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For more information on this release:
E-mail: environment@cso.ie Dympna Corry (+353) 1 4984207 Berna Lawlor (+353) 1 4984210
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 4 2018

Table A: BER Ratings by Period of Construction
% of row
Period of constructionEnergy rating 
ABCDEF-GTotal
1700-19770418252033245,143
1978-1999054036136233,323
2000-200409602262145,725
2005-2009135511031138,375
2010-20143655710010,793
2015-2018973000029,214

97% of Dwellings built in 2015-2018 were given an "A" rating

Figure 1: BER Ratings by Period of Construction
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Dwellings built in 2015-2018 were considerably more energy efficient than in earlier periods with 97% given an “A” rating compared with 36% in 2010-2014 and 1% in 2005-2009 (see Table A and Figure 1).

There was a decrease of 2.5% in the number of dwellings receiving a BER audit in 2018 compared with 2017 (see Table 1).

Dublin County had the highest combined “A” and “B” rating at 27% (see Table 4). Roscommon had the lowest proportion of combined “A” and “B” rating at 7%.

Dublin 18, with an average dwelling age of 17 years, had the highest proportion of combined “A” and “B” rating at 41% (see Table 5). The average age of dwellings in Dublin 15 that have had a BER audit done was also 17 years, but the combined "A" and "B" rating was much lower at 28% than in Dublin 18. The highest proportion of combined “F” and “G” rating was 27% for Dublin 7.

Mains gas was the main space heating fuel used in 57% of the 27,304 dwellings completed during 2015-2018 and with a Building Energy Rating (BER) audit. This was a substantial increase from 2000-2004 when 40% of dwellings with a BER audit used mains gas. There were contrasting trends for heating oil and electricity with 36% of 2000-2004 built dwellings using heating oil compared with 6% for dwellings built in 2015-2018. In contrast usage of electricity increased from 19% in 2000-2004 to 37% in 2015-2018 (see Table 9).

The average floor area of all dwellings with a BER audit was 111 square metres (see Table 11). This average size varied from 156 square metres for detached houses to 58 square metres for basement dwellings.

Table 14 examines dwellings that have had more than one BER audit carried out. In their earliest assessment only 5% of dwellings received either an “A” or “B” rating compared with 19% in their most recent assessment. In contrast, 21% of dwellings were rated “F” or "G" in their first BER assessment compared with only 5% in their latest BER assessment (see Table 14 and Figure 2).

Earliest BERLatest BER
A01
B101
B214
B3413
C1718
C21016
C31213
D11412
D2139
E1105
E283
F93
G122
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 rating. The data were weighted up to national level using Census of Population 2011 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, 9% of dwellings would have received a rating of "G" compared with 7% of dwellings in the actual BER data. In contrast, 2% of dwellings would have received an "A" rating at the national level, whereas 4% of dwellings that have had a BER assessment were given an "A" rating. 

All DwellingsDwellings with BERs
A24
B111
B223
B367
C11011
C21213
C31313
D11313
D21211
E176
E265
F65
G97
National DataBER database
A23
B111
B223
B367
C11011
C21213
C31313
D11313
D21211
E177
E265
F65
G97

1Dwellings with BERs have been weighted using Census of Population 2011 data to estimate a BER profile for All Dwellings at National level (see Background Notes). 

Table 1 Domestic Building Energy Ratings Certificates (2009-2018) 1
number
Period2009201020112012201320142015201620172018Total
January4,1024,6768,5666,5296,9687,0066,5235,2575,6855,16760,479
February6,3225,6249,0266,3108,5277,5417,6606,8656,8116,49171,177
March8,7696,1588,9446,5148,2098,3857,2637,5387,6276,51375,920
April8,0425,4837,7784,4428,2998,7347,5907,3937,1357,05171,947
May7,9255,4758,8785,8748,6448,7287,7167,9548,1798,39077,763
June8,7335,7797,4654,8627,2638,2188,0017,4467,6887,59073,045
July8,7755,9647,2575,5357,0989,3967,6756,5607,1227,51072,892
August7,2696,4317,5325,0446,9748,1657,6487,0277,2517,15570,496
September7,5197,4298,8524,9738,2819,9208,3577,6727,9717,22778,201
October6,5928,4049,5676,6928,97910,7719,2207,9328,0658,32084,542
November6,96711,6119,6188,8039,60110,8978,4129,0238,3978,28191,610
December6,3408,0139,4756,3646,9377,7787,3116,0795,6845,74469,725
            
Total87,35581,047102,95871,94295,780105,53993,37686,74687,61585,439897,797
1 Includes all Certificates for Dwellings
Table 2 BER Ratings by Period of Construction (2009-2018)
% of row 
Period of ConstructionEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
1700-18990012234710910143820,791
1900-19290012234710910143744,651
1930-194900134579121010132539,160
1950-1966001356811141111131761,190
1967-19770013691115171199879,351
1978-198200148131518181064352,340
1983-19930014913161918854386,989
1994-199900151015192014643193,994
2000-200400171722211484221145,725
2005-200913102124189642110138,375
2010-20143629161042111000010,793
2015-2018972100000000029,214
               
