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For more information on this release:
E-mail: environment@cso.ie John Golden (+353) 1 4984218 Linh Nolan (+353) 1 4984209
For general information on CSO statistics:
information@cso.ie (+353) 21 453 5000 Visit StatCentral.ie, the portal to Ireland's official statistics On-line ISSN 2009-7441
CSO statistical release, 25 July 2017, 11am

Domestic Building Energy Ratings

Quarter 2 2017

% of row 
Dwelling Type (2009-2017)Energy Rating Total
A-BCDEF-G
Apartment29292011114,378
Ground-floor apartment123126181339,675
Mid-floor apartment3036218648,062
Top-floor apartment142727161641,055
Basement Dwelling417162240201
Maisonette21342310127,226
House15412491237,743
Detached house1237251115186,195
Semi-detached house1041271210183,837
End of terrace house103624141650,577
Mid-terrace house133723131499,981

Basement dwellings are least energy efficient

Figure 1 BER Ratings by Type of Dwelling (2009 - 2017)
go to full release

A total of 23,585 Building Energy Rating (BER) audits were conducted on dwellings in the second quarter of 2017, bringing the cumulative total of BER audits conducted since January 2009 to 768,788 (see Table 1). The number of BER audits carried out in Q2 2017 represents an increase of 3% on the total number of BER audits since Q1 2017. 

Basements were by far the least energy efficient dwellings with the highest combined "F" and "G" rating of 40% and lowest combined "A" and "B" rating of 4% (see Table 3). In contrast, only 6% of mid-floor apartments received either an "F" or "G" rating, while 30% received a "B" rating or higher.

Detached and semi-detached houses were the most common dwelling types to be audited since 2009, each representing about 26% of the total number of audits (see Table 3). They also had similar energy ratings with approximately 50% of each dwelling type receiving a rating of “C” or higher. 

Dublin County had the highest combined “A” and “B” rating at 22% (see Table 4). In contrast, Offaly had the highest proportion of combined “F” and “G” rating at 20%.

Dublin 18, with an average dwelling age of 17 years, had the highest proportion of combined “A” and “B” rating at 38% (see Table 5). In contrast, Dublin 7 had the highest proportion of combined “F” and “G” rating at 27%, with an average dwelling age of 56 years.

Overall, Heating Oil and Mains Gas were the two most prevalent main space heating systems accounting for 78% of all dwellings audited (39% each), followed by Electricity at 15% (see Table 6). Of the dwellings using Mains Gas, 20% were rated “A” or “B”, compared with 9% for those using Heating Oil. Of the dwellings built since 2010, the majority used Mains Gas (58%), followed by Electricity (24%) and Heating Oil (16%) (see Table 9).

Approximately 61% of basements used Electricity, followed by Mains Gas at 26% (see Table 10). Electricity and Mains Gas were also used in most apartments that were audited. In contrast, 71% of detached houses used Heating Oil. 

Detached houses at 156 square metres had the highest average floor area (see Table 11). Dwellings constructed in the period 1900-1929 had the highest average primary energy use (408 kWh/m2/year), as well as, average carbon dioxide emissions (101 kgCO2/m2/year) (see Tables 12 and 13).

Table 14 examines dwellings that have had more than one BER audit carried out. The earliest assessment indicated that only 6% of dwellings received either an “A” or “B” rating compared with 17% in the most recent assessment. In addition, 21% of dwellings were originally rated “F” or "G" compared with only 5% in the latest assessment (see Table 14 and Figure 2).

EarliestLatest
A00
B101
B214
B3412
C1717
C2916
C31114
D11312
D21410
E1105
E283
F93
G122
ABCDEFG
01 Mains Gas2174422942
02 Heating Oil0943281155
03 Electricity33163121818
04 Solid Fuel02419271633
05 LPG1245116522
National11137251257

Table 15 examines the representativeness of dwellings that have a BER rating. The data were weighted up to national level using Census of Population 2011 figures. The national level data shows that 46% of dwellings would have received a rating of “C” or higher compared with 50% of dwellings in the actual BER data (see also Figure 3). In addition, 15% of dwellings would have received "F" or "G" ratings at the national level, whereas actual BER data indicates this figure to be 12%.

