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.
A U-Value calculation is a computer-based assessment that measures the total thermal resistance of a structure. Building Regulations/Standards continue to tighten the requirements of U-Values, with lower limits provided to ensure that building elements, materials and fabric are considered throughout the design and construction process.
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. They are useful as it is a way of predicting the composite behaviour of an entire building element rather than relying on the properties of individual materials.
Where compliance is required for whole-building energy performance (completely new buildings), U-Values are used within Standard Assessment Procedure (SAP) calculations for new dwellings, and also Simplified Building Energy Modelling (SBEM) calculations for new non-dwellings.
QuinnRoss Energy U-value calculations are carried out in accordance with BRE443: Conventions for U-value Calculations and can be submitted with the necessary Building Control applications to demonstrate full compliance.
As qualified SAP assessors, we can carry out U value calculations for any building in England, Wales and Scotland and send you back the documents you require.
What’s a U-value?
A U-value is the rate of heat transfer through a building structure, taking into account the temperature difference across said structure. I.e. it outlines how much heat your building loses through its floors, walls, roofs and glazing. The lower the U-value, the less heat it will lose.
Why is it important?
Its very important. All newly built buildings have to achieve target U-values for floors, walls, roofs and windows. If these are not achieved the building will fail Building Regulations, a legal requirement, and cannot be built.
They also heavily influence the amount of heating energy required to maintain the internal temperatures. Poor U-values will compromise the buildings CO2 targets that it has to comply with.
How do you calculate it?
Again, with approved software that QuinnRoss Energy is fully accredited to use and we have been helping and advising clients for decades on how to best manage their building performance.