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Energy rating of housing in Northern Ireland
Up to March 2023

An Official Statistics in development publication
Published by: Analytics Division, Department for Communities

Contact: Analytics Division
Email:
Tel: 028 9082 3400
Coverage: Northern Ireland
Frequency: Annual
Publication Date: 10 July 2024

Main points

  • Dwellings in Northern Ireland with a valid Energy Performance Certificate (EPC) had a median energy rating in band D, with a score of 65.

  • Flats and maisonettes were the property type in Northern Ireland with the highest median energy rating with a score of 74, equivalent to band C.

  • Social dwellings had a median energy rating certified at band D in most of the local government districts, apart from Belfast and Antrim and Newtownabbey which had median energy ratings certified at band C.

  • In Northern Ireland, approximately four in ten (39%) dwellings with a valid EPC had an energy rating band at C or above.

  • Of all dwellings built before 1930 in Northern Ireland, approximately 90% were rated in bands D to G.

  • Over nine in ten dwellings used either gas or oil as a main fuel source for heating in each local government district.

Section 1: Energy rating in Northern Ireland

Several factors affect the energy rating of a dwelling, including property type and when or how it was constructed. This bulletin highlights the types of dwellings typically associated with high and low energy rating scores.

Energy Performance Certificates (EPCs) indicate the energy rating (based on running costs) and environmental impact of dwellings along with improvement recommendations, if applicable. They are based on data about a building’s energy features, for example, levels of insulation, efficiency of heating systems and the inclusion of renewable energy generation technologies, as well as standardised assumptions for occupancy and behaviour. They are collected by an accredited energy assessor and entered into government-approved software to generate an EPC score, typically ranging from 1 to 100. Domestic EPCs are rated from A to G, where A is likely to result in lower energy bills.

The scores associated with each energy rating band are:

  • band A - 92 plus (most efficient in terms of running cost)
  • band B - 81 to 91
  • band C - 69 to 80
  • band D - 55 to 68
  • band E - 39 to 54
  • band F - 21 to 38
  • band G - 1 to 20 (least efficient in terms of running cost)

This analysis uses EPC data to present energy rating, the main fuel type used in heating, and the carbon dioxide (CO2) emissions of dwellings with an EPC for Northern Ireland. It is based on one record per dwelling, using records from April 2013 to March 2023. This is because EPC’s are only valid for 10 years from when dwellings are constructed, converted, sold or let.

More information on the base population can be found in Data sources and quality.

Energy rating by region

The median energy rating score for Northern Ireland was 65 for all records in the ten year period to March 2023, which is equivalent to band D. Analysis by local government district shows that although there is some variation in the average energy rating score, the average score for each LGD falls into band D. Causeway Coast and Glens had the lowest median score (61), while Belfast had the highest median score of 68.

Figure 1: Median energy rating score, by Local Government District, April 2013-March 2023

Energy rating by property type and tenure

Energy rating varies by property type. Overall, flats and maisonettes were the property type in Northern Ireland with the highest median energy rating, with a score of 74, which is equivalent to band C (see Figure 2). Flats and maisonettes are the only property type that had a score above band D.

Detached dwellings had the lowest median energy rating score of property types in Northern Ireland (60). This may be a result of external wall exposure being higher in houses, compared with flats and maisonettes which are more likely to be grouped in blocks. While there was a larger difference in energy rating between flats and houses, there was a smaller difference between the different types of houses.

Figure 2a: Median energy rating score by property type, Northern Ireland, April 2013 - March 2023

Looking at dwellings solely by tenure, social rented dwellings in Northern Ireland had the highest median energy rating score, 68, equivalent to a very high band D. Owner-occupied dwellings scored the lowest, with a score of 58, equivalent to a low band D. However, this does not account for property type.

Figure 2b: Median energy rating score by tenure, Northern Ireland, April 2013 - March 2023

By combining property type and tenure, a more detailed picture of the energy rating of housing appears. Social rented dwellings score the highest median energy rating scores across all property types, with the highest median score being 74 for social rented flats and maisonettes. (Figure 3).

Figure 3: Median energy rating score by tenure and property type, Northern Ireland, April 2012 - March 2023

Energy rating by property age

The age of a dwelling tends to affect the energy rating, as building techniques and regulations have changed over time, in addition to the effects of ordinary use and aging. Dwellings constructed after 2014 had a median energy rating score equivalent to band B, 83 in Northern Ireland (Figure 4). In contrast, dwellings constructed before 1930 had a median score of 51, which is equivalent to band E.

