# Commission Regulation (EU) No 1253/2014 of 7 July 2014 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for ventilation units (Text with EEA relevance), Annex VIII: Calculation of the specific energy consumption requirement

Extent: E+W+S+N.I.

The specific energy consumption SEC is calculated with the following equation:
SEC = t a × pef × q net × MISC × CTRL x × SPI − t h × ΔΤ h × η – 1 h × c air × q ref − q net × CTRL × MISC × 1 − η t + Q defr
where:
SEC is Specific Energy Consumption for ventilation per m2 heated floor area of a dwelling or building [kWh/(m2.a)];
ta is annual operating hours [h/a];
pef is primary energy factor for electric power generation and distribution [-];
qnet is net ventilation rate demand per m2 heated floor area [m3/h.m2];
MISC is an aggregated general typology factor, incorporating factors for ventilation effectiveness, duct leakage and extra infiltration [-];
CTRL is ventilation control factor [-];
x is an exponent that takes into account non-linearity between thermal energy and electricity saving, depending on motor and drive characteristics [-];
SPI is Specific Power Input [kW/(m3/h)];
th is total hours heating season [h];
ΔΤh is the average difference in indoor (19 °C) and outdoor temperature over a heating season, minus 3K correction for solar and internal gains [K];
ηh is the average space heating efficiency [-];
cair is the specific heat capacity of air at constant pressure and density [kWh/(m3 K)];
qref is the reference natural ventilation rate per m2 heated floor area [m3/h.m2];
ηt is the thermal efficiency of heat recovery [-];
Qdefr is the annual heating energy per m2 heated floor area [kWh/m2.a] for defrosting, based on a variable electric resistance heating.
Q defr = t defr × ΔΤ defr × c air × q net × pef ,
where
tdefr is the duration of defrosting period, i.e. when the outdoor temperature is below – 4 °C [h/a], and
ΔΤdefr is the average difference in K between the outdoor temperature and – 4 °C during the defrosting period.
Qdefr applies only to bidirectional units with recuperative heat exchanger; for unidirectional units or units with regenerative heat exchanger is Qdefr = 0.
SPI and ηt are values derived from tests and calculation methods.
Other parameters and their defaults are given in Table 1.
Table 1
SEC calculation parameters
Defrosting applies only to bidirectional units with recuperative heat exchanger and is calculated as Qdefr = tdefr * Δtdefr * cair * qnet * pef. For unidirectional units or unit with regenerative heat exchanger is Qdefr = 0
general typology
MISC
Ducted units
1,1
Non-ducted units
1,21
ventilation control
CTRL
Manual control (no DCV)
1
Clock control (no DCV)
0,95
Central demand control
0,85
Local demand control
0,65
motor & drive
x-value
on/off & single speed
1
2-speed
1,2
multi-speed
1,5
variable speed
2
Climate
th in h
ΔΤh in K
tdefr in h
ΔΤdefr in K
Qdefr in kWh/a.m2
Cold
6 552
14,5
1 003
5,2
5,82
Average
5 112
9,5
168
2,4
0,45
Warm
4 392
5
—
—
—
Defaults
value
specific heat capacity of air, cair in kWh/(m3K)
0,000344
net ventilation requirement per m2 heated floor area, qnet in m3/h.m2
1,3
reference natural ventilation rate per m2 heated floor area, qref in m3/h.m2
2,2
annual operating hours, ta in h
8760
primary energy factor electric power generation & distribution, pef
2,5
space heating efficiency, ηh
75 %

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Source: https://www.legislation.gov.uk/eur/2014/1253/annex/VIII (the official version)
Page: https://openlegislation.uk/eu-regulation-2014-1253/annex-VIII
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.