Last edited 17 Aug 2019

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BRE Group Researcher Website

Home energy performance ratio

The Home Quality Mark One, Technical Manual SD239, England, Scotland & Wales, published by BRE in 2018 defines the Home energy performance ratio (HEPR) as:

A metric that is unique to the HQM that is calculated by the HQM energy engine using modelled outputs from approved building energy calculation software, against which HEPR credits are awarded.

It is a ratio that defines the performance of a HQM assessed home in terms of its:

  1. Heating and cooling energy demand (the fabric performance).
  2. Primary energy consumption (system efficiency).
  3. Total resulting CO emissions.

For each metric, the homes actual performance is compared against the relevant National Building Regulations compliant standard (i.e. a baseline), and the comparison expressed as a percentage improvement.

The percentage improvement for each metric is then compared against a best practice performance level for modelled stock of house types, and then ‘translated’ into a ratio of performance for each metric. These ratios are then weighted for each metric and added together to determine a single overall HEPR.

A description of how to obtain a home’s HEPR is summarised in Methodology on P123 of the Manual. Greater detail of how the HEPR is defined and calculated is provided in the HQM energy guidance document.

--BRE Group

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