National DataBER database
A22
B111
B223
B367
C11011
C21213
C31313
D11313
D21212
E177
E265
F65
G97
ABCDEFG
Carlow11040261157
Cavan01143211158
Clare0838271458
Cork City11336241358
Cork County1164121948
Donegal0943241158
Dublin 01-2421232261577
Dublin County51437251144
Galway City0635321565
Galway County1940251258
Kerry11137261358
Kildare41141261045
Kilkenny11038261159
Laois01239221269
Leitrim08382312711
Limerick City0540301267
Limerick County1840281257
Longford0935261379
Louth1144323946
Mayo17372712610
Meath2124522945
Monaghan11136271258
Offaly06332218911
Roscommon07412212612
Sligo1934261569
Tipperary06352714711
Waterford City1838311246
Waterford County1939291156
Westmeath010372512610
Wexford1738281358
Wicklow31036241368
National11137251257
Table 1 Domestic Building Energy Ratings Certificates (2009-2017) 1
number
Period200920102011201220132014201520162017Total
January4,1024,6728,5636,5256,9687,0066,5215,2525,81355,422
February6,3215,6159,0236,3068,5247,5407,6596,8636,90464,755
March8,7676,1548,9396,5118,2088,3857,2627,5347,74369,503
April8,0385,4837,7814,4418,2988,7337,5887,3937,21664,971
May7,9235,4758,8765,8758,6458,7287,7147,9548,40469,594
June8,7295,7637,4634,8647,2638,2188,0017,4467,96565,712
July8,7775,9697,2585,5357,0969,3967,6766,557 58,264
August7,2686,4337,5315,0456,9738,1647,6497,028 56,091
September7,5207,4278,8564,9738,2819,9198,3587,671 63,005
October6,5888,4229,5686,6918,98010,7729,2207,936 68,177
November6,97611,6179,6208,8099,60610,8988,4169,031 74,973
December6,3468,0179,4806,3676,9387,7807,3126,081 58,321
           
Total87,35581,047102,95871,94295,780105,53993,37686,74644,045768,788
1 Includes all Certificates for Dwellings
Table 2 BER Ratings by Period of Construction (2009-2017)
% of row 
Period of ConstructionEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
1700-18990012234710910143818,054
1900-19290012234710910143737,988
1930-194900134579121010132634,185
1950-1966001356811141111131753,274
1967-197700136912161711109870,415
1978-198200138131518181065347,744
1983-19930014913162018954378,222
1994-199900151015192115753184,674
2000-200400171622221594321128,051
2005-200913112123179642110124,591
2010-201767169521100000021,732
               
Total213711131313127557698,930
Table 3 BER Ratings by Type of Dwelling (2009-2017)
% of row 
Dwelling TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Apartment14111312710101065564,378
Ground-floor apartment113810101012141076739,675
Mid-floor apartment251112121212129533348,062
Top-floor apartment1148109912149651041,055
Basement Dwelling2254888129931201
Maisonette12711131110111364487,226
House12391214141311544837,743
Detached house2127111313131165610186,195
Semi-detached house311511151615127555183,837
End of terrace house31151013131311767950,577
Mid-terrace house21281313111211766899,981
               
