Maximizing solar energy in buildings slashes winter heating costs by 80%
Solar energy can help reduce heating energy use in buildings during winter. A study in China's hot summer and cold winter zone shows that solar energy entering rooms through walls is as important as through windows for cutting heating energy. The south-facing room's wall can absorb 17% of solar energy when the outer surface has low heat transfer. By considering solar energy through walls, building heat loss can be reduced by 20-80% compared to national standards. Proper building layout can further cut heating energy use by reducing wind near south walls. Formulas are provided to estimate solar absorption through walls on sunny winter days.