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For more information on this release:
E-mail: environment@cso.ie Dympna Corry Berna Lawlor
For general information on CSO statistics:
information@cso.ie (+353) 21 453 5000 On-line ISSN 2009-7441
CSO statistical release, , 11am

Domestic Building Energy Ratings

Quarter 2 2021

Table A: Number of Domestic BER certificates 
number 
Period20172018201920202021% change 2021/2020
April7,1407,0537,2461,9966,439223%
May8,1768,3948,3322,4497,991226%
June7,6897,5917,5705,7957,90636%
       
Quarter 223,00523,03823,14810,24022,336118%

118% increase in Domestic BER audits in April-June 2021

Figure 1: Number of Domestic BER Certificates published in 2019-2021
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There were 22,336 Building Energy Rating (BER) audits reported in quarter two 2021 compared with 10,240 in quarter two 2020 (see Table A, Table 1 and Figure 1). This is an increase of 118% (see Information Note). April 2021 was 223% higher than April 2020. May 2021 was a similar 226% above May 2020. There was an increase in June 2021 when the number of completed BER audits was 36% above the number in June 2020. In the period 2009 to June 2021 just over 1.1 million BER audits have been undertaken (see Table 1).

Dwellings built in 2015-2021 were considerably more energy efficient than those built in earlier periods with 97% given an “A” rating compared with 34% in 2010-2014 and 1% in 2005-2009 (see Table 2 and Figure 4).

Dublin County had the highest combined “A” and “B” rating at 32% (see Table 4). Roscommon had the lowest proportion of combined “A” and “B” rating at 10%.

Dublin 18, with an average dwelling age of 18 years, had the highest proportion of combined “A” and “B” rating at 45% (see Table 5). The average age of dwellings in Dublin 15 that have had a BER audit done was 17 years, but the combined "A" and "B" rating was much lower at 32% than in Dublin 18. The highest proportion of combined “F” and “G” rating was 25% for Dublin 7.

Electricity was the main space heating fuel used in 52% of the dwellings completed during 2015-2021 and with a BER audit. This was an increase from 2000-2004 when 19% of dwellings with a BER audit used electricity. There was a contrasting trend for heating oil with 35% of 2000-2004 built dwellings using heating oil compared with 4% for dwellings built in 2015-2021 (see Table 9).

The average floor area of all dwellings with a BER audit was 112 square metres (see Table 11). This average size varied from 159 square metres for detached houses to 60 square metres for basement dwellings.

Table 14 examines dwellings that have had more than one BER audit carried out. In their earliest assessment only 8% of dwellings received either an “A” or “B” rating compared with 24% in their most recent assessment. In contrast, 18% of dwellings were rated “F” or "G" in their first BER assessment compared with only 4% in their latest BER assessment (see Table 14 and Figure 2).

EarliestLatest
A03
B112
B225
B3514
C1818
C21015
C31212
D11411
D2138
E194
E273
F82
G102
Earliest BER ratingsLatest BER ratings
A00
B101
B214
B3412
C1717
C2916
C31213
D11412
D2149
E1105
E283
F93
G122

Table 15 examines the representativeness of dwellings that have a BER. The data were weighted up to national level using 2016 Census of Population figures. The national level data shows that 6% of dwellings in Ireland would have received a rating of “F” compared with 5% of dwellings that have had a BER assessment (see also Figure 3). Similarly, 8% of dwellings would have received a rating of "G" compared with 7% of dwellings in the actual BER data. In contrast, 6% of dwellings would have received an "A" rating at the national level, whereas 8% of dwellings that have had a BER assessment were given an "A" rating.

National DataBER Database
A68
B111
B233
B378
C11012
C21213
C31212
D11212
D21110
E166
E255
F65
G87
National DataBER database
A23
B111
B223
B367
C11011
C21213
C31313
D11313
D21211
E177
E265
F65
G97

1Dwellings with BERs have been weighted using 2016 Census of Population data to estimate a BER profile for All Dwellings at National level (see Background Notes).

