BER stands for Building Energy Rating, this is an energy label for a house or any building. This is based on the overall efficiency of a building and the scale is from A1 (the best) to G (the worst). A1 rated homes will be the most energy-efficient and tend to have the lowest bills. It is assessed on how much energy it takes to heat a home, how efficient the heating is, the water heating, the ventilation and lighting. This will come with an advisory report. The report will indicate areas where you can improve the efficiency of the home, such as a new boiler, wall + attic insulation, upgrading windows and instaling a stove is twice as efficient as an open fireplace. The SEAI have a list of independent assessors that you can check out here