Building Energy Ratings (BERs) provide a measure of the building's overall energy efficiency and its environmental impact. Buildings that are more energy efficient use less energy, save money and help protect the environment. The BER Certificate has a scale of A-G, A-rated homes are the most energy efficient and G the least efficient.

Building Energy Ratings (BERs) makes the energy performance of a home visible to prospective buyers and tenants and enables them to take energy performance into consideration in their next house purchase or rental decision. A seller or landlord must provide a BER to prospective buyers or tenants when a home is constructed, sold or rented. There are fines of up to €5,000 for non-compliance with the regulations.

The Building Energy Rating (BER) for dwellings must be produced following an energy assessment undertaken by a qualified assessor. The BER is calculated in accordance with a national assessment methodology established under the European Communities (Energy Performance of Buildings) Regulations (S.I. No. 666 of 2006). On completion, a copy of the certificate is lodged on a national register.

A BER is based on the characteristics of major components of the dwelling (wall, roof and floor dimensions, window and door sizes and orientations) as well as the construction type and levels of insulation, ventilation and air tightness features, the systems for heat supply (including renewable energy), distribution and control, and the type of lighting. It covers annual energy use for space heating, water heating, ventilation, lighting and associated pumps and fans, calculated on the basis of a notional standard family with a standard pattern of occupancy.

The energy performance is expressed as:

(a) primary energy use per unit floor area per year (kWh/m2/yr) represented on an A to G scale (see BER certificate); and

(b) associated Carbon Dioxide (CO2) emissions in kgCO2/m2/yr (see BER Certificate)

A BER is valid for up to 10 years provided that there is no material change to the dwelling that could affect its energy performance. The maximum term of validity of a Provisional BER is 2 years.

New homes offered for sale off plans also require a BER. In these cases, a Provisional BER will be issued based upon the design drawings and building specifications. When the home is completed, a BER based on an assessment of the final drawings and building specifications, which represent the house as constructed, is required. This BER must be supplied by the builder/developer on completion of any such homes sold off plans.