Mean gas consumption decreased last year compared with 2020 for all dwelling types, according to data from the Central Statistics Office (CSO).
The decrease varied from a 1.5 per cent decrease for detached houses to a 2.7 per cent decrease for semidetached houses.
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.
A detached house used 15,906 kWh of natural gas in 2021 which was 84 per cent higher than the corresponding mean gas consumption for an apartment.
Separately, the CSO data showed 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.
Mean electricity consumption decreased in 2021 compared with 2020 for apartments and mid-terrace houses but it increased for end-of-terrace houses, semidetached 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.