Domestic Building Energy Ratings Quarter 3 2026

Introduction

A Building Energy Rating (BER) is an indication of the energy performance of a dwelling (represented in units of kWh/m²/year). Actual energy performance will depend on how the occupants operate the dwelling. A BER is based on the characteristics of major components of the dwelling including: wall, roof and floor dimensions; window and door sizes and orientations, as well as the construction type and insulation, ventilation and air tightness features; the system for heat supply (including renewable energy), distribution, and control; and the type of lighting. The BER certificate indicates the annual primary energy usage and carbon dioxide emissions associated with the provision of space heating, water heating, ventilation, lighting, and associated pumps and fans. The energy use is calculated on the basis of a notional family with a standard pattern of occupancy - hence data in this release giving average primary energy use or carbon dioxide emissions are not based on actual data. A BER only covers electricity used for heating, lighting and ventilation with associated pumps and fans. Electricity used for cooking, refrigeration, laundry and other appliance use are not included.

Since 1st January 2009, a BER certificate and advisory report is compulsory for all homes being sold or offered for rent. A BER is also required for new dwellings that apply for planning permission on or after 1st January 2007. A BER certificate is required to avail of the grants for energy-efficiency improvements to the home that are provided under the Better Energy Homes scheme.

On 24 May 2026 the Building Energy Rating (BER) scale was modified in line with new EU wide regulations under the Energy Performance of Buildings Directive (EPBD). BERs awarded before 24 May 2026 will remain valid for ten years and are included in the tables of this release. For details on how these changes affect the tables in this release, please refer to the section on definitions below.

Access to Microdata

Further information on the BER scheme, including the changes made to the rating scale in 2026 and a microdata research file, is available on the Sustainable Energy Authority of Ireland website.

Revisions

The figures will be updated on a quarterly basis. While the changes to previous quarters will mainly relate to the most recent quarter, previous periods are also subject to revision mainly arising from some dwellings having another BER audit undertaken.

Coverage

There are three types of BER Certificates. A New Dwelling – Provisional BER is required for a dwelling that is not yet built but is offered for sale off the plans. A New Dwelling – Final BER is required for a newly-built dwelling before it is occupied. This certificate is based on data collected in a site survey carried out by a registered BER Assessor as well as drawings and specifications for the completed dwelling. An Existing Dwelling BER is required for any existing dwelling that is offered for sale or to let. An existing dwelling is one that has previously been sold or occupied. This is based on data collected in a site survey carried out by a registered BER Assessor. Both the New Dwelling – Final BER and the Existing Dwelling BER certificates are valid for 10 years from the date of issue. They become invalid if material changes are made to the dwelling during that period. This release is an analysis of Final and Existing BER certificates.

To ensure that all tables are consistent with each other, records that contain missing data in any of the main classification variables used in this release have been excluded e.g. missing response for county. Records with only the main space heating fuel or main water heating fuel information missing have been included except in tables using those variables.  

By the end of Q3 2026, 1,881,847 Final BERs had been published. Some of these represent dwellings with more than one rating in the period from January 2009 to September 2026. For each dwelling only the most recent is considered in the quarterly statistics published in this release.

National Representativeness

There were 1,407,196 domestic BERs (one per dwelling) completed in the period from January 2009 to the end of September 2026. This compares with around 1.9 million occupied private households enumerated in the 2022 Census of Population. The 2022 Census of Population included questions on county of location of the dwelling, the period when the dwelling was built, and the type of dwelling. These questions can be used to weight the BER data to national level. Table 9 in the Background Notes presents an initial weighting of BERs up to national level of non-vacant households using the 2022 Census of Population. The weights were calculated by dividing the number of non-vacant households in the Census by the number of unique BER households. In cases where a household had more than one BER carried out only the most recent BER was used. A stratum was classified as a unique combination of County (52 categories - Dublin postal districts were distinguished), period of construction (nine categories) and dwelling type (four categories). The BER contains more disaggregated dwelling types, e.g. mid-terrace house, but these had to be aggregated to correspond to the Census classification.    

In mid-2015 the Census and BER files were allocated Eircodes. This makes it possible to match both files at household level as postcodes are unique at letter-box level. This will create an opportunity to calculate weights in a more precise manner.

Non-domestic Buildings

Since 1st July 2008, a BER Certificate is required for all new non-residential buildings and from 1st January 2009 for all public service buildings and for existing non-residential buildings. The CSO publishes a quarterly release analysing this file.

