Natural Gas vs Propane Generators: Which Is Right for You?

The Fuel Decision

After choosing the right generator size, your next major decision is fuel type. Most residential standby generators run on either natural gas or liquid propane (LP). Both are reliable, clean-burning fuels, but the right choice depends on what is available at your property and how you plan to use the generator.

Natural Gas: The Urban and Suburban Standard

If your home is connected to a municipal natural gas line, this is almost always the easiest and most cost-effective choice.

Unlimited fuel supply. During a power outage, the natural gas grid continues to function because it does not rely on electricity. You will never run out of fuel, even during a week-long outage after a hurricane.

No on-site storage. There is no tank to install, maintain, or refill. This saves $1,500–$2,500 on installation and frees up yard space.

Lower fuel cost. Natural gas typically costs 30–40% less per BTU than propane, which means lower operating costs during extended outages and routine weekly exercise cycles.

Slightly lower power output. Natural gas has a lower energy density than propane. A generator rated at 22 kW on propane may produce 20 kW on natural gas. This is a small difference but worth noting when sizing your unit.

Propane: The Rural and Backup-Ready Option

For homes without natural gas service, propane is the clear winner. It is also preferred by some homeowners in areas where natural gas pressure drops during high-demand events.

Available anywhere. Propane is delivered by truck and stored in an on-site tank, so it works for rural properties, islands, and areas without natural gas infrastructure.

Higher energy density. Propane produces about 10% more power per unit of fuel than natural gas, which means slightly better generator performance and efficiency.

Long shelf life. Propane does not degrade over time, unlike gasoline or diesel. A full tank stays ready for years without treatment or rotation.

Tank costs and logistics. A 500-gallon above-ground propane tank costs $1,500–$2,500 installed. Underground tanks cost more but keep your yard clear. You will also need to schedule refills, which can be difficult immediately after a major storm when demand spikes.

Cost Comparison

Here is a practical cost comparison for a typical 22 kW generator running at 50% load:

• •Natural gas: approximately $1.50–$2.50 per hour of operation
• •Propane: approximately $2.50–$4.00 per hour of operation

For a 3-day outage running 18 hours per day at 50% load, natural gas costs roughly $80–$135, while propane costs $135–$215. Over a generator’s 15–20 year lifespan, the fuel savings from natural gas add up, but propane remains affordable for most homeowners.

Dual-Fuel Generators

Many modern generators offer dual-fuel capability, meaning they can run on either natural gas or propane. This is an excellent option if you have natural gas but want propane as a backup, or if you might move to a property with different fuel availability.

Dual-fuel units cost $200–$500 more than single-fuel models. The generator automatically adjusts its fuel-air mixture based on which fuel is connected.

Which Should You Choose?

Choose natural gas if: your home has an existing gas line, you want the lowest operating costs, and you prefer zero maintenance on fuel storage.

Choose propane if: you live in a rural area without natural gas, you want maximum power output, or your natural gas service has pressure concerns.

Choose dual-fuel if: you want flexibility, you plan to move in the future, or you want propane as an emergency backup to your natural gas supply.

Installation Differences

Natural gas installation is generally simpler and cheaper. The installer connects the generator to your existing gas meter with a short run of pipe. The gas utility may need to verify that your meter can handle the additional load.

Propane installation requires setting a tank, running a gas line from the tank to the generator, and coordinating with a propane supplier for the initial fill. This typically adds half a day to the installation timeline.