The postcode Dublin 18 has the highest proportion of homes with an A energy rating in the country, as a third of dwellings there have reached the top rating, and homes are on average only 15 years old.
Figures released by the Central Statistics Office (CSO) on Monday detailed Domestic Building Energy Ratings (Ber) for the second quarter of 2023.
The release highlighted that a third of homes in Dublin 18 received the top A energy rating, the highest proportion of anywhere in the country.
Within Dublin, areas with the lowest proportion of A-rated homes included Dublin 3, Dublin 5 and Dublin 8, where only 5 per cent of dwellings received the top rating.
In cities and counties across the country, Kildare had the highest proportion of A ratings at 24 per cent, while Leitrim had the lowest proportion of A ratings, at just 3 per cent.
Dublin 18 also had the lowest average dwelling age, at 15 years for buildings with a Ber audit, while Dublin 6 had the oldest average, at 61 years.
Nationally, Kildare had the newest dwellings, with an average age of 22 years, while Cork city has the oldest homes with an average age of 46 years.
The CSO noted a “substantial increase” in the use of electricity as the main space heating fuel in newer homes, used in 88 per cent of homes constructed between 2020 and June 2023, compared with only 49 per cent of buildings constructed between 2015 and 2019.
So-called A ratings were given to 99 per cent of dwellings built between 2020 and 2023, and 96 per cent of those built between 2015 and 2019.
This compares with A ratings for just 34 per cent of dwellings built between 2010 and 2014, and 2 per cent of properties constructed between 2005 and 2009.
The CSO also released figures on Non-Domestic Building Energy Ratings for the second quarter of 2023, which show that schools and colleges are the most energy efficient buildings, with 40 per cent audited between 2009 and 2023 awarded an A rating.
More than a third (35 per cent) of non-domestic buildings constructed between 2020 and 2023 received an A rating, although overall only 3 per cent of non-domestic buildings audited since 2009 received an A rating.
There were 37,001 domestic Ber audits reported last quarter, while 1,191 non-domestic Ber audits were reported.
Domestic Ber audits were up 30 per cent in April and May compared with the same months in 2022, while in June the number of audits increased by 11 per cent.
Meanwhile for non-domestic buildings, the number of audits was down 3 per cent in April compared with the same month in 2022, but increased by 14 per cent in May and was up by 18 per cent in June.