Figure 4: Median energy rating score, by property age, Northern Ireland, April 2013 - March 2023

Energy rating for new and existing dwellings

As at March 2023, there were approximately 319,000 unique valid entries on the EPC register. The properties covered by the EPC register are a mix of newly built or converted dwellings and existing properties being issued with a first or updated EPC. New and existing dwellings are assessed using slightly different methodologies (the standard assessment procedure and the reduced standard assessment procedure).

The median energy rating score for new and existing buildings can differ because of the use of modern techniques and materials in the building of newer properties. The median energy rating score for new dwellings in Northern Ireland was equivalent to band B (83), compared with the score for existing dwellings that was equivalent to band D (62).

The median energy rating score for new properties in Northern Ireland were similar across all housing types, ranging from 82 to 83 (Figure 5). However, as existing dwellings make up the majority of the EPC records analysed in Northern Ireland (83%), the energy rating patterns shown in the existing dwellings have a greater impact on the overall figures for all dwellings.

Figure 5: Median energy rating score for new and existing dwellings, by property type, Northern Ireland, April 2013 - March 2023

Property type

Section 2: Individual EPC bands

When looking at all dwellings in Northern Ireland, approximately two-fifths (39%) of dwellings achieved an energy rating of C or above. However, the most common rating in Northern Ireland was a rating of D (35%).

Three-quarters (75%) of new dwellings achieved a band B and 23% achieved a band C rating. In contrast, only 1% of existing dwellings had a rating in band B. Most existing dwellings were in bands C and D; 26% in band C, and 42% in band D.

Looking at age of property for individual EPC bands, dwellings built before 1930 were most commonly rated in band D (33%) and E (30%) (Figure 8). In fact, 90% of all dwellings in Northern Ireland built before 1930 were rated in bands D to G. For dwellings constructed after 2014, band B was the most common rating, with 79% of such dwellings in Northern Ireland.

Figure 6: Individual EPC bands by age of property band, Northern Ireland, April 2013 - March 2023

Although the highest proportion of owner-occupied dwellings were rated in band D, a larger proportion of such dwellings achieved a band B than private rented properties in Northern Ireland. Social rented dwellings in most local government districts were most commonly rated in band D, with the exception of Belfast where the most common rating was band C and Antrim and Newtownabbey with an equal proportion of dwellings rated C and D.

Figure 7: Individual EPC bands by tenure, by local Government District, April 2013 - March 2023

Owner-occupied
Private rent
Social rent

Section 3: Heating fuel type for dwellings

One of the main contributors to energy use in the home is space and water heating, with different sources of heating seen as more or less energy efficient. As part of the Energy Performance Certificate (EPC) assessment, the main fuel type of heating is recorded. The analysis presented below focuses on the fuel type that directly powers a dwelling’s heating. This means that someone who is on a 100% renewable tariff for their electricity will be categorised as using electricity as their heating fuel type rather than renewable energy. If there was no heating record, for this analysis we group these dwellings in the “others/none” category.

As of March 2023, 53% of dwellings in Northern Ireland with an EPC used oil for their heating. Gas was the second most common fuel type for heating (42%). All other fuel types make up just 5% of fuel used in heating in dwellings in Northern Ireland.

Among local government districts, Belfast had the highest proportion of homes that used gas to fuel their heating (78%). In contrast, 89% of dwellings in Mid Ulster used oil to fuel their heating.

Figure 8: Main fuel type used in heating, by local government districts, April 2013 - March 2023

Section 4: Carbon dioxide emissions

Energy Performance Certificate (EPC) data on estimated carbon dioxide (CO2) emissions are based on standardised assumptions about how residents will use the dwelling (such as number of occupants, heating patterns and hot water usage).

Median estimated CO2 emissions per year for new and existing dwellings

Figure 9 shows that for April 2013-March 2023, in all local government districts apart from Fermanagh and Omagh, the median estimated CO2 emissions for existing dwellings were more than double the estimated emissions for new dwellings. In Fermanagh and Omagh, the median estimated CO2 emissions for existing dwellings were 1.9 times the estimated emissions of new dwellings.

Belfast had the lowest median estimated CO2 emissions for both new and existing dwellings with 1.4 and 3.2 respectively. Fermanagh and Omagh had the highest median CO2 emissions for new dwellings with 3.0 and Mid Ulster had the highest median CO2 emissions for existing dwellings with 5.8.

Figure 9: Median estimated CO2 emissions, for new and existing dwellings, by local government district, April 2013-March 2023

scatter chart showing co2 emissions

Section 5: Representativeness of dwellings covered by an EPC

To analyse the representativeness of dwellings covered by Energy Performance Certificates (EPCs), the EPC data was compared with the Housing Stock statistics published by Land and Property Services (LPS) in June of each year.

