# Commission Delegated Regulation (EU) 2015/1187 of 27 April 2015 supplementing Directive 2010/30/EU of the European Parliament and of the Council with regard to energy labelling of solid fuel boilers and packages of a solid fuel boiler, supplementary heaters, temperature controls and solar devices (Text with EEA relevance), Division 1: The Energy Efficiency Index (EEI) of solid fuel boilers shall be calculated for the preferred fuel and rounded to the nearest integer as:

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

EEI = ηson × 100 × BLF – F(1) – F(2) × 100 + F(3) × 100
where:
(a) ηson is the seasonal space heating energy efficiency in active mode, calculated as set out in point 4(b) of Annex VIII;
(b) BLF is the biomass label factor, which is 1,45 for biomass boilers and 1 for fossil fuel boilers;
(c) F(1) accounts for a negative contribution to the energy efficiency index due to adjusted contributions of temperature controls; F(1) = 3;
(d) F(2) accounts for a negative contribution to the energy efficiency index by auxiliary electricity consumption, and is calculated as set out in point 4(c) of Annex VIII;
(e) F(3) accounts for a positive contribution to the energy efficiency index by the electrical efficiency of solid fuel cogeneration boilers, and is calculated as follows:
F(3) = 2,5 × ηel,n

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Source: https://www.legislation.gov.uk/eur/2015/1187/annex/IX/division/1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2015-1187/annex-IX/division-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.