Total413711131313116557802,573
– No dwelling received this BER rating for this period of construction
Table 3 BER Ratings by Type of Dwelling (2009-2018)
% of row 
Dwelling TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Apartment14111312710101065564,267
Ground-floor apartment21371011101213976744,938
Mid-floor apartment451012121211118433353,881
Top-floor apartment2148109912149651046,323
Basement Dwelling1326568711101032236
Maisonette22712131110101254478,412
House12491214141311544836,749
Detached house3127111313131165510217,053
Semi-detached house611511151514116554214,978
End of terrace house61151013121211767859,713
Mid-terrace house412813131111117667116,023
               
Total413711131313116557802,573
– No dwelling received this BER rating for this dwelling type
Table 4 BER Ratings by County (2009-2018)
% of row  
CountyEnergy Rating Average age
AB1B2B3C1C2C3D1D2E1E2FGTotal
Carlow31261214141411655710,91829
Dublin 01-24524710111112127667178,76636
Dublin County132481113121210544458,71227
Kildare91271214141310543433,01923
Kilkenny21271213131312755912,99035
Laois1139111514129666912,34329
Longford1227121212151165696,81628
Louth4239161512119534622,28132
Meath10138151613118433527,75124
Offaly11249131211119891110,73934
Westmeath11271013151411666914,82931
Wexford21251014151512755826,44529
Wicklow61271112121211755822,74333
Clare1126913151412765821,37632
Cork City21481212111211866721,62745
Cork County31411151412109544770,86532
Kerry21371112131412755826,37529
Limerick City21151214151413755713,27936
Limerick County21261114151413655722,97132
Tipperary112510121313128671126,73140
Waterford City3126121314161374468,74435
Waterford County41261213131412645712,65835
Galway City3125913161713755412,22224
Galway County21271114141311755832,79128
Leitrim00261214131110667126,10131
Mayo21259131514126561021,53932
Roscommon10151115151210756129,69832
Sligo11271012121313866913,04631
Cavan1139151612129655912,05028
Donegal11261315141311655824,44529
Monaghan2238121112141275587,70335
                
Total413711131313116557802,57332
Table 5 BER Ratings by Dublin Postal District (2009-2018)
% of row  
Dublin Postal DistrictEnergy Rating Average age
AB1B2B3C1C2C3D1D2E1E2FGTotal
Dublin 1226791011131386587,29631
Dublin 2336781112131186574,16735
Dublin 3203688911129910137,41955
Dublin 4214791010131397779,38844
Dublin 53125810111513108867,60743
Dublin 641346781113989167,79058
Dublin 6W512688101212989104,20350
Dublin 71013699121399111610,29957
Dublin 81258881012138781112,46445
Dublin 950368109111398999,25345
Dublin 101025131513121187773,36045
Dublin 115171212111111965549,97530
Dublin 12212468101213101011118,77853
Dublin 13141410101110111065436,29427
Dublin 1463578910111287768,48837
Dublin 15122410141513139422118,55817
Dublin 168148111312141264427,78527
Dublin 17516914191413842214,04825
Dublin 18871115151298732219,12517
Dublin 208379888121396542,09630
Dublin 22201491415181795336,36727
Dublin 2471251215141512754214,00622
                
Total524710111112127667178,76636
Table 6 BER Ratings by Main Space Heating Fuel (2009-2018)
% of row  
Fuel TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Mains Gas624101515131295332314,747
Bulk LPG2261721181396322111,418
Bottled LPG113813151212125459957
Heating Oil112612151615126555302,526
Electricity101123681315108716120,662
Coal00011411141519353,392
Smokeless Fuel00001412151417375,641
Peat0012310121217421,473
Wood Pellets & Chips3611191315117532321,350
Wood Logs42232349139101030600
Solid Multi-Fuel00000127131414163429,273
               
Total413711131313116557792,039
– No dwelling received this BER rating for this main space heating fuel type
Table 7 BER Ratings by Main Water Heating Fuel (2009-2018)
             % of row 
Fuel TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Mains Gas624101515131295332312,984
Bulk LPG2261721181396321111,372
Bottled LPG0039141512111264591,052
Heating Oil112712151615126555300,121
Electricity91123681215108718126,948
Coal0001112513151619273,278
Smokeless Fuel0011514161519295,008
Peat0012411131217391,498
Wood Pellets & Chips3611201315117532321,342
Wood Logs3213335111310101126556
Solid Multi-Fuel00000127141414173027,880
               
