Renewable energy technologies were present in almost a quarter of BER rated dwellings as of Q2 2025 (See Table A and Figure 1).
Solar energy was present in 14% of BER rated dwellings (See Table 13), while heat pumps were present in 13% (See Table 14). Dwellings with both represented 2% of households with a BER (See Table A and Figure 1).
By county, the highest proportion of dwellings with solar energy was 22% in Meath, 20% in Kildare and 20% in Dublin County (See Table 14).
A ratings were received by 99% of dwellings built since 2020, compared with 16% of all rated dwellings (See Figure 2 and Table 2).
The most common main space heating fuel in audited dwellings was mains gas (36%), followed by heating oil (35%) and electricity (24%). For dwellings built since 2015, electricity was the most common space heating fuel (See Figure 3 and Table 9).
By county, the highest proportions of A rated dwellings were in Kildare (28%), Meath (26%) and Dublin County (26%), while the lowest were in Leitrim and Cork City (both 5%) (See Table 4).
Solar energy in this release covers both solar thermal installations for water and space heating and solar photovoltaic installations for electricity generation.
It should be noted that the actual number of renewable installations will likely be higher than the figures contained in this release as only dwellings which have received a BER certificate are included in this report, which does not cover the full housing stock.
If a dwelling has a BER certificate, solar energy and heat pumps can be installed without the need for a new assessment, which would also not count towards the figures presented here.
Please refer to the Background Notes for more details on definitions and coverage.
Of the BER rated households where the main space heating fuel can be identified, over 300,000, or 24%, had at least one source of renewable energy present when considering heat pumps, solar thermal systems, and solar photovoltaic panels. The proportion of rated dwellings with both a heat pump and solar energy was 2%.
Newer builds are more likely to include heat pump installations, which were present in 86% of dwellings built in 2020-2025. Solar installations outnumber heat pump installations in dwellings built before 2020 (See Table A and Figure 1).
For further breakdown of these percentages by county and type of dwelling, please refer to Tables 13 and 14.
| X-axis label | Heat Pump | Solar Energy | Both | Neither |
|---|---|---|---|---|
| 1700-1949 | 4259 | 10991 | 1582 | 148239 |
| 1950-1977 | 5673 | 20866 | 2190 | 183795 |
| 1978-1993 | 4707 | 22257 | 1871 | 161004 |
| 1994-1999 | 3420 | 13442 | 956 | 111100 |
| 2000-2004 | 4467 | 17110 | 1783 | 178639 |
| 2005-2009 | 5623 | 17549 | 3494 | 160888 |
| 2010-2014 | 1248 | 8219 | 1319 | 3790 |
| 2015-2019 | 22045 | 27234 | 5491 | 2225 |
| 2020-2025 | 80376 | 9141 | 8913 | 5949 |
| Table A: Percentage of BERs with Renewable Energy Installations by Period of Construction | |||||
| % of row | |||||
| Period of Construction | Solar Energy | Heat Pump | Both | Neither | Total |
| 1700-1949 | 7 | 3 | 1 | 90 | 165,071 |
| 1950-1977 | 10 | 3 | 1 | 86 | 212,524 |
| 1978-1993 | 12 | 2 | 1 | 85 | 189,839 |
| 1994-1999 | 10 | 3 | 1 | 86 | 128,918 |
| 2000-2004 | 8 | 2 | 1 | 88 | 201,999 |
| 2005-2009 | 9 | 3 | 2 | 86 | 187,554 |
| 2010-2014 | 56 | 9 | 9 | 26 | 14,576 |
| 2015-2019 | 48 | 39 | 10 | 4 | 56,995 |
| 2020-2025 | 9 | 77 | 9 | 6 | 104,379 |
| Total | 12 | 10 | 2 | 76 | 1,261,855 |
The number of domestic Building Energy Rating (BER) audits reported in April to June (Q2) 2025 was 42,032. This was 13% higher than the number published in Q2 2024, and the highest second quarter total for any year since 2009. In total, 1.7 million BER audits have been published from 2009-2025 (See Table 1).
A ratings were given to 99% of audited dwellings built between 2020-2025, and 94% of those built between 2015-2019. In comparison, 37% of dwellings built between 2010-2014 received an A rating, and 5% of those from 2005-2009 (See Figure 2 and Table 2).
Mid-floor apartments were the most energy efficient dwelling type proportionally, with 29% of those audited receiving an A rating. Basement dwellings had the highest proportion of G ratings (23%) by type of dwelling (See Table 3).
| A | B | C | D | E | F-G | |
| 1700-1977 | 3 | 8 | 20 | 23 | 18 | 28 |
| 1978-1999 | 3 | 14 | 41 | 29 | 9 | 5 |
| 2000-2004 | 2 | 20 | 56 | 17 | 4 | 1 |
| 2005-2009 | 5 | 41 | 45 | 7 | 2 | 0 |
| 2010-2014 | 37 | 55 | 6 | 1 | 0 | 0 |
| 2015-2019 | 94 | 6 | 0 | 0 | 0 | 0 |
| 2020-2024 | 99 | 1 | 1 | 0 | 0 | 0 |
| 2025-2029 | 99 | 0 | 1 | 0 | 0 | 0 |
The highest proportions of A rated dwellings were in Kildare (28%), Meath (26%) and Dublin County (26%), while the lowest were in Leitrim and Cork City (both 5%). The highest proportions of G rated dwellings were in counties Roscommon (11%) and Leitrim (11%) (See Table 4).