Definitions

The BER rating scale is divided into categories from G (largest primary energy usage) to an A0 rating (lowest primary energy usage, with zero fossil fuel demand and carbon emissions). The kilowatt-hour is the unit of energy used in Dwelling Energy Assessment Procedure (DEAP). The BER is measured in kWh per square metre of floor area of the dwelling per year (kWh/m²/year).

On 24 May 2026 the Building Energy Rating (BER) scale was modified in line with new EU wide regulations under the Energy Performance of Buildings Directive (EPBD). The scale has been simplified from fifteen points to eight (A0, A, B, C, D, E, F, G).  

To allow data from both scales to be used together, ratings from the old scale have been converted directly to their equivalent letter in the new scale. Ratings for the two scales are described in Table A and Table B. The energy thresholds between ratings are identical for ratings of C and above in both scales. 

County is where the dwelling is located. NUTS 3 regions are based on county-level information.

Type of dwelling is selected from one of the following: Detached house; Semi-detached house; End of Terrace house; Mid-terrace house; Ground-floor apartment; Mid-floor apartment; Top-floor apartment; Basement apartment; and Maisonette. Some audit reports did not specify the type of house or apartment. All apartment types have been combined for the tables in this release.

Year of construction is the year when the dwelling was originally built.

The fuel used by the Main Space Heating system. The main space heating system heats the largest proportion of the dwelling. This proportion is calculated using a count of the habitable rooms. It often provides hot water as well as space heating. A group or district heating scheme refers to a heating system shared by multiple dwellings, which can combine multiple fuel types.

The Total Internal Floor Area of the dwelling is the total area of exposed and semi-exposed floors. It excludes any unheated areas that are thermally separated from the dwelling. The total energy usage is divided by the dwelling floor area to determine the Building Energy Rating.

A Heat Pump is defined as a renewable technology under Article 23 of the Renewable Energy Directive (2009/28/EC), where the heat source itself is renewable, and efficiency is at least higher than 100%. The specific threshold for efficiency under the directive varies by the efficiency of electricity production in a member state. In this release, heat pumps were identified by reference to the main space heating fuel being electricity and the efficiency being greater than 100%. Dwellings with heat pumps for water heating only are currently not included in these figures. 

The term Solar Energy here covers both solar thermal installations for water and space heating and solar photovoltaic installations for electricity generation. They are identified separately and combined, only counting dwellings with both thermal and photovoltaic installations once.

Table A: Building Energy Rating Categories (Rating before 24 May 2026)

Category	kWh/m2/year
A1	≤ 25
A2	≤ 50
A3	≤ 75
B1	≤ 100
B2	≤ 125
B3	≤ 150
C1	≤ 175
C2	≤ 200
C3	≤ 225
D1	≤ 260
D2	≤ 300
E1	≤ 340
E2	≤ 380
F	≤ 450
G	> 450

 

Table B: Building Energy Rating Categories (Rating after 24 May 2026)

Category	kWh/m2/year
A0	≤ 42*
A	≤ 75
B	≤ 150
C	≤ 225
D	≤ 275
E	≤ 325
F	≤ 375
G	> 375
* Also meets criteria for Zero Emission Building (ZEB) defined in directive.

Table Notes

The number of tables in the current release has been reduced from previous iterations as users can now make their own cross-tabulations with the open data tables available on data.cso.ie. Please see the Data page of the release for links to these. 

Table 1 in the main release gives the overall distribution of ratings from A0 to G for dwellings with a BER, using only the most recently published BER for each dwelling. 

Table 2 in the main release gives the number of BERs where active installations of renewable technologies like solar energy and heat pumps for space heating were recorded on the BER certificate. It should be noted that installations that were not funded by an SEAI grant may not have received a post-works BER, and as such will not appear in these data. 

Table 3 in the main release gives the number of BERs by the main space heating fuel over time by quarter. 

Table 4 in the main release gives the number of BERs by the main space heating fuel, crossed with the NUTS 3 region. County level data is available to users in the open data table EBQ03, accessible from the Data tab of the release. 

Table 5 in the main release shows the general impact of the age of the dwelling on the BER profile. The age bands used can be linked to changes in Building Regulations requiring homes to be more energy efficient. The number of BER certificates with a given year of construction should not be taken to represent the total number of new dwellings completed in that year. 

Table 6 in the main release gives the number of BERs by the main space heating fuel and period of construction. The change from fossil fuels to electricity over time can be seen. 

Table 7 in the main release profiles BER ratings by county and Dublin postal district. 

Table 8 in the main release cross classifies the average floor area by the energy rating and the type of dwelling. 

Table 9 in the Background Notes is an analysis of BER rated properties after they have been weighted to 2022 Census of Population level. It can be compared with the Total row profile in earlier tables. See the entry under National representativeness for more details.