National Calculation Methodology (NCM) - Scottish Government

4 Energy Performance Certificates (EPCs).
66. Energy Performance Certificates (EPCs) provide prospective buyers/tenants with
information about the energy performance of a building and practical advice on
improving performance. Cost effective recommendations for improving the energy
performance of the building detailed on the certificate must meet the Scottish
building regulations, be specific to the individual building and be technically
feasible. The EPC displays the “rating” of a building in the form of the approximate
annual Building CO2 Emission Rate (BER) in kg per m 2 of floor area per year,
rated on a seven band scale (see clause 6.9.2 of Section 6).
67. While an EPC is not required for permanently unconditioned buildings (i.e.
buildings which do not use energy to condition the indoor climate and are expected
to remain this way), it is possible to voluntarily produce EPCs for unconditioned
buildings. Permanently unconditioned buildings are different to those which are
currently unconditioned but are intended to be conditioned prior to occupation, and
which should be modelled as per the guidance on shell and fit out buildings in
Section 6. Further guidance on EPCs is provided in the BSD website 19 .
68. The EPC ‘A to G’ scale and energy labels corresponding to values of the BER are
displayed in, with “Carbon Neutral” being the most efficient (followed by “A+”) and
“G” being the least efficient. This is a seven band graphical scale where a letter
rating or letter plus rating are shown on the same band.
69. The EPC is accompanied by a “Recommendations Report”, which contains a list of
NCM recommendations, edited and added to by the assessor, for the improvement
of the energy performance of the building and their respective potential impact on
the CO2 emission rate of the building. The recommendations are grouped into the
following sub-sections in the report: short payback (up to 15 recommendations),
medium payback (up to 10 recommendations), long payback (up to 5
recommendations), and other recommendations created by the assessor (up to 10
recommendations).
70. The EPC itself displays the top 6 of the short payback (i.e. three years or less)
NCM recommendations. If there are user-defined or user-edited
recommendations, then the EPC displays the top 3 NCM cost effective
recommendations with a payback period of three years or less and up to 3 user
recommendations with the shortest payback.
71. The impact of the recommendations on the CO2 emission rate of the building and
their estimated payback 20 is assessed based on the energy performance of the
actual and notional buildings.
19
http://www.scotland.gov.uk/Topics/Built-Environment/Building/Building-standards/publications/pubepc
20
Details of the logic used for generating the NCM recommendations, their impacts, and paybacks are in
the SBEM Technical Manual available from the NCM website at www.2010ncm.bre.co.uk.
23