How green are the homes in your county? Only one in 20 houses has top energy rating

Workers install solar panels on a roof. Areas with newer builds have a higher proportion of A-rated homes. Photograph: courtesy of Construct Ireland

Just one in 20 Irish homes have a top energy rating, with tens of thousands of households paying significantly higher heating bills due to poor insulation and heating systems.

Building Energy Ratings (BER) have been carried out on 853,570 dwellings since 2009, some 51 per cent of the total number of households recorded in the 2011 census, analysis of Central Statistics Office figures show.

Dublin has the highest proportion of A-rated homes while Leitrim has the lowest proportion, with just 24 homes recorded as having an A rating amongst the audits performed from January 2009 to last September.

Leitrim, along with Roscommon, also has the highest proportion of G-rated homes in the country at 12 per cent, the worst rating on the home energy scale, indicating very poor insulation and single or poor double-glazed windows. If you are viewing this on The Irish Times app, please click here to view our interactive charts.

A BER certificate indicates a building’s energy performance and is similar to the energy label for household appliances such as fridges and TVs. It is based on a number of elements such as the dwelling’s construction type and insulation, ventilation and airtightness, heating system type, the wall, roof and floor dimensions, window and door sizes and the lighting type. A-rated homes typically have very well insulated attics and walls, and airtight construction, with mechanical ventilation and high-performance double- or triple-glazed windows. Typically, the insulation of the house and the performance of its windows decrease with each letter.

Single-glazed

Homes built in the 1980s and before typically rate from D to G, with G indicating a very badly insulated attic, little or no insulation in the attic and walls, and poor double-glazed or single-glazed windows.

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Since 2009, a BER certificate and advisory report is compulsory for all homes being sold or put up for rent, for all new dwellings, and to avail of energy efficiency improvement grants under the Better Energy Homes scheme. Protected structures are exempt from BER assessments.

One-fifth of all assessments have been carried out in apartments, with the rest being houses. Leinster is the province with the highest proportion of A-rated homes, with Dublin (21 per cent), Meath (13 per cent), Kildare (12 per cent) and Wicklow (9 per cent) the counties with the highest proportion of efficient homes. Connacht has the highest proportion of G rated homes with three counties, Leitrim (12 per cent), Roscommon (12 per cent) and Mayo (10 per cent) in the top five counties with the poorest rating.

Just 11 per cent of BER-assessed homes have a B rating. The majority (37 per cent) of assessed homes are C-rated. These were typically built in the early 2000s, have moderately insulated attic and walls and double-glazing, with average heating bills of €1,300 per year for a 100sq m, three-bed semi-detached home, compared to €380 for an A-rated home of the same size.

Almost all homes (97 per cent) built since 2015 are A-rated, with just 3 per cent B-rated. This compares to just 36 per cent of homes built from 2010-2014, a period when the majority of homes (55 per cent) were built to a B standard. 

The average age of all BER rated homes is 32 years. Cork city has the oldest average home age in the country at 45 years, while Meath and Kildare have some of the newest BER-assessed homes, an average age of 23 years. 

How Ireland heats its homes 

Gas and oil are the main fuels used to heat homes in Ireland, at 40 per cent and 38 per cent respectively.  Donegal is the county most reliant on oil, with 80 per cent of BER-assessed homes using the fossil fuel for heating. Like other counties including Sligo, Leitrim, Kerry and many parts of rural Ireland, it is not connected to the gas pipeline. Electricity accounts for 16 per cent of fuel types used to heat homes in Ireland, with solid fuel accounting for 5 per cent and liquefied petroleum gas (LPG) accounting for just 2 per cent of fuel used. 

Galway city has the highest reliance on electricity as a home heating source

BER-assessed homes in Offaly have the highest reliance on solid fuel, with almost one in four homes (23 per cent) relying primarily on materials such as turf for heating. Offaly is one of the primary counties for peat harvesting, but its high reliance on solid fuel is in stark contrast to Kildare, another major peat producer, where just 3 per cent of BER-assessed houses use solid fuel. However, many parts of Kildare are connected to the gas network. 

Galway city has the highest reliance on electricity as a home heating source, with a third of BER-assessed homes in the city using it compared to oil (40 per cent) and gas (20 per cent). In all of Ireland’s cities, electricity is the second-highest heating source used. 

Dublin 1-24 

Just 6 per cent of homes in Dublin 1-24 are A-rated. Dublin 6 and Dublin 7 are the areas of the city with the highest proportion of energy inefficient homes, with 16 per cent of assessed homes rated as G. Almost half (44 per cent) of homes in Dublin 7 have an energy rating of E to G. These are the areas with the oldest homes (an average age of 58 years). 

Areas with newer builds have a higher proportion of A-rated homes. Dublin 13, with an average dwelling age of 27 years, has the highest proportion of A-rated homes (16 per cent), followed by Dublin 15 which has the newest homes (17 years) with 14 per cent of homes rating A. The most efficient areas are typically those further out from the city centre (Dublin 13, 15, 16 and 18) with Dublin 2 being the exception, where 9 per cent of BER-assessed homes are A-rated. 
Ireland in Numbers is an Irish Times initiative to explore the stories behind the data. The data used has been provided by the Central Statistics Office.