Does natural gas require more or less oxygen than LP gas for complete combustion?

Natural gas, which is primarily composed of methane (CH4), requires more oxygen for complete combustion compared to LP gas, typically made up of propane (C3H8) and butane (C4H10). The combustion process for each fuel type involves a specific stoichiometric ratio, which is the ideal amount of oxygen needed to completely oxidize the fuel without leaving any unburned fuel or producing excess CO2 or CO.

For complete combustion, methane needs a higher volume of oxygen as it has a lower carbon-to-hydrogen ratio compared to LP gas. This means that to fully oxidize a given amount of natural gas, a greater amount of oxygen must be supplied, resulting in more combustion products. Consequently, the correct choice highlights the significant differences in combustion characteristics between the two fuel types, emphasizing the importance of ensuring the appropriate air-to-fuel ratio for efficient and safe operation in HVAC systems.