ABCDEF-G
1700-19771519242032
1978-1999074134125
2000-2004011612152
2005-200913651931
2010-201434567100
2015-20219720000
Table 1 Domestic BER Certificates (2009-2021) 1
number
Period2009201020112012201320142015201620172018201920202021Total
January4,1104,6898,5746,5306,9747,0096,5265,2615,6875,1755,5225,8823,84075,779
February6,3325,6419,0366,3128,5297,5457,6636,8676,8156,4996,8877,6194,93090,675
March8,7686,1678,9446,5188,2098,3867,2687,5437,6316,5177,2157,1716,16196,498
April8,0625,4857,7804,4458,2988,7367,5917,3987,1407,0537,2461,9966,43987,669
May7,9325,4768,8785,8818,6488,7297,7167,9538,1768,3948,3322,4497,99196,555
June8,7355,8027,4654,8647,2658,2158,0027,4477,6897,5917,5705,7957,90694,346
July8,7765,9477,2605,5367,1029,3987,6756,5617,1247,5108,3517,609 88,849
August7,2646,4247,5325,0456,9748,1667,6477,0317,2517,1558,2266,891 85,606
September7,5097,4228,8484,9658,2789,9218,3567,6687,9727,2298,4078,775 95,350
October6,5838,3959,5646,6878,97510,7699,2227,9288,0578,31210,8108,398 103,700
November6,95711,5939,6108,7979,59810,8928,4019,0128,3948,2646,1808,068 105,766
December6,3278,0069,4676,3626,9307,7737,3096,0775,6795,7406,2606,473 82,403
               
Total87,35581,047102,95871,94295,780105,53993,37686,74687,61585,43991,00677,12637,2671,103,196
1 Includes all Certificates for Dwellings
Table 2 BERs by Period of Construction (2009-2021)
% of row 
Period of ConstructionEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
1700-18990012335710910143724,467
1900-19291012345710910143653,354
1930-19491013567912910132445,496
1950-1966112356811141110121670,832
1967-19771014791115161199889,845
1978-19820014913151817964358,012
1983-199300151013161917854297,350
1994-1999011611161919136431106,306
2000-200400291822201373210167,733
2005-200913112224179642110156,625
2010-20143428181142111000011,756
2015-20219711000000000067,789
               
Total813812131212106557949,565
Table 3 BERs by Type of Dwelling (2009-2021)
% of row 
Dwelling TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Apartment151214117910966573,589
Ground-floor apartment61371011111213865752,333
Mid-floor apartment1041012121211107432364,305
Top-floor apartment514810101012138551053,908
Basement Dwelling603275686109929302
Maisonette1027111211101010533710,613
House12391214141211544834,361
Detached house6138111212121065510261,944
Semi-detached house1112612151413105444259,139
End of terrace house111261112111110656872,492
Mid-terrace house813913121011107557136,579
               
Total813812131212106557949,565
Table 4 BERs by County (2009-2021)
% of row  
CountyEnergy Rating Average age
AB1B2B3C1C2C3D1D2E1E2FGTotal
Carlow61271215131310545712,66530
Dublin 01-24914810111112117556213,79337
Dublin County18248111211119533371,29427
Kildare17138121313119433441,51923
Kilkenny51371213121211645815,28935
Laois4139121513118555814,49330
Longford2227121312141065697,96429
Louth9239161411108534627,28931
Meath1713915151197333435,55523
Offaly412510131210108781112,44734
Westmeath31371013141310655917,09232
Wexford51251013141411755730,79830
Wicklow121371112111110655727,87932
Clare3126913141412765823,87233
Cork City32491212111211766722,44645
Cork County8241114131199544786,09533
Kerry42371112131311755830,12730
Limerick City41271414141311645616,84537
Limerick County41261113141312654724,62232
Tipperary212610121213127671130,33240
Waterford City61261314141511644510,71536
Waterford County72371212131312644614,47935
Galway City61261013151512654414,72625
Galway County51371114141210655837,10229
Leitrim1127121412119667127,13033
Mayo41259131513126561025,16233
Roscommon21251114141197561211,31433
Sligo31271013121312766914,62232
Cavan2139151512119545913,96729
Donegal31261315141210655828,93330
Monaghan6238121111131164588,99935
                
Total813812131212106557949,56532
Table 5 BERs by Dublin Postal District (2009-2021)
% of row  
Dublin Postal DistrictEnergy Rating Average age
AB1B2B3C1C2C3D1D2E1E2FGTotal
Dublin 1625791011121385578,61832
Dublin 2925791111131075464,99034
Dublin 3413689101012989128,74257
Dublin 44148910111313867710,86445
Dublin 5412581011141398858,96744
Dublin 661356781113979158,98559
Dublin 6W101268810121287885,13149
Dublin 720237109121299101511,95959
Dublin 84258891012128671014,75347
Dublin 9110378991112878711,44944
Dublin 104025131512121076764,11146
Dublin 1172612131111109655411,85631
Dublin 124125791012139910910,69554
Dublin 132025101010910954438,05426
Dublin 141035899101112866510,03638
Dublin 15171410141512118321122,76617
Dublin 1612149111312131154329,34328
Dublin 175161015191412842214,36126
Dublin 1814511151512986221110,88818
Dublin 208369889121396542,37232
Dublin 227014101415161584327,80127
Dublin 24141261114131311643117,05222
                
