This Annex evaluated how installation and/or maintenance deficiencies cause heat pumps to perform inefficiently and waste energy. Specifically investigated were the extent that operational deviations are significant, whether the deviations (when combined) have an additive effect on heat pump performance, and whether some deviations (among various country-specific equipment types and locations) have greater impact than others.


The objectives of Annex 36 were:

  • To develop information for use by industry stakeholders, policy makers and owners/operators
  • To evaluate heat pump equipment types and applications that are germane to each participant’s general equipment applications for residential and commercial buildings
  • To enable more efficient heat pump operation by reduced energy utilisation, reduces greenhouse gas emissions and/or to provide for enhances penetration of heat pumps


The Annex were structured into five tasks:

Task 1 Critical literature survey

Task 2 Identify sensitivity parameters

Task 3 Modelling and/or lab-controlled measurements

Task 4 Simulations of seasonal impacts

Task 5 Report and information dissemination

Publication and result

The deliverables of the Annex were:

  • An Internet website
  • A final report (2-page flyer and Executive Summary)

Reports are available at Annex 36 Publications