As of March 2023, around 39% of all residential dwellings in Northern Ireland had a valid EPC registered in the previous 10 year period. Across local government districts (LGDs) there was some variation in the proportion of housing stock with a valid EPC, with almost half (48%) of homes in Belfast having a valid EPC while in Fermanagh and Omagh the comparable figure was 29%.

Analysis by property type indicated that flats and maisonettes had the highest coverage (53%), while detached houses had the lowest coverage (27%).

Glossary

Dwelling

A dwelling is an address containing a unit of accommodation that can comprise one or more household spaces.

Energy efficiency

Energy efficiency relates to the concept of efficient energy use, which means using less energy to provide a given amount of heating or lighting. Using less energy reduces emissions of carbon dioxide, although there can be exceptions. For example, using bio fuels will reduce the carbon emissions but is likely to lead to higher running costs and therefore lower energy efficiencies.

Energy rating

The energy rating and score is a measure of the overall efficiency of a dwelling reflecting its modelled running cost/m2/annum. This score is based on the modelled performance of the building and its fixed services for heating, cooling, ventilation, lighting and any ancillary power needed to service these functions. It does not include other ancillary uses, such as general power for day-to-day appliances or cooking. The higher the score, the more cost-efficient the home. The score is produced during an Energy Performance Certificate (EPC) assessment and is based on standardised assumptions for occupancy and behaviour.

Energy Performance Certificate

Energy Performance Certificates (EPCs) are required for all buildings (domestic and non-domestic), when constructed, sold or rented. There are some exemptions, for example for buildings used as places of worship. EPCs are valid for 10 years. The EPC records how energy efficient a property is as a building. The EPC uses an A-to-G rating scale, where A is the most efficient and G is the least efficient.

Existing dwelling

Statistics for existing dwellings were created using data from the latest EPC record available for existing dwellings in the past 10 years. Existing dwellings are those that are required to undergo an energy performance assessment as they are either being sold or let and are not newly constructed or converted.

New dwelling

Statistics for new dwellings are generated using data from new dwelling EPC records. A new dwelling is any dwelling that has been newly constructed, created by conversion or has undergone a change of use and is now required to have an energy performance assessment.

Standard assessment procedure (SAP)/Reduced standard assessment procedure (RdSAP)

The SAP software for new dwellings is significantly more detailed than RdSAP and would be considered more robust. RdSAP EPCs are designed to be non invasive, and to be carried out on existing buildings where the exact make and model of every material that has gone into the build may not be available. Instead of using precisely calculated thermal performance data for each element, the RdSAP software makes an assumption based on the construction date of the property.

Data Sources and quality

Energy Performance Certificate data

This article contains analysis of the Energy Performance Certificate (EPC) data provided by the Department of Finance (DoF) for Northern Ireland.

This article uses analysis of the stock of dwellings with a valid EPC. This gives a good indication of the current situation across Northern Ireland.

An EPC is valid for 10 years, so the analysis presented in this bulletin is based on all valid EPC lodgements (the latest record for each dwelling) from April 2013 to March 2023.

All data was matched to the Pointer database using the Unique Property Reference Number (UPRN) to confirm the property still existed.

Only data where the building status indicated that it was built was used in the analysis. Any property under construction, demolished, etc. was excluded from analysis.

Duplicates were removed, by matching on UPRN, inspection date and lodgement date which left approximately 319,000 entries to analyse.

Interpreting these statistics

The analysis in this article does not cover all dwellings in Northern Ireland because not every dwelling has an EPC (as these are only required when a dwelling is constructed, converted, sold or let). EPCs are valid for 10 years, so do not necessarily reflect energy efficiency improvements. Dwellings can have more than one record, but only the latest record was included in the analysis, so dwellings are not double counted in any time period analysed.

Some dwellings included in the statistics may have changed tenure since the date of their latest EPC. For instance, dwellings that had an EPC for reasons other than being let may have since entered the private or social rented sector.

Official Statistics in development

Official statistics in development (previously called Experimental Statistics) are official statistics that are undergoing a development, and may be new or existing official statistics. They are published to involve users and stakeholders in their development and as a means to ensure they will meet user needs going forward. As these statistics are still in development, they are subject to retrospective revision in any future releases. The methodology and quality assurance are still in development and are subject to change.

These official statistics are produced in compliance with the Code of Practice for Statistics.

Feedback on these statistics is particularly welcome from users and will be used to further develop the statistics. You are able to give feedback on our user engagement survey.

Our statistical practice is regulated by the Office for Statistics Regulation (OSR). OSR sets the standards of trustworthiness, quality and value in the Code of Practice for Statistics that all producers of official statistics should adhere to. You are welcome to contact us directly with any comments about how we meet these standards by emailing analyticsdivision@communities-ni.gov.uk. Alternatively, you can contact OSR by emailing regulation@statistics.gov.uk or via the OSR website.