Understanding the Two Most Common Gas Fuels
Whether you're connecting a new property to gas, choosing fuel for an off-grid home, or simply trying to understand your energy options, the choice between LPG (Liquefied Petroleum Gas) and natural gas is fundamental. Both are hydrocarbon fuels used for heating, cooking, and power generation — but they differ significantly in composition, storage, cost structure, and application.
What Is Natural Gas?
Natural gas is a mixture of gases extracted from underground reservoirs, primarily composed of methane (CH₄) — typically 70–90% — along with smaller amounts of ethane, propane, butane, and other gases. It is delivered to homes and businesses through a network of underground pipelines maintained by gas distribution companies.
Because it is lighter than air, natural gas that leaks will disperse upward into the atmosphere, which is a relative safety advantage in well-ventilated spaces.
What Is LPG?
LPG is a group of flammable hydrocarbon gases — predominantly propane (C₃H₈) and butane (C₄H₁₀) — that are liquefied under moderate pressure for storage and transport. LPG is a byproduct of natural gas processing and crude oil refining.
Unlike natural gas, LPG is denser than air. This means that leaked LPG can accumulate at ground level in low-lying areas — basements, trenches — creating a more serious explosion risk if not properly managed.
Side-by-Side Comparison
| Property | Natural Gas | LPG (Propane) |
|---|---|---|
| Main component | Methane (CH₄) | Propane (C₃H₈) |
| Energy content (approx.) | ~10.5 kWh/m³ | ~25.8 kWh/m³ |
| Storage | Mains pipeline | Tanks or cylinders on-site |
| Density vs. air | Lighter than air | Heavier than air |
| Availability | Urban/suburban only | Anywhere with delivery access |
| Typical application | Mains-connected properties | Rural properties, off-grid, mobile |
| Carbon emissions | Slightly lower per kWh | Slightly higher per kWh |
Energy Content: Which Is More Efficient?
LPG has a significantly higher energy density per unit volume than natural gas. This means that LPG appliances are designed with smaller burner orifices and different pressure regulators — you cannot simply switch between the two fuels without converting the appliance. Most modern gas appliances are dual-fuel convertible and come with a conversion kit for switching between natural gas (G20) and LPG (G31 for propane or G30 for butane).
Storage and Supply
Natural Gas
If your property is connected to the gas grid, natural gas is delivered on demand through the mains. There's no storage to manage, no deliveries to schedule, and billing is based on actual consumption from a meter. This is convenient and typically the lowest-cost option where available.
LPG
LPG requires on-site storage in a bulk tank (for large properties) or portable cylinders (for smaller applications). Bulk tanks are typically owned or leased from the LPG supplier and must be installed by a qualified engineer at a safe distance from buildings and boundaries. You'll need to manage your supply levels and schedule deliveries before running out.
Cost Considerations
In most markets, natural gas is cheaper per unit of energy than LPG. However, if your property is not on the gas grid, the comparison is between LPG and electricity (usually for heating via heat pumps or direct electric) — and LPG can be competitive in this context. LPG prices can also fluctuate more than mains gas, as they are more closely linked to oil market prices.
Which Should You Choose?
- On the gas grid? Natural gas is almost always the better choice — more convenient, lower cost, lower hassle.
- Off-grid rural property? LPG bulk tank is the most practical like-for-like alternative to natural gas.
- Temporary or portable use? LPG cylinders are the obvious solution — portable heaters, camping stoves, mobile catering.
- Considering the environment? Both are fossil fuels. If reducing carbon is the priority, assess whether a heat pump or other renewable technology is viable for your property.