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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 1 2021

Table A: Number of Domestic BER certificates 
number 
Period20172018201920202021% change 2021/2020
January5,6875,1755,5225,8823,887-34%
February6,8146,4996,8857,6194,961-35%
March7,6306,5177,2157,1705,996-16%
       
Quarter 120,13118,19119,62220,67114,844-28%

28% decrease in Domestic BER audits in January-March 2021

Figure 1: Number of Domestic BER Certificates published in 2019-2021
go to full release

There were 14,844 Building Energy Rating (BER) audits reported in quarter one 2021 compared with 20,671 in quarter one 2020 (see Table A, Table 1 and Figure 1). This is a decrease of 28% (see Information Note). January 2021 was 34% lower than January 2020. February 2021 was a similar 35% below February 2020. There was a pick-up in March 2021 when the number of completed BER audits was 16% below the number in March 2020. In the period 2009 to March 2021 just over one 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 31% (see Table 4). Roscommon had the lowest proportion of combined “A” and “B” rating at 9%.

Dublin 18, with an average dwelling age of 18 years, had the highest proportion of combined “A” and “B” rating at 44% (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 31% 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 51% 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 158 square metres for detached houses to 61 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 23% in their most recent assessment. In contrast, 19% 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
A02
B112
B225
B3514
C1818
C21016
C31213
D11411
D2138
E194
E273
F82
G112
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
1978-1999074135125
2000-2004011612162
2005-200913651931
2010-201434567100
2015-20219720000
Table 1 Domestic BER Certificates (2009-2021) 1
number
Period2009201020112012201320142015201620172018201920202021Total
January4,1084,6858,5716,5306,9737,0096,5265,2615,6875,1755,5225,8823,88775,816
February6,3315,6419,0326,3128,5297,5457,6636,8676,8146,4996,8857,6194,96190,698
March8,7686,1638,9496,5178,2088,3867,2677,5437,6306,5177,2157,1705,99696,329
April8,0595,4827,7804,4448,2988,7367,5917,3977,1397,0527,2451,995 81,218
May7,9335,4768,8785,8818,6478,7297,7167,9538,1768,3948,3322,449 88,564
June8,7355,8017,4654,8627,2658,2158,0027,4487,6897,5927,5705,794 86,438
July8,7785,9457,2615,5367,1029,3977,6756,5607,1247,5108,3517,606 88,845
August7,2656,4287,5325,0466,9748,1667,6477,0317,2537,1558,2286,891 85,616
September7,5097,4248,8484,9678,2779,9218,3577,6687,9727,2278,4088,775 95,353
October6,5828,3989,5646,6878,97510,7699,2227,9298,0578,31410,8108,400 103,707
November6,95911,5969,6108,7989,59910,8928,4019,0128,3958,2646,1808,070 105,776
December6,3288,0089,4686,3626,9337,7747,3096,0775,6795,7406,2606,475 82,413
               
Total87,35581,047102,95871,94295,780105,53993,37686,74687,61585,43991,00677,12614,8441,080,773
1 Includes all Certificates for Dwellings
Table 2 BERs by Period of Construction (2009-2021)
% of row 
Period of ConstructionEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
1700-18990012335710910143724,001
1900-19291012345710910143652,342
1930-19491013567912910132444,814
1950-1966112356811141110121669,725
1967-19771014691115161199888,819
1978-19820014913151817964357,442
1983-199300151013161917854296,275
1994-1999011611161919136431105,097
2000-200400291822201373210165,682
2005-200913112224179642110154,531
2010-20143428171042111000011,598
2015-20219711000000000063,836
               
Total813812131212106557934,162
Table 3 BERs by Type of Dwelling (2009-2021)
% of row 
Dwelling TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Apartment151214117910966573,653
Ground-floor apartment61371011111213865751,650
Mid-floor apartment1041012121211107432363,231
Top-floor apartment51481091012138551053,072
Basement Dwelling603274786109928299
Maisonette827111311101010533710,246
House12491214141211544834,709
Detached house6138111212121065510256,736
Semi-detached house1012612151413106444255,012
End of terrace house111251112121110656871,213
Mid-terrace house713913121111107557134,341
               
