The following abbreviations are used in Figure 1:

E_{S_fan/pump}

Energy used to run fan and/or pump that circulates the refrigerant

E_{HW_hp}

Energy used to run the heat pump itself

E_{bt_pump}

Energy used to run pump that circulates the medium that absorbs the ambient energy (not relevant for all heat pumps)

E_{HW_bu}

Energy used to run supplementary heater (not relevant for all heat pumps)

E_{B_fan/pump}

Energy used to run fan and/or pump that circulates the medium that supplies the final usable heat

Q_{H_hp}

Heat supplied from the heat source via the heat pump

Q_{W_hp}

Heat supplied from the mechanical energy used to drive the heat pump

Q_{HW_hp}

Heat supplied from the supplementary heater (not relevant for all heat pumps)

E_RES

Renewable aerothermal, geothermal or hydrothermal energy (the heat source) captured by the heat pump

E_RES

$E_{\mathrm{RES}}=Q_{\mathrm{usable}}-E_{S_{–}\mathrm{fan}∕\mathrm{pump}}-E_{{\mathrm{HW}}_{–}\mathrm{hp}}=Q_{\mathrm{usable}}*\left(1-1∕\mathrm{SPF}\right)$

Q_usable

$Q_{\mathrm{usable}}=Q_{H_{–}\mathrm{hp}}+Q_{W_{–}\mathrm{hp}}$

It follows from the system boundaries set out above, that the calculation of renewable energy supplied by the heat pump depends on the heat pump alone and not the heating system the heat pump is a part of. Inefficient use of heat pump energy is therefore a matter of energy efficiency, and should therefore not influence the calculations of renewable energy supplied by heat pumps.