DEC Certificates are required for schools, colleges, universities, leisure centres, hospitals, nursing homes, public libraries, museums and art galleries.
From the 1st of October 2008, it is mandatory for all public buildings of 1000 m2 or bigger to display a DEC certificate in a prominent place so that it is clearly visible to the public.
What does an advisory report contain?
The advisory report includes a series of recommendations for possible improvements ranging from zero and low cost operational management improvements to the more expensive measures such as changing building fabric or services and the addition of low and zero carbon (LZC) technologies.
The report is intended to help the occupier identify factors that could improve the building’s energy management and thus reducing energy use and CO2 emissions.
The recommendations are categorised according to their respective payment periods as follows:
�Short-term payback (up to three years), such as building energy management measures
�Medium-term payback (three to seven years), such as upgrading building services
�Long-term payback (more than seven years), such as Low and Zero Carbon (LZC) technologies
Penalties for not having a DEC Certificate
A penalty charge of 1500 by the local authorities may be applicable to buildings that fail to produce a DEC certificate at all times. Failure to commission the required documents in addition to the fine may account for further offences and hence more fines.
What factors affect the Display Energy Certificate Rating?
DEC ratings of buildings are hugely influenced by the gas and/or energy consumption and are totally different to EPC and SBEM calculations where the software makes a number of assumptions based on the input data and calculates the energy consumption resulted in heating, hot water and lighting and ventilation based on a standardised model. This leads to a discrepancy between the rating calculated and the actual energy consumption as the calculations are independent of energy consumption by cooking, electrical appliances and other utilities.
Display Energy Certificate (DEC) ratings are generated by calculations based on the actual meter readings and no assumptions are made and nothing is compared to standardised models.
Despite this, the DEC rating is still not a perfect model as one of its main defects is that the effect of renewable energy cannot be shown in the software if the units are not sub-metered. It means that if a CHP exists in a building, its presence will not benefit the building as it cannot be input into the software unless it is linked to a separate meter and the gas and electricity readings can be seen.
Another major problem with the DEC is that when the DEC calculation is generated, the software automatically compares it to the benchmark to give a rating. However, some facilities might be present in the sites which are not included in the benchmark and unless these facilities are sub-metered they cannot be excluded from the calculation causing it to show an energy rating which is much worse than the building’s actual rating.
Meter readings are the only form of data that can be fed to the DEC software. However, when it comes to the advisory report it all seems a bit complicated as the assessor needs to include all the systems that are present in the site and identify the system conditions briefly. The recommendation report, however, has no effect on the DEC rating as meter readings would be independent of the condition of the building’s utilities. For instance, even if the conditions of utilities are very good in a building, it can still get a poor rating if the meter readings are high and vice versa.
Display Energy Certificates are renewed energy year and therefore it is possible to monitor and compare the energy consumption of consequent years and observe improvements. Also, the recommendations included in the DEC are very useful as some of them are either cost free or inexpensive to adopt and so improvements are possible even in a span of few years.
