A BER comparison means looking at the Building Energy Ratings of two or more homes to compare their energy performance. The A-to-G ratings, energy use, carbon emissions and estimated heating costs can help indicate which property may be more efficient. However, a BER is based on standard assumptions, so actual bills can vary with the home’s size, occupants, heating habits and energy prices. You can check BER details on the official SEAI register, while a registered assessor can explain any property-specific results.