LPG (Liquid Petroleum Gas) is a mixture of propane and butane which is stored under moderate pressure. Due to LPG being roughly 250x denser as a liquid than a gas, storage of the fuel is made more efficient as you're able to keep a large quantity in a small space! It serves as an alluring option for the more rural households who happen to be unreachable for the main gas network. 

As well as this, LPG has lower carbon emissions than most (if not all) fossil fuel options that these particular homeowners have to choose from, knocking a fair chunk of 20% less CO2 per kWh than regular heating oils!