What Is Building Energy Rating (BER) & Why Is It Important?

man in high vis and safety helmet assessing a building and making notes

As we’ve become more aware of the impact that our home energy usage can have on the planet, there’s been a big focus in Ireland and the rest of the world on how we can make our homes more energy efficient. There are many different energy upgrades that can be made in a property in order to achieve this. What’s just as important as making these improvements, is measuring the impact that they are having. That’s where the building energy rating (BER) comes in. 

What Is Building Energy Rating?

A building energy rating is a certificate that rates your home’s energy performance on a scale from A to G. A-rated homes are the most energy efficient, whilst G-rated homes are the least efficient. A-rated homes tend to have the lowest bills, whilst G-rated ones require a lot more energy to heat the home, and consequently have higher bills. 

Building energy rating certificates are legally required if you are renting, buying or selling a property and provide a key insight into your home’s energy efficiency and bills. The rating is essential for indicating how much money you will spend on bills, as well as highlighting areas where the efficiency of the property could be improved. 

How Is The Building Energy Rating Calculated?

A BER assesses how much energy the property requires for heating, ventilation and lighting. The calculation is based on the number of occupants and the levels and durations of heating/hot water demand, with the rating being based on the building itself, not the usage by the occupants themselves. Assessments are made through a survey completed by a certified BER assessor. During the assessment they’ll collect a variety of information that may include:

  • Floor dimensions, room width/height and window size
  • Insulation levels within the walls, roof and floor
  • The building’s construction type 
  • Any renewable systems
  • The building’s orientation
  • Hot water systems

What Affects A Building Energy Rating?

There are many different factors that influence how energy efficient a property is, and therefore what the BER is. These factors include:

Thermal Insulation

Thermal insulation is found in the walls, attic and floors. If a home is poorly insulated then a huge amount of heat can be lost through these areas. This means that a property with low insulation levels will have greater heat loss, making it more expensive to heat to a comfortable temperature. As a result, the BER rating will be lower.

contractor installing insulation

Windows, Doors & Floor Area

A huge amount of heat in properties is also lost through the windows and doors, particularly if the windows are single-glazed and the doors are unsealed. With this in mind, a BER survey will take into account the age of windows and doors, frame types and glazing types. It will also consider floor dimensions for areas of the property that are heated.

Heating Systems

Older gas or oil boilers are a lot less efficient than new alternatives such as air to water heat pumps. New boilers and heat pumps also come with smart controls that can help you heat your home more effectively. Taking this into account, a BER assessor will take data from the home’s heating system for their calculations.The more efficient the heating system, the higher the rating will be.

Underfloor Heating With Wooden Floors

Age Of Construction / Default Values

The year in which the construction was completed is used to make estimates, where information in certain areas is lacking, for example if there is minimal information on insulation levels. These estimates are known as ‘default values’, and are used when there is insufficient information to calculate the BER. 

Light Fittings

The building energy rating will also consider the installed fixed lighting in the home, recording the type and quantity present in the property. If you use more energy efficient light bulbs, this will also lower the usage and consequently improve the BER certificate.


Renewable energy sources are another factor that will have a positive impact on your building energy rating. That’s why the likes of heat pumps, wind power and solar space heating will all be included in the assessment. 

energy field with wind turbines

Making energy upgrades in your home will have a big impact on the BER. To hear about how Pipelife’s energy efficient upgrades can improve your property’s ratings, please don’t hesitate to get in touch with us.

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