Material Properties and Energy Impact

BIM for Architecture, Engineering, and Construction Curriculum

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• BIM Curriculum
• Unit 3 | Green Building Design
• Lesson 2: Material Properties and Energy Impact

Key Terms

The following key terms were used in this lesson:

R-value

A measure of thermal resistance, or insulation. Larger R-values provide greater thermal resistance. In the United States, this measure is often used to describe insulative properties of solid assemblies, such as walls and roofs.

U-value

The inverse of the R-value, the U-value measures thermal conductance\u2014how much heat transfers through a material or assembly. In the United States, U-values are typically used to describe the thermal properties of windows and skylights. Around the world, U-values are also used to describe the thermal properties of solid assemblies (rather than R-values).

Thermal Zone

A building area or group of rooms that will be treated as a single unit for heating and cooling analysis and design. Each thermal zone can have its own use properties (such as number of occupants, type of use, and time of use) and heating and cooling system.

Thermal Comfort Range

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The range of temperatures that is considered acceptable for users of a space. When the temperature dips below the bottom of the range, heating devices are used to warm the space. When the temperature climbs above the top of the range, cooling devices are used to bring the temperature down.

Predicted Mean Vote (PMV)

A measure of thermal comfort that predicts what a large group of people would say about the temperatures being experienced within a space. It is typically measured on a scale from +3 (people feel hot) to -3 (people feel cold).

Predicted Percent Dissatisfied (PPD)

A measure of thermal comfort that predicts the percentage of people in a space that would be dissatisfied with the temperature they are feeling in that environment.