Total914810111112117556213,79337
Table 6 BERs by Main Space Heating Fuel (2009-2021)
% of row  
Fuel TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Mains Gas825111615121184332371,685
Bulk LPG2261721181385222112,963
Bottled LPG0139131412111255591,059
Heating Oil112712151514126555343,229
Electricity23212357111286513162,528
Coal00011411141419363,257
Smokeless Fuel000001412141316406,323
Peat0011410131217401,523
Wood Pellets & Chips2410191416127632321,539
Wood Logs422333410121091028624
Solid Multi-Fuel00000127131313153631,118
               
Total713812131212106557935,848
– No dwelling received this BER for this main space heating fuel type
Table 7 BERs by Main Water Heating Fuel (2009-2021)
             % of row 
Fuel TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Mains Gas825111615121184332369,775
Bulk LPG2261721181285222112,919
Bottled LPG0139141512101265581,167
Heating Oil112712151514126555340,440
Electricity22212357111286615170,150
Coal0001112613141519283,127
Smokeless Fuel00011514151518305,459
Peat0011510141318381,546
Wood Pellets & Chips3411191315137632321,519
Wood Logs322333611121091024570
Solid Multi-Fuel00000127131414163129,176
               
Total713812131212106557935,848
– No dwelling received this BER for this main water heating fuel type
Table 8 Main Space Heating Fuel by County (2009-2021)
% of row    
CountyFuel Type 
Mains GasHeating OilElectricitySolid FuelLPGTotal
Carlow3545145112,656
Dublin 01-247252210205,568
Dublin County7511141068,926
Kildare4733172141,398
Kilkenny2949137215,227
Laois33441013114,458
Longford164201237,896
Louth573292126,992
Meath4836133135,530
Offaly11541321112,327
Westmeath14541712317,040
Wexford1681810330,669
Wicklow4237164127,560
Clare13571710323,827
Cork City729172022,293
Cork County3938174285,677
Kerry1622310529,950
Limerick City5819203016,707
Limerick County2649168124,544
Tipperary14631210130,245
Waterford City6014233010,689
Waterford County2053206214,414
Galway City2039344214,619
Galway County765187336,993
Leitrim167171057,127
Mayo371158225,102
Roscommon470149311,309
Sligo163228614,585
Cavan967127513,885
Donegal079116428,675
Monaghan107012638,960
 
Total40371751935,848
Table 9 Main Space Heating Fuel by Period of Construction (2009-2021)
% of row  
Period of ConstructionFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
1700-18992938239123,910
1900-192929392110152,601
1930-1949443899145,374
1950-1966473976170,555
1967-1977394956189,184
1978-1982365247157,762
1983-19933445127296,852
1994-199934382341105,654
2000-200441351932166,798
2005-200945311824152,831
2010-20145228161211,011
2015-2021434520063,316
       
Total40371751935,848
Table 10 Main Space Heating Fuel by Type of Dwelling (2009-2021)
% of row 
Dwelling TypeFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
Apartment49544113,380
Ground-floor apartment476441249,631
Mid-floor apartment390590157,717
Top-floor apartment412541251,145
Basement Dwelling25106013269
Maisonette526381210,457
House177145334,343
Detached house1568962261,733
Semi-detached house4935961258,752
End of terrace house6022125172,260
Mid-terrace house61211261136,161
       
Total40371751935,848
Table 11 Average Floor Area by Period of Construction and Type of Dwelling (2009-2021)
m2
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-18996853455650105147159149117106119
1900-19296349445341891201251239891101
1930-1949506145524774111121112858299
1950-19667163555765681171271158886105
1967-19776864605580651321401108685111
1978-1982656664569170138144988583111
1983-1993595854585771147150978381110
1994-19996663586868771541631028584112
2000-20047471697768881681781059792116
2005-200982727179879317219410710198113
2010-20148678717586100195219122117109147
2015-202180808188100109187197123117112127
 
All7667677160881481591089490112
Table 12 Average Primary Energy Use by Period of Construction and Type of Dwelling (2009-2021)
kWh/m2/year
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-1899434412380471400464414403368402358392
1900-1929489415409479397455413411373404363397
1930-1949362346273411458433372388332346314350
1950-1966424315262375397298335345297323291316
1967-1977379308252349339302289291276275250280
1978-1982330278236286290300243246248242218244
1983-1993346293245287337272227228235240218232
1994-1999281267230268246242205202218239218216
2000-2004257231198230235202188187203207186197
2005-2009167186162188178161151156172169154164
2010-201420911396120132951009985898596
2015-20211035847566750575352524952
             
