Which feature helps reduce heat transfer in a building envelope?

• A. High-performance insulation and airtight envelope
• B. Thin walls with no insulation
• C. Large unshaded glazing
• D. Gaps and leaks

Answer: (A)

Reducing heat transfer through the building envelope comes from increasing thermal resistance and blocking air leaks. High-performance insulation adds resistance to heat flow, slowing conduction through walls and roofs, while an airtight envelope minimizes drafts and air leakage, cutting convective losses and gains. Together, they significantly reduce the heat moving between indoors and outdoors, boosting energy efficiency and comfort. In contrast, thin walls with no insulation allow heat to pass easily by conduction; large unshaded glazing increases heat gain in sun and heat loss when cold; gaps and leaks create drafts that carry heat with the air.