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U Valve Testing

Overview

U-values are used to measure how effective elements of a building's fabric are as insulators. That is, how effective they are at preventing heat from transmitting between the inside and the outside of a building.

U-values can tell you how well an insulated glass unit (IGU) will hold in heated or cooled air. The lower the number, the better the insulating performance. U-values generally range from 0.1 (very little heat loss) to 1.0 (high heat loss).

As energy prices increase, and there is greater awareness of sustainability, performance measures such as U-values have become more important, and building standards (such as the Building Regulations) have required that lower and lower U-values are achieved. This has required changes in the design of buildings, both in the use of materials (such as insulation), the make-up of the building elements (such as cavity walls and double glazing), and the overall make up of a building's fabric (for example, reducing the proportion of glazing).