Which of the following is NOT a cause of pressure differences in a home?

The solar effect is not typically considered a direct cause of pressure differences in a home. While solar radiation can influence temperature variations within a space—leading to warmer surfaces and altered thermal behavior—it does not generate a pressure difference on its own. Pressure differences are primarily caused by more dynamic factors such as the stack effect, where warm air rises and creates a lower pressure at the bottom of the building, and wind effects, which can cause variations in pressure on different sides of a structure. Temperature variations can also contribute to pressure differences as air density is affected by temperature changes. Thus, while solar gain can play a role in the thermal environment of a home, it does not directly create pressure differences like the other factors listed.