Which gas is heavier than air and often used in residential heating systems?

The answer is based on the properties of propane. Propane is indeed heavier than air, which is an important characteristic when considering its behavior in residential heating systems. When released, propane will tend to settle in lower areas because it is denser than air, creating a potential safety concern.

This characteristic is significant for technicians as it influences how propane is stored, handled, and ventilated in heating applications. Proper ventilation must be ensured to prevent propane from accumulating in confined or low-lying spaces.

In contrast, natural gas, butane, and methane do not exhibit the same weight; natural gas, primarily composed of methane, is lighter than air and disperses upward when released. Butane is also heavier than air, but it is less commonly used in residential heating systems compared to propane, which is widely available and utilized for its efficiency and performance in heating applications. Methane, while being the main component of natural gas, is not commonly referenced as being used in residential systems on its own. Thus, the choice of propane aligns with the requirements and behaviors of gases used in heating.