84% of homes built since 2020 are heated using electricity.
That compares to just 19% which were built between the year 2000 and 2004.
The CSO said that no home with a BER constructed since 2020 installed an oil boiler for the house - that compares with more than a third built 20 years ago.
The SEAI says a "BER makes the energy performance of a home visible to prospective buyers and tenants allowing them to take energy performance into consideration in their purchase or rental decision."
The lowest proportion of A-rated homes are in Leitrim - just 2% have the highest possible rating from the Sustainable Energy Authority, while the highest are in the east - Kildare, county Dublin and Meath.
Just 1% of apartments nationally had the highest marks possible, while 43% were given a BER of D or less.