How is an EPC produced?
A
Commercial Energy Performance surveyor will conduct
a survey of your building. Construction methods
used in walls, floors, ceilings, windows and roof
are recorded on to data collection sheets. A floor
plan will be drawn of the building if one is not
provided, this will record all physical dimensions
of each area. The building is then divided into
‘zones’ which are the physical boundaries of each
area, the zones are then subdivided if necessary
taking into account distances from windows and
roof lights. Each zone has to represent an area
of activity i.e. office, canteen, corridor etc.
Once
the building is zoned the heating, ventilation
and air conditioning (HVAC) that serves each zone
is recorded as well as the lighting type. The
energy assessor will usually have to speak with
the manufacturers of plant to ascertain information
such as seasonal efficiency of boilers, fan power,
power outputs etc – this can lead to some time
consuming detective work.
This
data is then uploaded to piece of software called
SBEM (simplified building energy model) A database
is created first to record construction and HVAC.
‘Envelopes’ (floors, walls, ceiling/roof, doors,
windows) are then created for each zone and all
related energy usage is linked.
Once
the software has all the information it requires,
it can calculate the CO2 emissions of the building
and generates a graphical document showing the
result listed as A – G. The closer to A, the more
energy efficient the building is. The software
also generates a separate recommendation report
with the EPC and your assessor will generally
email these documents as a .PDF file.
Once
you’ve received the EPC report, it should be reviewed
and any comments made to the assessor within 3
working days. When this is done, your assessor
will upload and lodge the EPC to the National
Register where it will remain valid for a period
10 years or until a new EPC is commissioned.