# Commission Regulation (EU) No 814/2013 of 2 August 2013 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to ecodesign requirements for water heaters and hot water storage tanks (Text with EEA relevance), Division (a): Conventional water heaters and heat pump water heaters

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

The water heating energy efficiency is calculated as follows:
η wh = Q ref Q fuel + CC × Q elec 1 − SCF × smart + Q cor
For water-/brine-to-water heat pump water heaters, the electricity consumption of one or more ground water pumps shall be taken into account.

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Source: https://www.legislation.gov.uk/eur/2013/814/annex/IV/division/3/division/a (the official version)
Page: https://openlegislation.uk/eu-regulation-2013-814/annex-IV/division-3/division-a
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.