Background Notes and Methodology

Scope and Background

The New Dwelling Completions series is produced by the CSO on a quarterly basis. A Housing Analytics Group (HAG) was established in 2017 by the Department of Housing, Planning and Local Government (DHPLG). This group, which met for the first time in May 2017, consists of representatives of bodies with a significant interest and role in housing, housing policy and related policy areas. 

The HAG focused on a review of housing related data published nationally and in particular on the number of dwellings built every year. Arising from the work of this group and other direct discussions between the CSO and DHPLG, a significant outcome was to assess the suitability of current housing indicators for estimating the number of new dwelling completions in Ireland.

Historically, the number of new dwellings built in Ireland, as published by the DHPLG, was based on the number of connections to the ESB Network. However, in recent years it became apparent that this series was overestimating the levels of new dwelling construction in Ireland. The New Dwelling Completions series will look to replace this and other available indicators of housing activity in Ireland. This series will include information on dwelling type, urban/rural location, activity by Local Authority and by Eircode Routing Key (and now Local Electoral Area). It will continue to be based on domestic ESB connections but will correct for over-coverage by using additional information from ESB Networks and incorporating data from other sources. It also includes data on the number of reconnections and on houses from unfinished housing developments that are coming back into use. This will provide policy-makers with a valuable insight into the number of new dwellings available for occupation in the quarterly period concerned and also show data on the numbers of dwellings being constructed.

Geographic Split

The New Dwelling Completions data series is based on the number of new dwellings connected by the ESB Network to the electricity supply and may not accord precisely with geographical boundaries. The NDC series is split into local authorities, Eircode Routing Keys and Local Electoral Areas based on the information of the substation rather than the exact location of the dwelling. As Eircode becomes available as the unique identifier, it will replace the source of identifying the location of a new dwelling. 

The breakdown of ESB connections by type of connection and dwelling is based on NUTS3 regions as described below:

• Border: Cavan, Donegal, Leitrim, Monaghan, Sligo
• Dublin: all four local authorities within Dublin
• Mid-East: Kildare, Louth, Meath, Wicklow
• Midlands: Laois, Longford, Offaly, Westmeath
• Mid-West: Clare, Limerick, Tipperary
• South-East: Kilkenny, Waterford, Wexford
• South-West: Cork City and County, Kerry
• West: Galway City and County, Mayo, Roscommon

Classification

ESB connections are classified into four categories:

• New dwelling completion: Recently constructed dwelling, where a dwelling is a self-contained unit of living accommodation.
• Reconnection: A dwelling that has been reconnected to the ESB Network after a period of two years of disconnection.
• UFHD: Connection to the ESB Network of previously completed dwellings in Unfinished/Ghost estates. A methodology was developed to identify houses that were complete in 2011 and were subsequently connected to the ESB Network. Although these dwellings may have required finishing to become available for use they are not new dwelling completions for the purposes of this publication. However, dwellings in Unfinished/Ghost estates which were not in a complete state in 2011 are included as new dwelling completions on connection to the ESB Network.
• Non-dwelling: A building connected to the ESB Network through a domestic connection that is not constructed for residential use. 

The dwelling type is defined by the ESB Network and classified into three categories:

• Single: If a single domestic dwelling or farm premises is to be connected to the ESB Network, Form NC2 (through an online application system) must be completed and the dwelling is defined as 'single'.
• Scheme: If a new multi-unit development with two or more houses is to be connected to the ESB Network, Form NC1 (through an online application system) must be completed and each dwelling is defined as 'scheme'. 
• Apartment: If a new multi-unit development with two or more apartments is to be connected to the ESB Network, Form NC1 (through an online application system) must be completed and each dwelling is defined as 'apartment'.

The classification of urban and rural dwellings is also defined by the ESB Network and based on the Distribution Use of System (DUoS) tariff, which is a fee that ESB Networks charge Electricity Suppliers for use of the Electricity Distribution System¹. 