Total213711131313127557698,930
– No dwelling received this BER rating for this dwelling type
Table 4 BER Ratings by County (2009-2017)
% of row  
CountyEnergy Rating Average age
AB1B2B3C1C2C3D1D2E1E2FGTotal
Carlow1127121414151165579,74229
Dublin 01-24324710111113128667153,90236
Dublin County82481113121311644449,46227
Kildare51371214151411543527,65924
Kilkenny11271213131412755911,64934
Laois1128111514129666911,03329
Longford0127111212151276796,04427
Louth2239141514139644618,80332
Meath4138141615139544521,93625
Offaly1114912121111999119,52433
Westmeath013710121514116561013,20230
Wexford1125914151513855823,17928
Wicklow41271113131311756819,96932
Clare1026913151512865819,51031
Cork City12481212111212866717,68144
Cork County214111514121110544763,06832
Kerry11371113131412755823,39928
Limerick City10141113151614756711,37536
Limerick County10261114151413755721,41431
Tipperary01159121314138671123,62039
Waterford City2125111315171475467,43735
Waterford County21261113141513745711,44634
Galway City1125912161714866510,40924
Galway County11261114151311765830,16927
Leitrim00261214131210667115,38430
Mayo11258131514137561019,10631
Roscommon00151114161210756128,39031
Sligo1127912131313966911,83930
Cavan1138141612129655910,58827
Donegal11261315141311655821,04928
Monaghan1128131112141375586,94234
                
Total213711131313127557698,93032
Table 5 BER Ratings by Dublin Postal District (2009-2017)
% of row  
CountyEnergy Rating Average age
AB1B2B3C1C2C3D1D2E1E2FGTotal
Dublin 1226791011131386586,72730
Dublin 2146781012131286673,75536
Dublin 3102688911129911146,60454
Dublin 411479910131397878,36943
Dublin 5112579111614109866,40443
Dublin 62135678111310910166,81757
Dublin 6W312688913138910103,60949
Dublin 700136991213101011178,96356
Dublin 8036878912138781111,10343
Dublin 93036810101113108997,89445
Dublin 1024131513121187782,84942
Dublin 1122712121111111065658,52930
Dublin 1201246891213101012127,30652
Dublin 1351512111211121176545,02829
Dublin 1433588910121397767,34837
Dublin 15825101315141511422115,58417
Dublin 165148111412141375426,67927
Dublin 17517914191413842213,77124
Dublin 18471215161299832217,81317
Dublin 2044898881313107541,76530
Dublin 22101391314181996335,23426
Dublin 2431251115151614754211,74922
                
Total324710111113128667153,90236
– No dwelling received this BER rating in this postal district
Table 6 BER Ratings by Main Space Heating Fuel (2009-2017)
% of row  
Fuel TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Mains Gas325101516141295442269,462
Bulk LPG2261721181396321110,077
Bottled LPG0138131412121254510875
Heating Oil012612151615126555269,791
Electricity51113681317129817101,117
Coal00011413151418343,568
Smokeless Fuel00001313151418364,785
Peat0001311121317421,452
Wood Pellets & Chips3611201315117532221,238
Wood Logs42232348129101132588
Solid Multi-Fuel00000127131414163327,183
               
Total213711131313127557690,136
– No dwelling received this BER rating for this main space heating fuel type
Table 7 BER Ratings by Main Water Heating Fuel (2009-2017)
             % of row 
Fuel TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Mains Gas325101516141295442267,901
Bulk LPG2261721181396321110,033
Bottled LPG003814151311126459950
Heating Oil012612151615126555267,742
Electricity41113581316119819106,444
Coal0001112514161519273,445
Smokeless Fuel0011414171620284,274
Peat0011411131317401,483
Wood Pellets & Chips3612201414117532321,236
Wood Logs32143351013991128539
Solid Multi-Fuel00000128141514162926,089
               
Total213711131313127557690,136
– No dwelling received this BER rating for this main water heating fuel type
Table 8 Main Space Heating Fuel by County (2009-2017)
% of row  
CountyFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
Carlow364610629,735
Dublin 01-247362010148,802
Dublin County7712101048,173
Kildare4738113127,549
Kilkenny295298211,602
Laois3145716111,008
Longford262191435,981
Louth553653118,580
Meath424493121,918
Offaly105592519,419
Westmeath14541514313,161
Wexford1701512323,075
Wicklow4341105119,865
Clare12591511319,470
Cork City729162017,499
Cork County4041134262,699
Kerry1641910523,272
Limerick City5520204011,242
Limerick County2849149121,332
Tipperary1365911123,543
Waterford City621420307,421
Waterford County2354157211,390
Galway City1940336210,332
Galway County767167330,088
Leitrim066161265,382
Mayo373139319,070
Roscommon47211938,389
Sligo163219511,820
Cavan968108510,519
Donegal08196420,895
Monaghan8738736,905
       