Total813812131212106557934,162
Table 4 BERs by County (2009-2021)
% of row  
CountyEnergy Rating Average age
AB1B2B3C1C2C3D1D2E1E2FGTotal
Carlow51271215131310545712,50930
Dublin 01-24914810111112117656210,25437
Dublin County17248111211119543370,23126
Kildare16138121313129433440,52823
Kilkenny51371213121211645814,99035
Laois4139121513118555814,18330
Longford1227121312141065697,82129
Louth9239161411108534626,84031
Meath1713915151197333434,88523
Offaly312510131210108781112,24834
Westmeath21371013151310655916,81932
Wexford51251013141412755730,32029
Wicklow121371112111110655727,43232
Clare31261013141412765823,56133
Cork City32491212111211766722,49145
Cork County72411151311109544784,25933
Kerry42371112131311755829,70030
Limerick City31271314141311645616,44937
Limerick County41261113141312654724,46732
Tipperary212610121213127671129,94540
Waterford City61261314141511644510,49136
Waterford County62371212131412645614,28135
Galway City51261013151612755414,38225
Galway County41371114141210655836,62629
Leitrim11271214121110667127,00833
Mayo41259131513126561024,78533
Roscommon21151114151197561211,12833
Sligo31271013131312766914,43232
Cavan2139151512119545913,76129
Donegal31261315141210655828,49330
Monaghan6238121111131165588,84335
                
Total813812131212106557934,16232
Table 5 BERs by Dublin Postal District (2009-2021)
% of row  
Dublin Postal DistrictEnergy Rating Average age
AB1B2B3C1C2C3D1D2E1E2FGTotal
Dublin 1525791111121385578,42432
Dublin 2925791112131075564,92934
Dublin 341368891012989138,57257
Dublin 44148910111313867710,75245
Dublin 5412581011141398868,84044
Dublin 651356781113989158,81960
Dublin 6W101268810121287885,05948
Dublin 720237109121299101511,74059
Dublin 8425889912128771014,54747
Dublin 91103781091112878711,22544
Dublin 104025131512121076764,02246
Dublin 1172612131111109655411,66331
Dublin 1241257910121399101010,51854
Dublin 132015101010910954437,94026
Dublin 1410358999111286659,91137
Dublin 15161410141512128321122,32417
Dublin 1612148111312131154329,22328
Dublin 175161015191412842214,31426
Dublin 1814610141512986221110,71118
Dublin 208369889121397542,34432
Dublin 227014101415161584327,70127
Dublin 24131261114131312643116,67622
                
Total914810111112117656210,25437
Table 6 BERs by Main Space Heating Fuel (2009-2021)
% of row  
Fuel TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Mains Gas825111615121184332366,681
Bulk LPG2261721181385221112,744
Bottled LPG0139131412111255591,051
Heating Oil112712151514126555338,664
Electricity22212358111386613157,431
Coal00011411141419363,249
Smokeless Fuel000001412141316396,312
Peat0011310121217421,446
Wood Pellets & Chips2410191416137632321,512
Wood Logs422333410129101028618
Solid Multi-Fuel00000127131313153631,010
               
Total713812131212106557920,718
– 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 Gas825111615121184332364,778
Bulk LPG2261721181386221112,700
Bottled LPG0139141512101165481,158
Heating Oil112712151514126555335,924
Electricity21212357111286615164,845
Coal0001122512141519283,123
Smokeless Fuel00011514161518305,464
Peat0012411131317401,473
Wood Pellets & Chips3411201415137632321,495
Wood Logs322333511131091025565
Solid Multi-Fuel00000127141414163129,193
               
