Archives: Definitions

The Energy Saving Trust (EST) is an independent, UK-based organisation dedicated to promoting energy efficiency, reducing carbon emissions, and supporting sustainable energy use in homes and businesses. It provides impartial…

 The G-Value, or solar gain coefficient, quantifies the amount of solar energy that passes through a window or glazing system. It is expressed as a decimal fraction, where a higher…

The U-value is a measure of thermal transmittance, indicating how much heat is lost through a building element, such as walls, roofs, or windows. It is expressed in watts per…

The Window Energy Rating (WER) is a classification system that assesses the energy efficiency of windows. It operates on a scale from ‘A’ (most efficient) to ‘G’ (least efficient), similar…

Trickle ventilation refers to a method of providing background ventilation in buildings through small openings, typically incorporated into windows or walls. This system allows a controlled amount of fresh air…

Trickle flow refers to a low continuous extraction rate of air used in ventilation systems, particularly in continuous fan units such as Decentralised Mechanical Extract Ventilation (dMEV), Mechanical Extract Ventilation…

Thermal efficiency refers to the ratio of useful heat output from a heating device, such as a gas boiler, to the energy input from the fuel used. It is a…

Retrofit refers to the process of adding new technology or features to older systems, buildings, or equipment. In the context of the UK house building and retrofit sectors, it typically…

The Fabric-First Approach is a strategy in the retrofit sector that prioritises enhancing the building’s fabric—its walls, floors, roofs, windows, and doors—before considering other energy efficiency measures. This approach is…

EC04 is a term used in the UK house building and retrofit sectors to refer to a specific energy efficiency measure or standard. It is part of the broader framework…