What unique characteristic does propane have compared to natural gas?

Propane has a unique characteristic compared to natural gas in that it has a higher density. This means that propane is heavier than air, while natural gas is lighter than air. This density difference impacts how each gas behaves when released into the atmosphere; propane tends to accumulate in low-lying areas, while natural gas disperses upwards. This fundamental difference is crucial for safety and installation practices in gas fitting and appliance design. The higher density of propane also contributes to its energy content, allowing for more BTUs (British Thermal Units) per volume compared to natural gas, although discussing BTU content brings us back to the context of their energy characteristics rather than a direct comparison of density.