Total413711131313116557792,039
– No dwelling received this BER rating for this main water heating fuel type
Table 8 Main Space Heating Fuel by County (2009-2018)
% of row    
CountyFuel Type 
Mains GasHeating OilElectricitySolid FuelLPGTotal
Carlow3546116210,910
Dublin 01-247362110172,877
Dublin County7612111056,704
Kildare4836123132,903
Kilkenny2951108212,933
Laois3245815112,316
Longford262201336,751
Louth563462122,025
Meath4739103127,728
Offaly10551023110,619
Westmeath14541513314,774
Wexford1701511326,337
Wicklow4340115122,628
Clare13581511321,332
Cork City729162021,480
Cork County3941144270,492
Kerry1642010526,229
Limerick City5620214013,146
Limerick County2849148122,900
Tipperary14641011126,647
Waterford City621421308,721
Waterford County2153176212,600
Galway City2040325212,126
Galway County767177332,693
Leitrim166161166,098
Mayo372148321,497
Roscommon471121039,697
Sligo163219513,024
Cavan968118511,968
Donegal08196424,215
Monaghan9739737,669
 
Total40381552792,039
Table 9 Main Space Heating Fuel by Period of Construction (2009-2018)
% of row  
Period of ConstructionFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
1700-18992938229120,314
1900-192930392010144,018
1930-1949433899139,058
1950-1966474076161,013
1967-1977385056178,730
1978-1982365248152,101
1983-19933446117286,509
1994-19993338235193,412
2000-200440361942144,905
2005-200946301824134,618
2010-20145526151210,057
2015-2018576370127,304
       
Total40381552792,039
Table 10 Main Space Heating Fuel by Type of Dwelling (2009-2018)
% of row 
Dwelling TypeFuel TypeTotal
Mains GasHeating OilElectricitySolid FuelLPG
Apartment46447124,015
Ground-floor apartment477431242,772
Mid-floor apartment401580149,253
Top-floor apartment413541244,077
Basement Dwelling27106021210
Maisonette53736128,296
House187055336,729
Detached house1570662216,886
Semi-detached house4938671214,660
End of terrace house602396159,509
Mid-terrace house61221061115,632
       
Total40381552792,039
Table 11 Average Floor Area by Period of Construction and Type of Dwelling (2009-2018)
m2
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-18996853455652105149158148116106119
1900-19296450435442891191241219790100
1930-1949516245515074111120110858298
1950-19667063545658671171251148886104
1967-197767656056101651321391098584110
1978-19826266645510069138142978482110
1983-1993585955585771147149968281109
1994-19996663586758771531611018483111
2000-20047471697769881661771049692115
2005-200981727179909417119110610198111
2010-2014847871768699195214122117109142
2015-20188081838781112187196126123117132
 
All7667667158861481561069289111
Table 12 Average Primary Energy Use by Period of Construction and Type of Dwelling (2009-2018)
kWh/m2/year
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-1899434420384482412472417409378416364399
1900-1929479428429495394454412420383415373406
1930-1949363349281423458441374398342362324360
1950-1966415326289384515317336353305334298324
1967-1977384310255355319313289298282281254286
1978-1982336283239290309304244251253245222248
1983-1993346298252296337276228233241244222238
1994-1999283273236276278250206207226246224221
2000-2004253237204237260208189191210215192203
2005-2009170187161190179163151161175171156167
2010-201420511194118132931009883888494
2015-20181036150586363575655555155
             
All221244193252327228232239230249245236
Table 13 Average Carbon Dioxide Emissions by Period of Construction and Type of Dwelling (2009-2018)
kgCO/m2/year
PeriodApartmentGround-floor apartmentMid-floor apartmentTop-floor apartmentBasement DwellingMaisonetteHouseDetached houseSemi-detached house End of terrace houseMid-terrace houseAll dwelling types
1700-1899102958310887110107105911008598
1900-1929114979411086107107109929987100
1930-1949858060931011009610281847587
1950-19669972618211368858969756776
1967-1977926953767771737465655968
1978-1982816450637771616360565160
1983-1993836755668262565856565157
1994-1999666152616355505052565052
2000-2004585144515644464649474247
2005-2009363934403533363841373438
2010-2014462318233019232317181721
2015-201820129111212121211101011
 
All505341547149585953575656
Table 14 Dwellings with Multiple BER Ratings (2009-2018)
                 % of total
Earliest YearLatest YearTotal
A1A2A3B1B2B3C1C2C3D1D2E1E2FG
A1000
A200000
A30000000
B100000000000
B20000000000001
B3000012100000004
C10000023100000007
C20000232100000010
C300000133210000012
D100000123321000014
D200000122232100013
E100000111122100010
E20000011111111008
F000011111111109
G00000111111111212
                 
Total00114131816131295332100
– No dwelling received this BER rating combination for the earliest and latest assessments
Table 15 BER Ratings Weighted to National Level (2009-2018)
             % of row  
Dwelling TypeEnergy Rating Total
AB1B2B3C1C2C3D1D2E1E2FG
Apartment326911111011117558164,498
Detached house2127101213121165611675,791
Semi-detached house311510141515127665434,414
Terraced house2116101212121287710262,642
               
Total2126101213131276691,537,345

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 802,573 unique domestic BERs (one per dwelling) completed in the period 2009 to the end of December 2018. 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 2009-2018 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 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 December 2018; 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 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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