Leitrim has one of the lowest proportion of A-rated homes in the country.
New data shows that just 6% of properties in Donegal have the highest energy rating.
A Building Energy Rating, or BER, calculates the energy efficiency of a home and can be used as an indicator of the running costs and carbon emissions associated with heating a house to a comfortable level.
The figures from the CSO also show that Leitrim has one of the highest rate G-rated homes nationwide.
