What is a key principle of passive solar design?

• A. Aligning the building to maximize winter solar gain while using shading and insulation to minimize summer overheating
• B. Maximizing glass area on east and west facades without shading
• C. Relying solely on mechanical cooling in summer
• D. Eliminating insulation to reduce construction costs

Answer: (A)

Passive solar design uses the sun to regulate a building’s temperature: capture warmth from the sun in winter and prevent excessive heat in summer. The best principle is to orient the building to maximize winter solar gain with south-facing windows and use shading and insulation to keep the space comfortable in summer. Large south-facing glazing lets in sunlight when it’s low in the sky, and architectural features or vegetation can shade the building when the sun is higher, reducing overheating. Insulation helps minimize heat loss in cold conditions and limits unwanted heat gain when outdoor temperatures rise, boosting overall energy efficiency. Glazing on east and west without shading tends to cause overheating morning and afternoon; relying solely on mechanical cooling ignores the benefits of passive design; and removing insulation undermines energy performance.