• Urban: DUoS Group = DG1, urban domestic.
• Rural: DUoS Group = DG2, rural domestic.

Coverage

Only domestic connections where a dwelling is a self-contained unit of living accommodation are included in the New Dwelling Completions series. Commercial properties, shared and communal living arrangements are excluded.

Revisions

The New Dwelling Completions series is a new statistical product compiled from third party data sources. The series will be revised on an ongoing basis as more timely and accurate data sources become available and these data sources can be matched to the ESB new connections data set. BER Assessment data is used to validate the status of New Dwelling Completions, reconnections, UFHDs and non-dwellings. This will result in regular revisions to previous quarters due to the time lag between ESB connections and BER assessment. Historical data within the current release and PxStat interactive tables are impacted by revisions but data within archived releases has not been revised.

Data sources

The primary data source used for the New Dwellings Completions series is the ESB domestic connections dataset where the date that the connection is energized determines the date of completion. It is accepted that the ESB domestic connections dataset overestimates new dwellings and the CSO has adjusted for this overcount by using additional information from the ESB and other data sources. The ESB domestic connections dataset is matched by the CSO to Building Energy Rating (BER) data, compiled by the Sustainable Energy Authority Ireland (SEAI). Under the Statutory Instrument (S.I.) No. 243 of 2012, all residential property for sale must disclose their BER assessment (with some very minor exceptions). The BER includes detailed information on the type of dwelling, the type of certificate (Provisional, Final, Existing) as well as the date of assessment and construction. As the collection, storage and maintenance of Eircode improve, other data sources can be further consulted to improve the accuracy of the series.

Average New Dwelling Size Index

The average new dwelling size index is based on measurements of the total floor area recorded by a BER Assessor in accordance with the BER Regulations, the BER Assessor's Code of Practice and all other directions issued by the SEAI². As an MPRN, the unique identifier for an ESB connection is required for the BER certification process it is possible to link new housing completions data to BER certificates to produce the index. The match rate between new dwelling completions and BER certificates is consistently highest among scheme dwellings. Table 7 shows the percentage of new dwelling completions that can be matched to a BER certificate by dwelling type and year. Between 2015 and 2020, approximately nine out of ten scheme dwellings had a BER certificate compared to about one in five single dwellings. The match rate for apartments has increased in recent years and stood at 79% in 2020.

Show Table 7: New dwelling completions and BER match rate, 2011 - Q2 2021 Hide Table 7: New dwelling completions and BER match rate, 2011 - Q2 2021

Table 7: New dwelling completions and BER match rate, 2011 - Q2 2021
Period	Single	Scheme	Apartment	Overall match rate
2011	16%	74%	46%	31%
2012	15%	79%	29%	29%
2013	17%	80%	47%	36%
2014	16%	87%	61%	46%
2015	22%	90%	28%	53%
2016	24%	90%	50%	61%
2017	24%	94%	69%	69%
2018	22%	94%	68%	72%
2019	24%	95%	77%	75%
2020	20%	94%	79%	73%
Q1-Q2 2021	5%	80%	39%	53%

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While the time lag between connection to the ESB network and BER assessment can explain missing BER certificates, the data in Table 7 indicates that there are additional factors at play for single dwellings and apartments.

The low match rate for single dwellings is due to the large number of self builds where dwellings are not intended for sale or rent, similarly, the low match rate for apartments can be explained by dwellings not intended for sale. These include conversions from single dwellings as well as social housing and developments in the build-to-rent sector. Such developments will often have a range of provisional BER certificates or a partial number of BERs for the development without having a final BER for all properties. 

¹ Rules for Application of DUoS Tariff Group: https://www.esbnetworks.ie/docs/default-source/publications/rules-for-application-of-duos-tariff-group.pdf?sfvrsn=a44b33f0_4

² BER Assessor Support: https://www.seai.ie/home-energy/building-energy-rating-ber/support-for-ber-assessors/domestic-ber-resources/

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