Kildare has the highest number of homes with the best energy rating.
It's followed by county Dublin and Meath, according to the CSO.
20 % of homes in Kildare which have been tested for a BER rating were given an A standard, while Meath and county Dublin have 19% and for Wicklow it's 15%.
The Building Energy Rating calculates a house's efficiency.
Roscommon and Leitrim have the highest proportion of G ratings - which is the worst awarded.
Both counties have 12% G rated - followed by Tipperary on 11, and Mayo and Westmeath with 10%.
Longford and Leitrim have the fewest BER ratings, while Dublin's postal districts have the most with 229,000.
C2 and C3 are the most common ratings nationally at 12%.
In total over 1 million BER ratings have been given out since 2009.
Daina Moorehouse On The Brink Of Medal After Two Victories In Brazil World Cup
Wicklow Households Encouraged To Explore Grants To Lower Energy Bills
New Equipment To Support Disabled Water Sports Users In Accessibility Boost For Bray Harbour
Dominant Daina Moorehouse Into World Cup Last 16 After Opening Brazilian Bout
Greystones E-Bike Scheme Flourishing With Over 12,000 Recorded Trips