Building Code Administrators and Inspectors Florida Principle and Practice Licensure Practice Exam

What is the U-factor for an uninsulated metal door?

1. 0.70

2. 1.10

3. 0.50

4. 1.20

The correct answer is: 1.20

The U-factor, also known as thermal transmittance, is a measure of how effective a building component is as an insulator. The lower the U-factor, the better the material is at insulating. For uninsulated metal doors, the U-factor is typically higher because metal conducts heat poorly compared to insulated materials. In the context of metal doors, they often have U-factors that are generally above 1.0 due to their inability to retain heat. A U-factor of 1.20 indicates a higher level of heat transfer, which aligns with the properties of an uninsulated metal door. This means it allows more heat to pass through, making it less efficient in terms of energy use and thermal performance compared to insulated doors or other building materials with lower U-factors. Thus, a U-factor of 1.20 aligns well with typical values for uninsulated metal doors, highlighting their role in thermal bridging and energy loss in building design.