This detailed cross-section illustration depicts the heating system and airflow patterns inside a well-insulated house during winter. Snow covers the roof and trees surround the house, emphasizing the cold outdoor environment. The image highlights key components like an air source heat pump outdoor unit extracting heat from cold air, an indoor air handler circulating cool return air, and ducted warm air delivery through warm air outlets. Additionally, a high-efficiency wood fireplace produces heat that rises by convection, with chimney and flue absorbing exhaust gases. The house walls are insulated to R-22 standards, and red and blue arrows visually represent warm and cool airflows, providing clear insight into the home’s energy-efficient heating process.