Indicator Assessment

Heating degree days

Indicator Assessment

Prod-ID: IND-348-en

Also known as: CLIM 047

Published 20 Nov 2012 Last modified 11 May 2021

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Topics: Energy Climate change adaptation

This page was archived on 20 Dec 2016 with reason: Other (New version data-and-maps/indicators/heating-degree-days/assessment was published)

The number of heating degree days (HDD) has decreased by an average of 16 per year since 1980. This helps reduce the demand for heating, particularly in northern and north-western Europe.
Climate change will affect future energy and electricity demand. Climate change is not expected to change total energy demand in Europe substantially across Europe, but there may be significant seasonal effects, with large regional differences.

Trend in heating degree days in the EU-27

Note: Trend in heating degree days in the EU-27 (1980 - 2009). Eurostat calculates heating degree days as (18 °C - Tmean) if Tmean is lower than 15 °C (heating threshold) and zero if Tmean is greater than or equal 15 °C; Tmean is the mean daily outdoor temperature, calculated as Tmean = (Tmin + Tmax / 2)

Data source:

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Trend in heating degree days in the EU-27

Note: The map shows the trend in heating degree days in the EU-27 (1980-2009)

Data source:

Data provenance info is missing.

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Past trends

The number of heating degree days (HDD) has decreased by 13 % over the last 3 decades, yet with substantial interannual variation (Figure 1). Figure 2 shows that the decrease in HDD has not been homogeneous across Europe. The absolute decrease has been largest in the cool regions in northern Europe where heating demand is highest.

Projections

Temperatures in Europe are projected to continue to increase. Hence, the trend of decreasing numbers of HDD is very likely to continue, and most likely to accelerate. For example, the heat demand for space heating in 2050 was projected to decrease by 25 % in the UK [i], and by 9 % in the EU ([ii]).

[i] Martina Flörke et al., Climate Adaptation – modelling water scenarios and sectoral impacts. Final Report Contract N° DG ENV.D.2/SER/2009/0034 (Kassel, Germany: Center for Environmental Systems Research, University of Kassel, Oktober 28, 2011), http://circa.europa.eu/Public/irc/env/wfd/library?l=/framework_directive/climate_adaptation/climwatadapt_report.

[ii] Pre-publication of results from the ClimateCost project (http://www.climatecost.cc)

Supporting information

Indicator definition

Trend in heating degree days in the EU-27

Units

Heating Degree Days (HDD)/year

Rationale

Justification for indicator selection

A ‘Heating Degree Day’ (HDD) is a proxy for the energy demand needed to heat a home or a business; it is derived from measurements of outside air temperature. The heating requirements for a given structure at a specific location are considered to be to some degree proportional to the number of HDD at that location. However, they also depend on a large number of other factors, notably in relation to income levels, building design, energy systems and behavioural aspects. HDD are defined relative to a base temperature, the outside temperature below which a building is assumed to need heating.

Space heating is responsible for a large component of European energy use, so a decrease in the use of space heating has the potential to lead to a significant decrease in overall energy use. There are many contributory factors to heating demand, such as the energy performance of the building envelope, the type of heating system available, occupant behaviour and energy prices. However, the external temperature is the only component which is directly affected by climate change. The number of HDD is therefore a proxy for the energy demand for space heating, and hence an indicator for possible changes in overall energy use directly related to climate change.

An increase in cooling demand would off-set in part or completely the gains from a reduced energy demand for space heating and the effects resulting from a reduction in heating demand. While heating is delivered to end users in different ways (individual boilers fuelled by oil, gas, and coal, and electricity and district heating), cooling is delivered currently almost exclusively through electricity. As a result, a given increase in cooling demand is generally associated with higher costs, a higher increase in primary energy demand and larger impacts on the peak capacity of supply networks than the same decrease in heating demand.

Scientific references

IPCC 2007: Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007. M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J. van der Linden and C.E. Hanson (eds), Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Policy context and targets

Context description

In April 2013 the European Commission presented the EU Adaptation Strategy Package (http://ec.europa.eu/clima/policies/adaptation/what/documentation_en.htm). This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.

The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, http://climate-adapt.eea.europa.eu/) to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.

Targets

No targets have been specified.

Methodology

Methodology for indicator calculation

Eurostat calculates HDD as (18 °C - Tm) x d if Tm is lower than or equal to 15 °C (heating threshold) and zero if Tm is greater than 15 °C, where Tm is the mean (Tmin + Tmax / 2) outdoor temperature over a given period of d days.

A trend line has been added.

Methodology for gap filling

Not applicable

Methodology references

Energy statistics - heating degree-days Reference Metadata in Euro SDMX Metadata Structure (ESMS) Compiling agency: Eurostat, the statistical office of the European Union

Uncertainties

Methodology uncertainty

Not applicable

Data sets uncertainty

Data for calculation of HDD have been collected by Eurostat for decades; this indicator can therefore be considered as very reliable. The same data used could also be used for the calculation of cooling degree days. Such an indicator is currently not available even though it would be highly policy-relevant and could be calculated with little additional effort. It should be noted that the indicator HDD is a purely physical metric, which does not consider differences in technical, social and economic factors (housing quality, behaviour, prices, etc.) between regions and their development over time.

Further information on uncertainties is provided in Section 1.7 of the EEA report on Climate change, impacts, and vulnerability in Europe 2012 (http://www.eea.europa.eu/publications/climate-impacts-and-vulnerability-2012/)

Rationale uncertainty

No uncertainty has been specified

Data sources

Energy statistics (Eurostat)
provided by Statistical Office of the European Union (Eurostat)

Other info

DPSIR: Impact
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)

Indicator codes

CLIM 047

Frequency of updates

Updates are scheduled every 4 years

EEA Contact Info

Permalinks

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Geographic coverage

Austria Belgium Bulgaria Cyprus Czechia Denmark Estonia Finland France Germany Greece Hungary Ireland Italy Latvia Lithuania Luxembourg Malta Netherlands Poland Portugal Romania Slovakia Slovenia Spain Sweden United Kingdom

Temporal coverage

1980-2009

For references, please go to https://www.eea.europa.eu/data-and-maps/indicators/heating-degree-days-1/assessment or scan the QR code.

PDF generated on 24 Apr 2024, 10:41 PM

Dates

First draft created:

15 Nov 2012, 09:27 AM

Publish date:

20 Nov 2012, 06:50 PM

Last modified:

11 May 2021, 11:47 AM

Topics

Topics: Energy Climate change adaptation