Archive:Heating and cooling degree days - statistics
Data extracted in December 2020.
Planned article update: May 2021.
Highlights
Heating degree day (HDD) index is a weather-based technical index designed to describe the need for the heating energy requirements of buildings. Cooling degree day (CDD) index is a weather-based technical index designed to describe the need for the cooling (air-conditioning) requirements of buildings. We derive HDD and CDD data from meteorological observations of air temperature, interpolated to regular grids at 25 km resolution for Europe. We aggregate calculated gridded HDD and CDD and we present them on NUTS-2 level.
Full article
Cooling and heating degree days by country
Higher heating degree days values in Sweden and Finland
Heating degree days vary across European countries. As depicted at figure 1, the annual averages for all available data spanning across 41 years, from 1979 to 2019 show the calculation for Finland is 5,684.86. For Malta, we calculate it at 539.05, which is more than 10 times less. After Finland, Sweden follows with the value of 5,346.04 and Estonia (4,363.51) (Figure 1). The European countries with lower heating degree days, after Malta, are Cyprus 787.53 and Portugal (1,248.90).
Figure 2 presents the situation on heating degree days in the latest year under observation (2019). Again, the countries with the higher values are Finland (5,482.97), Sweden (5,119.61) and Estonia (3,883.05). The countries where we observe the lower values for 2019 are Malta (515.23), Cyprus (693.06) and Portugal (1,109.07).
Higher cooling degree days in Cyprus and Malta
Similar to heating, cooling degree days vary across Europe. Figure 3 shows the annual averages across all available data spanning across 41 years, from 1979 to 2019. Cyprus has the highest values for CDD at 567.88, followed marginally by Malta (566.61) and Greece (266.54). Ireland has the lowest (0.02), and then it is Sweden with 0.36 and Denmark at 0.92.
Figure 4 presents the situation on cooling degree days in the latest year under observation (2019). Again, the countries with the higher values are Malta (756.22), Cyprus (754.00) and Greece (373.09). The countries where we observe the lower values for 2019 are Ireland (0.00), Finland (0.96) and Sweden (0.98).
The highest value ever observed for heating degree days was in January 1985 in Finland (1,197.70) and the highest value ever observed for cooling degree days was in August 2010 in Cyprus (269.13).
Cooling and heating degree days by NUTS 2 regions
Higher heating degree days values in Norrbottens län and Lappi regions
On regional level, the annual averages for all available data spanning across 41 years, from 1979 to 2019 show that Norrbottens län region in Sweden has the higher heating degree days value (6,678.54). We observe the lower value in Fuerteventura, Spain with the values of 18.30. In 2019, we measured in Lappi, Finland the higher heating degree days value at 6,672.02. The lower was in Fuerteventura, Spain with 0.
Higher cooling degree days values in Gozo and Comino / Ghawdex u Kemmuna and Kypros regions
On regional level, the annual averages for all available data spanning across 41 years, from 1979 to 2019 show that Gozo and Comino / Ghawdex u Kemmuna region in Malta has the higher cooling degree days value (581.10), followed by Cyprus at 567.88. In 2019, we measured in Gozo and Comino / Ghawdex u Kemmuna in Malta the higher cooling degree days value at 768.55.
Source data for tables and graphs
Methodology
Heating Degree Days (HDD) index: the severity of the cold in a specific time period taking into consideration outdoor temperature and average room temperature (in other words the need for heating). The calculation of HDD relies on the base temperature, defined as the lowest daily mean air temperature not leading to indoor heating. The value of the base temperature depends in principle on several factors associated with the building and the surrounding environment. By using a general climatological approach, the base temperature is set to a constant value of 15°C in the HDD calculation. If Tm ≤ 15°C Then [HDD = ∑i(18°C - Tim)] Else [HDD = 0] where Tim is the mean air temperature of day i. Examples: If the daily mean air temperature is 12°C, for that day the value of the HDD index is 6 (18°C-12°C). If the daily mean air temperature is 16°C, for that day the HDD index is 0.
Cooling degree days (CDD) index: the severity of the heat in a specific time period taking into consideration outdoor temperature and average room temperature (in other words the need for cooling). The calculation of CDD relies on the base temperature, defined as the highest daily mean air temperature not leading to indoor cooling. The value of the base temperature depends in principle on several factors associated with the building and the surrounding environment. By using a general climatological approach, the base temperature is set to a constant value of 24°C in the CDD calculation. If Tm ≥ 24°C Then [CDD = ∑iTim - 21°C)] Else [CDD = 0] where Tim is the mean air temperature of day i. Examples: If the daily mean air temperature is 26°C, for that day the value of the CDD index is 5 (26°C-21°C). If the daily mean air temperature is 22°C, for that day the CDD index is 0.
These calculations are executed on a daily basis, added up to a calendar month and subsequently to calendar years.
Direct access to
Database
- Energy (nrg), see:
Cooling and heating degree days by country - annual data (nrg_chdd_a)
Cooling and heating degree days by country - monthly data (nrg_chdd_m) Cooling and heating degree days by NUTS 2 regions - annual data (nrg_chddr2_a) Cooling and heating degree days by NUTS 2 regions - monthly data (nrg_chddr2_m)
Dedicated section
Methodology
- Energy statistics - cooling and heating degree days (ESMS metadata file — nrg_chdd)