Division (a): Conventional water heaters and heat pump water heaters - 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)

The water heating energy efficiency is calculated as follows:

η_{wh} = \frac{Q_{ref}}{(Q_{fuel} + CC \times Q_{elec}) (1 - SCF \times 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.

Division (a) Conventional water heaters and heat pump water heaters