Certified Energy Auditor Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Low-emissivity (low-e) coatings on glass are designed to reflect infrared radiation while allowing visible light to pass through. This property is particularly significant in regulating heat transfer. By reducing the amount of infrared radiation that can pass through the glass, low-e coatings effectively minimize the heat gain from the sun in warmer months and reduce the heat loss from indoor spaces during cooler months.

The low-e coating works by reflecting long-wave radiation (which is thermal energy) back into the room or outside, depending on the season, which helps maintain temperature control within buildings. This reflects thermal energy that could otherwise be absorbed by the glass and transferred inside, thus improving energy efficiency.

The other options, while they discuss aspects of window performance, do not accurately describe the key benefit of low-e coatings related to heat transfer. For instance, low-e coatings do not inherently increase heat gain; their purpose is to reduce it. They also do not primarily affect visible light transmission negatively, as they are designed to allow significant visible light to pass through. Lastly, though preventing condensation can be a secondary benefit of improved window insulation, it is not the main function of low-e coatings in relation to heat transfer.