directly from onsite incoming energy meters, or from energy supply company bills. If this information is not available from those maintaining the building or the landlord, an estimate should be provided from the energy supplier. The Assessor can only use estimates data directly from the energy supplier and no other source.
Back to top
How do you calculate a DEC for campus facilities?
Many public services have campus style facilities where metering is at the site level rather than at the building level. In such cases, the DEC should be based on the metered site energy demands, and the energy used by each building would be determined from the site energy consumption on a simple area weighted basis. A DEC should be displayed for each qualifying building. All public building over 1000m² should be included.
Benchmark
Ireland has adapted the methodology, developed in the UK, for the purposes of generating the DEC. The benchmarks are adjusted to take local factors into consideration. Additional software has been developed to aid the calculation procedure. The set of benchmarks relate to specific building use categories with standard use patterns and are made for specific locations and climate. Provisions are made for the following:
- Where the actual building usuage covers more than one of the chosen building use categories . This composite benchmark is derived on a pro rata basis, taking account of the floor area applicable to each identified use.
- Where there is significant climate differences between the location of the building being assessed and that assumed in the standard benchmark.
- Where the use periods of the builidng are significantly greater than those assumed in the standard benchmark, up to a set limit of extended use.
- Energy used for specific identified processes, may be excluded in exceptional circumstances. As part of the benchmarking process, CIBSE has identified activities that can be considered as significantly more intensive in their use of energy relative to those usually found in a particular building use category. Where these occur, both the energy use and floor area associated with the particular activities can be ommited from the assessment, provided that the separable energy uses are separately metered.
Back to top
When is the exhibition of a Display Energy Certificate (DEC), legally required?
From January 2009 a DEC is required if a public body occupies an area of more than 1000m², irrespective of whether the body has direct control of the energy services.
Are any buildings exempt from the requirement for a DEC?
If a public body occupies a building less than 1,000m2 then a DEC is not required. However SEAI encouages public bodies to generate and display a DEC for all buildings.
Back to top
Does the DEC relate to a whole building or to the part of a building occupied by a Public Body?
Each public body is treated as a separate building, regardless of the number of organisations sharing a building or floor space, providing that individual organisation is over 1000m². However, if there is a number of organisations in a large building and some are over and some are under 1000m², there should be one DEC for the whole building and named as the building address rather that all the indiviual companies in it. Where all or part of a building is occupied by a public body, the parts occupied by each public body should be treated separately. There are two exemptions: 1) where a variety of companies occupy one space but the space hasnt been altered with partitions etc. 2) Where the management of the energy system is under one common control.
How soon after occupation can a DEC Assessment be carried out?
A DEC can be carried out at any time. If the building has just been occupied and therefore there is not sufficient billing data available, then use the workbook, worksheet Building Inputs, in response to the question - 'Do you have metered, estimated or apportioned measurements of energy consumption to cover more than 95% of all the energy used by the building? (No to this question results in a 'G' grade energy rating.)' use the drop down in cell I25 to answer 'No' and thus default to a G rating.
Back to top
What happens if there is not a sufficient amount of data?
If there isnt sufficient billing data available, the rating will default to G.The data has to be metered or an estimated measurements of energy consumption to cover more than 95% of energy used by the building.
Who can carry out a DEC Assessment?
Anyone seeking to register as a DEC Assessor, must meet the following criteria-
- Hold a degree in a building related discipline (Level 7 under the national framework for qualifications)
- Attend and sucessfully complete a half day DEC Workshop, for large public buildings.
Back to top
How is the DEC generated?
The DEC procedure involves the collection of all relevant data required to produce the certificate, by the registered Assessor. The data is put into a workbook and forwarded on to SEAI for processing. The DEC is generated by SEAI. Once the relevant party receives the DEC, it must be displayed in a prominent place. The certificate displays the grade awarded, an energy perfomance indicator, a CO2 performance indicator, histograms of trends in energy, primary electrical and heating energy per unit, a building identifier, basic building technical information, period of validiity of the DEC, a unique DEC number and DEC Assessor number.
Where should the public body display the DEC?
In addition to the hard copy on display, public bodies may wish to provide a valid cert via a website or other publicly accessible media, show the full technical data that gives underlying details on the building and its energy performance and display supplementary information to explain the contents of the certificate, including any reasons explaining poorer/ better performance to the previous years result.
Back to top
How does a DEC differ from the BER (Building Energy Rating), that is required at construction, sale or rent of a building?
Building Energy Rating (BER) rating for domestic and non domestic buildings is a rating certificate based on calculated energy use.
Display Energy Certificate (DEC) rating is a rating certificate based on measured energy use.
Do private buildings for sale or rent require a DEC?
No. When any building (private or public) is offered for sale or let a BER certificate is required. This certificate is valid for 10 years.
If a private building gets a DEC, does the information appear on the valid DEC list?
SEAI is not accepting voluntary DEC ratings from private organisations at this time. Currently, the only buildings that have DEC's are public buildings.
Back to top
School DEC'S
The Department of Education and Science, in consultation with SEAI, has developed a website for primary and secondary schools to facilitate the generation of Display Energy Certificates. Please visit www.energyeducation.ie for further information.
Technical Bulletin for Large Public Buildings
Public buildings technical bulletin Dec 09.pdf (size 259.7 KB)
Its content includes information on:
- Non Metered energy use
- Stock Levels
- District heating co efficients
- Metered energy use
- Utility bills
- Occupancy hours
- Calculating floor areas
Back to top
