14. A wall cavity with a reflective surface has a higher R -value than just the cavity Explain why this occurs. __

wall cavity with a reflective surface has a higher R-value than a simple cavity because the reflective surface reduces heat transfer via radiation. Here's a breakdown:* **R-value:** Measures a material's resistance to heat flow. Higher R-value means better insulation.* **Heat Transfer Methods:** Heat transfers in three ways: conduction, convection, and radiation.* **Cavities and Convection:** A simple air cavity reduces heat transfer primarily by limiting conduction. Air is a poor conductor. However, convection currents can still form within the cavity, where warmer air rises and cooler air falls, carrying some heat across the space.* **Reflective Surfaces and Radiation:** A reflective surface within the cavity minimizes radiant heat transfer. Instead of absorbing heat and then re-radiating it, the reflective surface bounces the radiant heat back towards its source. This significantly reduces the amount of heat that crosses the cavity.Therefore, by addressing radiation in addition to conduction and minimizing convection, the reflective cavity achieves a higher overall resistance to heat flow and thus a higher R-value.