In the Dublin postal districts, the highest proportions of A ratings were in Dublin 18 (42%), Dublin 13 (31%) and Dublin 20 (28%). The highest level of G rating was 13% in Dublin 06 (See Table 5).
The most common main space heating fuel in audited dwellings was mains gas (36%), followed by heating oil (35%) and electricity (24%). For dwellings built since 2015, electricity was the most common space heating fuel. Dwellings constructed in 2020-2025 were 93% electrically heated (See Figure 3 and Table 9).
By county, heating oil was most frequently used in rated dwellings in Donegal (74%), Mayo (69%) and Roscommon (68%). The proportion of rated dwellings using electricity as the main space heating fuel was highest in Galway City (37%) and the Dublin postal districts (28%) (See Table 8).
| Mains Gas | Heating Oil | Electricity | |
| 2000-2004 | 40 | 37 | 20 |
| 2005-2009 | 43 | 32 | 20 |
| 2010-2014 | 41 | 34 | 21 |
| 2015-2019 | 44 | 5 | 50 |
| 2020-2025 | 7 | 0 | 93 |
The average floor area for all rated dwellings was 117 m2. The dwelling type with the largest average floor area was detached houses (166 m2) while the smallest type was apartments (70 m2) (See Table 12).
Energy from solar thermal systems or solar electric panels was present in 14% of rated dwellings. This proportion was highest in detached houses (22%) and lowest in apartments (4%) (See Table 13).
By county, the highest proportion of dwellings with solar energy was 22% in Meath, 20% in Kildare and 20% in Dublin County. The lowest proportion was 10% in each of Donegal, Leitrim and Longford (See Table 13).
A heat pump was present in 13% of rated dwellings where the main space heating fuel was identifiable (See Table 14).
The proportion of ratings with heat pumps present was highest in newer builds, accounting for 48% of dwellings built in 2015-2019 and 86% of those built in 2020-2025.
By county, this proportion was highest in Kildare (21%) and Wicklow (21%), and lowest in Leitrim (6%) and Cavan (7%) (See Table 14).
In dwellings which have received more than one BER assessment, over 188,000 saw an improvement of at least one full letter over their initial energy rating.
Of these, 49% improved from a C rating or below in their first rating to an A or B in their most recent assessment (See Table 15).
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Statistician's Comment
The Central Statistics Office (CSO) has today (24 July 2025) published Domestic Building Energy Ratings for Quarter 2 (Q2) 2025.
Commenting on the release, Kevin Hunt, Statistician in the Climate and Energy Division, said: "This release for Q2 2025 is the first time that renewable technologies have been included in the CSO’s quarterly series on Domestic Building Energy Ratings (BER). Installations of heat pumps or solar energy systems were present in more than 300,000 BER rated dwellings, accounting for almost a quarter (24%) of the rated stock (See Table A and Figure A).
Proportion of Rated Dwellings with Solar Energy
Energy from solar thermal collectors or solar electric panels was present in 14% of rated dwellings. This proportion was highest in detached houses (22%) and lowest in apartments (4%) (See Table 13).
By county, the highest proportion of dwellings with solar energy was 22% in Meath, 20% in Kildare and 20% in Dublin County. The lowest proportion was 10% in each of Donegal, Leitrim and Longford (See Table 13).
Proportion of Rated Dwellings with Heat Pumps
A heat pump was present in 13% of rated dwellings where the main space heating fuel was identifiable (See Table 14).
The proportion of ratings with heat pumps present was highest in newer builds, with heat pumps in 48% of dwellings built between 2015-2019 and 86% of those built from 2020 up to Q2 2025 (See Table 14).
Energy Ratings by Period of Construction
Of the 1.3 million unique dwellings to receive an audit since 2009, 16% received an A rating in their most recent audit, 16% a B rating, and 32% a C rating (See Table 2). Newer builds had higher energy ratings than older stock. A ratings were given to 99% of audited dwellings built between 2020-2025, and 94% of those built between 2015-2019. In comparison, 37% of dwellings built between 2010-2014 and 5% of the dwellings built from 2005-2009 received an A rating (See Figure 2 and Table 2).
Main Space Heating Fuel
The most common main space heating fuel in audited dwellings was mains gas (36%), followed by heating oil (35%) and electricity (24%). For dwellings built since 2015, electricity was the most common space heating fuel. Dwellings constructed from 2020 to Q2 2025 were 93% electrically heated (See Figure 3 and Table 9).
Local Area Analysis
The highest proportions of A rated dwellings were in Kildare (28%), Meath (26%) and Dublin County (26%), while the lowest were in Leitrim and Cork City (both 5%). The highest proportions of G rated dwellings were in counties Roscommon (11%) and Leitrim (11%) (See Table 4).
In the Dublin postal districts, the highest proportions of A ratings were in Dublin 18 (42%), Dublin 13 (31%) and Dublin 20 (28%). The highest level of G rating was 13% in Dublin 06 (See Table 5).
Dwelling Type and Floor Area
The average floor area for all rated dwellings was 117 m2. The dwelling type with the largest average floor area was detached houses (166 m2) while the smallest type was apartments (70 m2) (See Table 12).
Mid-floor apartments were the most energy efficient dwelling type proportionally, with 29% of those audited receiving an A rating. Basement dwellings had the highest proportion of G ratings (23%) by type of dwelling (See Table 3).