First, arrange a BER assessment with an SEAI-registered domestic BER assessor. The assessor visits your home to record details such as insulation, windows, heating, ventilation, renewable systems and floor area, and may ask for supporting documents. They enter the information into SEAI-approved software, which calculates the rating and produces a BER certificate and advisory report. The certificate is then lodged on the SEAI register, with the final rating depending on the information available and the assessor’s assessment. You can check the certificate details online or discuss possible improvements with the assessor.