Total39391562690,136
Table 9 Main Space Heating Fuel by Period of Construction (2009-2017)
% of row  
Period of ConstructionFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
1700-189929382210117,625
1900-192930391910137,477
1930-1949433899134,098
1950-1966464166153,128
1967-1977385147169,774
1978-1982365248147,541
1983-19933446118277,767
1994-19993338225184,151
2000-200439361942127,265
2005-200947301824121,030
2010-20175816241220,280
       
Total39391562690,136
Table 10 Main Space Heating Fuel by Type of Dwelling (2009-2017)
% of row 
Dwelling TypeFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
Apartment46447124,123
Ground-floor apartment477431237,905
Mid-floor apartment401580144,305
Top-floor apartment423531239,145
Basement Dwelling26106121183
Maisonette53737227,139
House187055337,723
Detached house1571562186,047
Semi-detached house4739571183,570
End of terrace house592587150,395
Mid-terrace house602297199,601
       
Total39391562690,136
Table 11 Average Floor Area by Period of Construction and Type of Dwelling (2009-2017)
m2
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-18996954465654106148158146115105119
1900-19296450445343901191241209790100
1930-1949516145515377110120110848298
1950-19667063545658661161251138886104
1967-197766655956108641321391088584109
1978-19826465645510066137142968482109
1983-1993585855575871147149958281109
1994-19996763586761761531611018383110
2000-20047471697768891661771039591114
2005-200981727278939517019010610198111
2010-20178179748086107195208126124117139
             
All7667667059861471561059189110
Table 12 Average Primary Energy Use by Period of Construction and Type of Dwelling (2009-2017)
kWh/m2/year
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-1899432421386489404479418409383418366401
1900-1929480430438502378450413420388418378408
1930-1949363352284422460445376401345368329364
1950-1966415333297394515321337354309340303328
1967-1977387315257360311309290299284283257287
1978-1982335287241292309304245252256247224250
1983-1993346303256300314282228234245248225240
1994-1999283279240281271260206209230251228225
2000-2004253241206241272212189193213219195205
2005-2009170188161192189164152162176172157168
2010-201712392769513293998065676574
             
All222250198257329234233243239260253242
Table 13 Average Carbon Dioxide Emissions by Period of Construction and Type of Dwelling (2009-2017)
kgCO2/m2/year
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-1899101968511186113107105931008699
1900-19291149897113831071071099410088101
1930-1949858161931001039610482857689
1950-19669974638511368859070776978
1967-1977927154787771737466666069
1978-1982816552647771616361575261
1983-1993836957686964565858585258
1994-1999666353636158515153585153
2000-2004585345526045464750494348
2005-2009364034403734363941383438
2010-2017251915193019231813131316
            
All505543567151586056605857
Table 14 Dwellings with Multiple BER Ratings (2009-2017)
                 % of total 
Earliest YearLatest YearTotal
A1A2A3B1B2B3C1C2C3D1D2E1E2FG
A1000
A20000
A30000000
B1000000000
B20000000000001
B30002100000004
C100023100000007
C200023210000009
C3000133210000011
D10000123321000013
D20000122232100014
E10000111122100010
E2000011111111008
F000011111111109
G0000111111111212
                 
Total000141217161412105332100
– No dwelling received this BER rating combination for the earliest and latest assessments
Table 15 BER Ratings Weighted to National Level (2009-2017)
             % of row  
Dwelling TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Apartment226911111011117559164,443
Detached house1127101213131265611675,637
Semi-detached house211510141516137666434,320
Terraced house1116101212121287810262,606
               
Total2126101213131276691,537,006

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 698,930 unique domestic BERs (one per dwelling) completed in the period 2009 to the end of June 2017. This compares with around 1.66 million occupied private households enumerated in the 2011 Census of Population. The 2011 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 2011 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 2009-2017 only the most recent BER was used. Around 7% 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 A. 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 A: 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 2017; 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. 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 Census 2011 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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