All222232180241290207232229216232233225
Table 13 Average Carbon Dioxide Emissions by Period of Construction and Type of Dwelling (2009-2021)
kgCO/m2/year
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-189910292821058310810610488958496
1900-192911693891068610710710790968497
1930-19498479588999999510078797285
1950-19661017055808764858767726574
1967-1977916852747968737263635767
1978-1982796249617271616158565059
1983-1993836553638260565654554955
1994-1999665850585553504950544850
2000-2004594942485042464547454045
2005-2009363833393533363740373337
2010-2014472319243019232318181721
2015-20212011910131012111010910
  
All505038516244585650525353
Table 14 Dwellings with Multiple BERs (2009-2021)
                 % of total
Earliest YearLatest YearTotal
A1A2A3B1B2B3C1C2C3D1D2E1E2FG
A1000
A20000000
A300000000000
B100000000001
B200001100000002
B3000012100000005
C10000133100000008
C200000232100000010
C300000233210000012
D100000123321000014
D200000122222100013
E10000011112210009
E20000011111111007
F0000011111111108
G00000111111111110
  
Total01225141815121184322100
– No dwelling received this BER combination for the earliest and latest assessments
Table 15 BERs Weighted to National Level (2009-2021)
             % of row  
Dwelling TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Apartment826911111011106547166,491
Detached house5137101212121165611685,906
Semi-detached house712510131314127555442,018
Terraced house612610111112118779259,949
               
Total6137101212121165681,554,364

Background Notes

Domestic Building Energy Ratings

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.

Access to Microdata 

Further information on the BER scheme (including links to a microdata research tool) is available on the Sustainable Energy Authority of Ireland website at http://www.seai.ie/BER/ 

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. 

National representativeness  

There were 949,565 unique domestic BERs (one per dwelling) completed in the period 2009 to the end of June 2021. This compares with around 1.7 million occupied private households enumerated in the 2016 Census of Population. The 2016 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 15 presents an initial weighting of BERs up to national level of non-vacant households using the 2016 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 in the period 2009-2021 only the most recent BER was used. Around 8% of Census households were excluded because there were no BER households in the particular stratum e.g. detached houses in Dublin 1 that were constructed in the period 1919-1945. 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 A1 rating (lowest primary energy usage). 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). The full range of categories is described in Table B. For the purposes of this release A1, A2, and A3 have been combined together because of the small number of Certificates in these categories. 

Table B: Building Energy Rating Categories 

Category

kWh/m2/year

A1

≤ 25

A2

> 25

A3

> 50

B1

> 75

B2

> 100

B3

> 125

C1

> 150

C2

> 175

C3

> 200

D1

> 225

D2

> 260

E1

> 300

E2

> 340

F

> 380

G

> 450

 

County is where the dwelling is located. 

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. 

Year of construction is 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. 

The fuel used by the Main Water Heating system. This category has similar fuel response options to the Main Space Heating system. 

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. 

Table Notes  

Table 1 presents the number of Final and Existing BERs published by month since January 2009. A household that has had BERs conducted in different years is included in each year. This table gives an overview of the number of BER assessments being performed and will inform the user of changes since the previous quarterly analysis. 

Tables 2-13 only include the latest BER published for each dwelling from January 2009 to June 2021; hence the total number of BER certificates is lower than the total in Table 1.

Table 2 shows the general impact of the age of the dwelling on the BER profile. It can be linked with changes to the Building Regulations that require new homes to be more energy efficient. 

Table 3 shows how the BER profile varies by type of dwelling. 

Tables 4-5 profile BERs by county and Dublin postal district. Table 4 is in county within province order. 

Tables 6-7 profile BERs by main space and water heating fuels respectively. Records with a missing response for main space heating fuel have been excluded from Tables 6 and 8-10. Similarly records with a missing response for main water heating fuel have been excluded from Table 7. 

Table 8 cross-classifies county by main space heating fuel. Mains gas is not generally available in some counties. Some counties use local heating fuels such as peat e.g. County Offaly. 

Tables 9-10 cross-classify main space heating fuel by period of construction and dwelling type. 

Tables 11-13 cross-classify the average floor area, average primary energy use and average carbon dioxide emissions by period of construction and the dwelling type. The latter is more precisely defined in recent years but in the earlier years more general descriptions such as House were in use. It is not possible to reclassify these to detached, semi-detached, end-of-terrace or mid-terraced house. The average primary energy use and average carbon dioxide figures are notional figures based on assumed energy use factors and occupancy.

Table 14 is an analysis of properties that had BER audits carried out in more than one year. The earliest and latest BER ratings are cross-classified to show trends in energy savings arising from insulation, retrofitting etc.

Table 15 is an analysis of BER properties after they have been weighted to 2016 Census  of Population level. It can be compared with the Total row profile in Table 2. See the entry under National representativeness for more details.

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