Houses with BER ratings F and G rated consumed 60 per cent more electricity per square metre than A and B rated dwellings in 2021, according to the latest figures released by the Central Statistics Office (CSO).
While for gas usage, F and G rated dwellings consumed 38 per cent more gas per square metre than A and B rated dwellings last year.
A and B rated dwellings used 42 kilowatt-hours of electricity per square metre in 2021 compared with 79 kWh per square metre for D and for E and 67 kWh per square metre for F and G rated dwellings.
The mean electricity consumption in 2021 for dwellings built in 2005-2021 was 48 kWh per square metre which was around two-thirds of the figure for dwellings built in 2000-2004 of 75 kWh per square metre.
Mean electricity consumption decreased in 2021 compared with 2020 for apartments and mid-terrace houses, but it increased for end-of-terrace houses, semi-detached houses and detached houses.
A detached house used 8,039 kWh of electricity in 2021 which was 70 per cent higher than the corresponding mean electricity consumption for a mid-terrace house.
More energy-efficient dwellings had more floor area. A and B rated detached houses had an average of 230 square metres compared with an average of 89 square metres for detached houses with an F or G rating.
Dympna Corry, Statistician in the Environment and Climate Division, said: "The Central Statistics Office (CSO) receives and publishes data on Metered Electricity Consumption and Domestic Building Energy Ratings. This is the first time the CSO has combined these two datasets. The release complements a CSO release that examines how metered gas consumption varied by type of dwelling. This analysis examined households that had a BER and used electricity as their main space heating fuel.
"Dwellings with better energy ratings used less electricity per square metre of dwelling floor area. Average electricity consumption per square metre in 2021 varied from: 42 kWh for A and B rated dwellings; 75 kWh for C rated dwellings; 79 kWh for D rated dwellings; 79 kWh for E rated dwellings; and 67 kWh per square metre for F or G rated dwellings. These figures are well below the average gas consumption per square metre reflecting that electricity is used less than gas as a main space heating fuel."
Gas
While F and G rated dwellings consumed 38 per cent more gas per square metre than A and B rated dwellings in 2021.
F and G rated dwellings used 120 kilowatt-hours of gas per square metre in 2021 which was 38 per cent higher than the 87 kWh used by A and B rated dwellings.
The mean gas consumption in 2021 for all dwelling types built in 2005-2021 was 93 kWh per square metre which was 83 per cent of the mean for dwellings built in 1900-1966 of 112 kWh per square metre.
Mean gas consumption decreased in 2021 compared with 2020 for all dwelling types varying from a 1.5 per cent decrease for detached houses to a 2.7 per cent decrease for semi-detached houses.
A detached house used 15,906 kWh of natural gas in 2021 which was 84% higher than the corresponding mean gas consumption for an apartment.
More energy-efficient dwellings had more floor area. A and B rated detached houses had an average of 194 square metres compared with an average of 125 square metres for detached houses with an F or G rating.
Ms Corry said: "This analysis examined households that had a Building Energy Rating (BER) and used networked gas as their main space heating fuel. The results showed that households with better energy ratings consumed less gas per square metre, but they were larger in terms of floor area.
"Dwellings with better energy ratings used less gas per square metre of dwelling floor area. Average gas consumption per square metre in 2021 varied from: 87 kWh for A and B rated dwellings; 100 kWh for C rated dwellings; 112 kWh for D rated dwellings; 118 kWh for E rated dwellings; and 120 kWh per square metre for F or G rated dwellings."
