FREQUENTLY ASKED QUESTIONS
A Building Energy Rating (BER) Certificate calculates the energy performance of a building on a scale from A to G. A-rated houses are the most efficient and G the least efficient. All new dwellings and houses offered for sale or lease require a BER.

There are two types of BER, a provisional and a final BER. A provisional BER is based on plans and specifications of a new building and is valid for 2 years. A final BER is issued on completion of a new building and is valid for 10 years once there is no material change to that building. Existing buildings can also have a BER assessment carried out to determine their efficiency, and that certificate is also valid for 10 years.
BER is calculated by assessing the major components of the building in detail. The u-values of walls, roofs, floors, windows, and doors are all calculated and the efficiency of the heating and hot water systems. Mechanical ventilation, air tightness, energy-efficient lighting, and renewable technologies are all assessed and combined in the calculation to determine the building's energy rating. Once the BER is calculated, a large amount of info becomes available, including annual energy use for fans, water heating, heat pumps, space heating, lighting, etc.
If you are thinking of building a house, understanding the concept of U-Values is very important. A U-Value is a measure of heat loss in a building element such as a wall, floor or roof. It can also be referred to as an ‘overall heat transfer co-efficient’ and measures how well parts of a building transfer heat. This means that the higher the U-Value the worse the thermal performance of the building envelope. A low U-Value usually indicates high levels of insulation.
However, merely meeting these standards may not be enough to comply with the building regulations. If the building is poorly oriented or has a large proportion of glazing, this may require a further improvement and compensation in terms of U values, air tightness and thermal bridging so as to meet the overall energy requirements. See Building Regulations 2024, Part L for more information.
Part L is one of the numerous Building Regulations that your house must comply with upon completion. It specifically addresses heating and hot water systems. This comprehensive document must be adhered to by your builder, plumber, and heating designer to ensure that the minimum requirements are met and that your heating system complies with building regulations.
The current Part L document outlines the maximum allowable energy usage and carbon emission levels for homes. It mandates that all new buildings incorporate renewable energy technology to reduce reliance on fossil fuels for heating or to lower primary electricity consumption. Heat pumps are among the most popular renewable energy sources used for heating and hot water.
For existing dwellings, the requirements shall be met :
limiting heat loss and, where appropriate, availing of heat gain through the fabric of the building
controlling, as appropriate, the output of the space heating and hot water systems
limiting the heat loss from pipes, ducts and vessels used for the transport or storage of heated water or air
providing that all oil and gas fired boilers installed as replacements in existing dwellings shall meet a minimum seasonal efficiency of 90 % where practicable.
For new dwellings, the nearly zero energy performance requirements shall be met by:
providing that the energy performance of the building is such as to limit the calculated primary energy consumption and related carbon dioxide (CO2) to that of a nearly zero energy building within the meaning of the Directive insofar as is reasonably practicable, when both energy consumption and carbon dioxide (CO2) emissions are calculated using the Dwelling Energy Assessment Procedure (DEAP) published by Sustainable Energy Authority of Ireland
providing that, the nearly zero or very low amount of energy required is covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby
limiting the heat loss and, where appropriate, availing of heat gain through the fabric of the building
providing and commissioning energy efficient space and water heating systems with efficient heat sources and effective
providing that all oil and gas fired boilers shall meet a minimum seasonal efficiency of
providing to the dwelling owner sufficient information about the building, the fixed 6 building services, controls and their maintenance requirements so that the building can be operated in such a manner as to use no more fuel and energy than is reasonable
Heat Recovery Ventilation (HRV) is an energy recovery ventilation system that uses sophisticated heat and air exchangers between the inbound and outbound air flow. HRV systems provide fresh air and improved climate control, while saving energy by reducing heading demands. There would be no benefit to install a HRV system in an old house with natural (draughty) ventilation. These systems only work effectively in houses that are adequately air tight and insulated.
What Is Air-Tightness?
Air-tightness is the control of air flow through the external envelope of a building. If a building is air-tight, air will not leak from the structure via common paths such as:
Ceiling and Wall Junctions
Plaster Board Joints
Doors
Windows
Service Entry Points
Any leaks would create discomfort and heat would be lost, which would result in the heating system having to compensate for heat loss.
Due to EU Regulations, HFC (hydrofluorocarbons) refrigerants are being phased out. This includes R32 & R410A. Gases such as R290 & R454B will be the replacement gases so our customers will not be affected.
We provide advice to help you choose the best system for your needs. Our experts guide you through options, explaining the benefits and features of different systems, ensuring you make an informed decision. Whether you're interested in traditional heating solutions or the latest energy-efficient technologies, we ensure you understand the choices available.