The diagrams illustrate the natural circulation of air within a house and the resulting loss of heat.
Overall, cold air primarily enters through lower-level openings, while warm air escapes via vents in the upper sections, particularly in the attic, leading to significant energy inefficiency.
Outside air penetrates the house through a variety of entry points, including windows, vents, the bathroom electrical outlet, doors, and the crawl space. These openings allow cooler air to infiltrate the interior, lowering the indoor temperature and increasing the demand for heating.
In contrast, warm air rises and escapes through upper-level outlets, such as recessed lighting, the bathroom fan vent, and the plumbing stack vent. This upward movement of heated air results in considerable heat loss and reduces the overall efficiency of the house’s heating system.