Question: is butane heavier than propane?
Answer: Butane gas weighs 2.5436 kg/m³ whilst air weighs 1.225 kg/m³. Propane is 1.55 times heavier than air. Propane gas weighs 1.898 kg/m³ vs air at 1.225 kg/m³. (All at 15°C and 1 atm).