Metadata and Methodologies

EHPA sales data acquisition and processing methodology

The EHPA Market Report presents data on heat pumps providing heating, heating & cooling and/or sanitary hot water, as well as on those contributing process heat. Units sold are collected via a standardised questionnaire from national heat pump associations, statistics bureaus and research facilities alike.

Deviations between totals presented in chapter 1 and chapter 3 and national markets presented in chapter 4 result from:

• The availability of detailed longitudinal data. Aggregated numbers were not used for data accumulation but were only listed in the national chapters.

• A lack of transparency for numbers provided in the category “other”. Units sold were integrated into total sales, but not used in the calculation for RES use, energy efficiency and GHG savings.

• The numbers on industrial heat pumps. They are shown in Table 3.3-1, but not in national chapters. Their contribution to RES use, energy efficiency and GHG savings is not yet counted.

Accounting for sales of reversible heat pumps

The report maintains a focus on heat pumps providing a heating function and/or sanitary hot water in line with the requirements of the RES Directive (see ch. 3).

To ensure this focus, the following corrections have been applied:

• Air/air units: The use of air/air heat pumps predominantly for heating is assumed for countries in cold climates (Estonia, Denmark, Finland, Lithuania, Norway). The number of units reported results from total sales adjusted by a correction factor (around 10%) aiming to exclude AC-only units. It is applied by the national heat pump associations. In the case of Sweden, where air/air sales data is not collected by the national association any longer, the number of air/air units has been estimated by EHPA based on the sales for 2011.
  Air/air units sold in the average climate zone have not been counted, due to a lack of reliable information on their use for heating or cooling.
  For countries in the warm climate zone (France, Italy, Portugal and Spain) only a share of the total sales number has been included in the report. A study of the Italian market comes to the conclusion that in 9.5 % of all dwellings, reversible air/air heat pumps were the only heat generator installed. This value is used for Italy with a similar assumption being taken for Portugal, Spain and southern France.
  For information purposes, the total sales number of air/air units is shown in Table 3.3-1 (shaded).

• Air/water & brine/water units: Reversible heat pumps connected to hydronic systems are always counted, as their primary use as heating system can be assumed.

• Hybrid heat pumps:
  There is no clear definition of what a hybrid heat pump is, due to the manyfold ways to integrate heat pumps with other technologies. In order to integrate this new class of systems into our database, the national heat pump associations and EHPA agreed on the following broad definition: A hybrid heat pump is the combination of a heat pump and a fossil fuel based boiler that has a controller between both heaters and is designed to be sold together under one commercial reference.

• VRF units: VRF systems are counted, as they are specifically designed for heating and cooling. 90% of the reported sales numbers are included in the EHPA statistics in order to allow for deviations from declared use (i.e. used for cooling only).

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Calculating the environmental benefits of the heat pump stock

RES

Heat pumps use renewable energy sources (RES). As they require an amount of auxiliary energy to operate the compressor, the useful energy provided (Q_usable) is only 100% renewable, if also this auxiliary energy comes from renewable sources. In those cases, where auxiliary energy from fossil sources is used, a calculation method is needed to identify the renewable fraction of energy production.

As a result of the introduction of the RES Directive, the Commission has presented its own approach on how to calculate the RES share of heat pumps. This method is supposed to be used by the statistics offices of all Member States. It provides rather conservative factors for the calculation of the useful energy provided by heat pumps as well as for their seasonal efficiency. The Commission suggests that Member States develop more realistic values based on a robust national approach, whereby local conditions are taken into consideration.

Following formula is used to calculate the share of renewable energy (E_RES):

E_RES = Q_usable * (1 - 1/SPF)

Q_usable = HHP * P_rated

, where:

• Q_usable = the estimated total usable heat delivered by heat pumps,

• HHP = equivalent full load hours of operation,

• P_rated = capacity of heat pumps installed,

• SPF = the estimated average seasonal performance factor.

The total capacity of installed heat pumps (P_rated) is based on the number of units sold multiplied by a factor representing the capacity per unit. This parameter is not specified in the decision and thus, EHPA industry data and expert estimates are applied. The values are shown in Table 5.2-1 (in Annex 5.2).

The Commission provides default values for HHP and SPF. Particularities of different heat pump types and climate zones are taken into account, so that there is one value for each combination (Table 5.2-2 and Table 5.2-3).

These formulas are then applied to all heat pump categories and the respective results are aggregated to finally yield the total renewable contribution from heat pumps (E_RES) per Member State of the European Union (MS).

Not all heat pumps are considered in the calculations. Following systems are either completely excluded or corrected:

Systems with an SPF below 2.53* are excluded
Exhaust air heat pumps are only partly considered (30%)
Reversible air-to-air heat pumps in average and warm climates are only partly considered.

Exhaust air heat pumps

Exhaust-air heat pumps use aerothermal energy. Part of the energy used comes form a re-use (via heat exchangers) of indoor air, part of it comes from outdoor air that is drawn into the building. Initial analysis shows that 30% to 50% of the energy used comes from outdoor air. In order to provide (yet again) a cautious estimate, the contribution from exhaust air heat pumps is generally weighted with a factor of 0.3.

Reversible air/air heat pumps installed in warm climates

As described earlier, a large number of reversible air-air heat pumps are installed in Europe. In Scandinavian and Baltic climates, their use for heating is simply assumed on the basis of the prevailing cold climate. For southern Europe, a different approach has been taken. It is based on a study done for the Italian market to determine the type of heating systems used. This study has been used as guidance for the calculation of the share of heating provided by heat pumps in the EHPA methodology. It has now been translated in modified heating hours for the Mediterranean countries in the commission study.

Energy savings

The energy consumption of the heating systems can be reported in terms of final or primary energy. While the former describes simply the amount of auxiliary energy needed to drive the system, the latter also accounts for the efforts undertaken to provide this energy. For instance, when electricity is used to power the heat pump, the final energy consumed by the heat pump is multiplied with the Primary Energy Factor (PEF). The greener the electricity mix the smaller the PEF – the closer are the primary to the final energy savings.

Actual savings are calculated by comparing the final/primary energy consumption of a heat pump to that of a (replaced) gas-condensing boiler. For the heat pump, the aforementioned efficiency assumptions (SPF) are taken by category, for the gas boiler the efficiency is set at 85 % (upper heating value).

Emission savings

Similarly to the energy savings, the CO2-emission savings are calculated by comparing the emissions from a heat pump to those of a (replaced) gas- condensing boiler. Parameters used are: eta for gas: 85 %, emission value for gas: 242g/kWhth and emission value for electricity: 334g/kWh, a value that represents the EU-27 average for 2021. For heat pump seasonal efficiency, the values from Table 5.2-4 were used.

The results must be considered (again) as a cautious estimate, as in reality, not only gas but also oil boilers as well as coal boilers and direct electric heating systems are replaced. All of them have higher emissions than a gas boiler per kWh of thermal energy and thus the heat pump benefits calculated are lower than to be expected in reality. In addition, the replacement speed of oil boilers is most likely higher than that of gas boilers, as the cost advantage of heat pumps is higher, when oil boilers are replaced.