Total713812131212106557920,718
– 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
Carlow3545145112,500
Dublin 01-247252210202,279
Dublin County7511141067,865
Kildare4733173140,406
Kilkenny2949128214,928
Laois3344913114,154
Longford164191237,753
Louth573282126,544
Meath4836133134,860
Offaly11551221112,128
Westmeath14541712316,767
Wexford1691810330,191
Wicklow4237164127,113
Clare13581710323,516
Cork City729172022,341
Cork County3939174283,842
Kerry1622210529,523
Limerick City5819203016,311
Limerick County2649168124,389
Tipperary14631210129,861
Waterford City6014233010,464
Waterford County2053196214,220
Galway City2039345214,276
Galway County765187336,518
Leitrim167171157,005
Mayo371158324,725
Roscommon470139311,124
Sligo163228614,395
Cavan967127513,679
Donegal079106428,237
Monaghan107111638,804
 
Total40371751920,718
Table 9 Main Space Heating Fuel by Period of Construction (2009-2021)
% of row  
Period of ConstructionFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
1700-18992938239123,455
1900-192929392110151,611
1930-1949443899144,692
1950-1966473976169,452
1967-1977394956188,162
1978-1982365247157,192
1983-19933445127295,776
1994-199934382341104,448
2000-200441351932164,761
2005-200946311824150,749
2010-20145328161210,853
2015-2021454510059,567
       
Total40371751920,718
Table 10 Main Space Heating Fuel by Type of Dwelling (2009-2021)
% of row 
Dwelling TypeFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
Apartment49544113,437
Ground-floor apartment476441248,986
Mid-floor apartment390590156,843
Top-floor apartment412541250,340
Basement Dwelling25116023266
Maisonette536371210,090
House177155334,690
Detached house1568962256,530
Semi-detached house4936961254,625
End of terrace house6022126170,984
Mid-terrace house61211161133,927
       
Total40371751920,718
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
1700-18996853455650104148158148116106119
1900-19296349445341891201251229891101
1930-1949516145524774111121112858299
1950-19667163555765671161271158886105
1967-19776864605580651321401108685110
1978-1982656664569170138143988583111
1983-1993595955585771147150978381110
1994-19996663586868771541631028584112
2000-20047471697770881681781059792116
2005-200982727179879317219310710198113
2010-20148678717586100195218122117109146
2015-202180818288100109187196123118112127
 
All7667677161881481581089490112
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
1700-1899434412380470397466419403370405359393
1900-1929489420410483395455413412374406364398
1930-1949363346274411458432373389332347314351
1950-1966426316262376397315335347298323292317
1967-1977379307252349339303289292277276250281
1978-1982330278237287290301244247249242219244
1983-1993345294245289337272227228236241218233
1994-1999281268231269246244205203219240219216
2000-2004256232199231235202188187204207186198
2005-2009167186162189178161151157172169154165
2010-201420911396120132951009984898596
2015-20211035847566752575352524952
             
All221233181242288211232230217233234226
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
1700-189910293821058310810810489968497
1900-192911694891078510710710790968498
1930-19498579588999999610078807285
1950-19661017055808768858767726574
1967-1977916852757968737263645767
1978-1982796250627271616159565059
1983-1993836653648260565655554956
1994-1999655850585553504950544950
2000-2004584942485042464547454045
2005-2009353833393533363740373337
2010-2014472319243019232318181721
2015-20212011911131012111010910
 
All495038516245585750535353
Table 14 Dwellings with Multiple BERs (2009-2021)
                 % of total
Earliest YearLatest YearTotal
A1A2A3B1B2B3C1C2C3D1D2E1E2FG
A1000
A20000000
A300000000000
B100000000001
B200001100000002
B3000012100000005
C10000133100000008
C200000233100000010
C300000233210000012
D100000123321000014
D200000122232100013
E10000011112210009
E20000011111111007
F0000011111111108
G00000111111111111
 
Total00225141816131184322100
– 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
Apartment826911111011106547166,668
Detached house4137101212121165611685,909
Semi-detached house712510131414127555442,022
Terraced house612610111112118779259,834
               
Total6137101212121165681,554,433

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 934,162 unique domestic BERs (one per dwelling) completed in the period 2009 to the end of March 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 March 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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