What is solar heat gain?

• A. Heat from wind
• B. Heat from the sun's rays
• C. Heat from appliances
• D. Heat from occupants

Answer: (B)

Solar heat gain is the heat that enters a building from the sun’s energy. It happens when sunlight passes through windows or other transparent surfaces and is absorbed by interior surfaces or heats the air inside, raising indoor temperatures. This source of heat is separate from internal gains like people or appliances, and from heat brought in by wind. In design and energy calculations, solar heat gain is influenced by window orientation, glazing type and coatings, shading, and the building’s thermal mass (how surfaces store heat). It can reduce heating needs in winter but increase cooling loads in summer if not managed. Selecting the option that describes heat from the sun’s rays is the most accurate.