From 1 October this year Display Energy Certificates (DECs) must be prominently displayed in all public buildings over 1,000 m2 which are frequently visited by the public
by Dave Cocking
11 September 2008
The DEC will convey the Operational Rating (OR) of the building on a scale of 0-200 and labelled from A to G. The OR is a measure of the annual CO2 emissions per unit area compared to a benchmark building of the same type and size.
A DEC is valid for one year and must be accompanied by an in-date Advisory Report (AR), which is valid for seven years. The AR shows the top 30 recommendations based on likely payback period and carbon impact. There is no requirement to display the AR, but the FM must ensure that it is controlled and available on site.
Non-domestic energy assessors must be accredited specifically to produce DECs, and the FM is advised always to check this on the website of either the energy assessor's accrediting body or the government website at www.ndepcregister.com. The DEC assessment is based on 365 days of energy consumption with a maximum gap of three months between the end of the assessment period and the start date of the DEC.
The consumption data must come from the supplier (actual or estimated) or site meter readings. Unmetered solid and liquid fuels such as biomass and oil will require delivery notes and confirmation of stock levels at the start and end of the assessment period. If adequate energy consumption data cannot be provided the building automatically gets a worst-case OR of 200. Unmetered buildings on grouped sites such as campuses can be certified using an area-weighted method based on the site meter readings.
The energy consumed by some legally 'separable' processes not typical for the type of building - such as a regional server room in an office - can be subtracted subject to strict rules. Credit is given on the certificate for on-site renewables and low and zero carbon energy sources providing they are sub-metered. The other significant factors in determining the OR are floor area and occupancy hours, and where the FM can prove occupancy is higher than the benchmark the energy assessor can use this to produce a more representative OR.
The DEC and AR can be produced by either a walk-round survey or a desktop study if the necessary information is provided by a third party with sufficient knowledge of the building. The organisation is responsible for the information it provides. The desktop study method was originally intended for use by organisations using in-house assessors familiar with each building, but seems to have been adopted by some companies as a standard procedure. Government guidance clearly recommends a site survey where the energy assessor has no prior knowledge of the building.
The key question to ask before commissioning your DEC is whether your priority is basic compliance or whether you wish to use the process to add some value. Using an accredited expert such as a low carbon energy assessor with a fresh pair of eyes is the best way of identifying potential energy savings, which in turn can improve future ORs.
Given the recent explosion in energy prices the cost of the site visit should have a very short payback if the advice provided in the more accurate AR is implemented. ARs produced by external organisations using desktop surveys are likely to be highly generic unless the client has the time and expertise to gather the necessary data.
Limited information is available on the government website at www.communities.gov.uk and from there you can download the publication A guide to Display Energy Certificates and Advisory Reports for public buildings. The accrediting body websites such as www.cibsecertification.co.uk contain a raft of good up-to-date information and can help you to find an accredited assessor. Entering the term "display energy certificate" into a search engine will highlight some useful sources
of further information, but as always care needs to be taken when using unknown internet sources.
Dave Cocking is the managing director of Arrow Energy Solutions
Top tips on display energy certificates
- Review the government's guide to DECs, noting the details regarding alignment of energy data and legally separable processes
- Confirm that you actually require a DEC using the guide; if in doubt you are advised to display one until you can confirm exemption
- Gather validated energy consumption data for all sources
- Gather plans/proof of area to reduce the time and cost of the assessment. Use GIA, not NLA or SFA, to prevent being penalised by 'conservative' conversion factors
- Gather occupancy evidence for the different activity areas of your building
- Ask your energy assessor for a questionnaire in advance of the assessment to give you time to gather the information required to produce the AR (maintenance policies etc)
- Consider where and how you will display your A3-size DEC, and if necessary specify a laminated or framed certificate - remember these must be prominently displayed in your main foyer or similar area
- Identify a non-domestic energy assessor accredited for DECs and discuss your requirements, particularly regarding the issue of site visit or third party information