Key Takeaway: What Type of Gas Do Whole-Home Generators Use?
Most home standby generators run on natural gas or liquid propane. Natural gas connects to a utility line, while propane is stored in an on-site tank. The best choice depends on your home’s fuel access, outage planning needs, local infrastructure and whether you want continuous utility-supplied fuel or stored fuel you manage yourself.
Like any major home investment, choosing a standby generator comes with a lot of questions. For many homeowners, the first one is simply: Where do I even start?
Power output tends to be the top concern, but fuel type comes in close second—and for good reason. Most whole-home generators run on natural gas or liquid propane. Both are reliable options, but they work differently when it comes to fuel supply, runtime and long-term planning.
Understanding those differences early on can make the rest of the buying process a lot easier.
Not sure what size system your home may need? Use the Generator Sizing Tool to estimate your home’s power requirements before moving on to fuel and installation planning.
Fuel can’t be an afterthought. It’s a key factor that impacts everything, from installation and long-term costs to runtime and maintenance planning.
Some homeowners prioritize the convenience of a continuous natural gas connection. Others prefer the independence of on-site propane storage, especially in rural areas where natural gas service may not be available.
These decisions also connect directly to generator sizing and household power needs. A larger home with more appliances and HVAC equipment, for example, will typically consume fuel faster than a smaller backup setup focused on essentials. Outage expectations matter, too. Preparing for a few hours without power can look very different from planning for multi-day weather events.
If you’re looking for a more hands-off option, this is it. Natural gas generators connect directly to your home’s existing gas utility line. Since fuel is supplied continuously through the utility system, you don’t have to store fuel on-site or manually refill the tank under normal operating conditions.
For many homeowners, that’s a major advantage. There’s no tank to monitor and no need to schedule refuels after a storm. In general, natural gas systems tend to require less fuel management over time.
That said, natural gas depends on your local utility infrastructure. While gas systems generally remain operational during outages, earthquakes, severe weather, other disasters might interrupt service indefinitely.
Instead of relying on a gas utility line, propane generators use fuel stored on-site in a dedicated tank installed on the property. This setup gives homeowners more independence from utility infrastructure, making propane a common choice in rural areas without natural gas service.
Because the fuel supply is stored on-site, runtime depends on tank size and fuel levels. Larger tanks can support longer operation, but homeowners still need to plan for refills during extended outages.
That planning becomes especially important after major storms, when high regional demand can create delivery delays or refill bottlenecks. Propane systems also require space for tank installation, which may influence placement and permitting considerations.
Still debating? Take a look at the table below for a side-by-side comparison.
| Factor | Natural Gas | Propane | What it means for homeowners |
|---|---|---|---|
| Fuel source | Utility gas line | On-site propane tank | Fuel availability depends on local service and home setup |
| Storage | No on-site tank managed by homeowner | Requires tank storage | Propane requires more active fuel planning |
| Runtime planning | Tied to gas service availability | Tied to tank size and usable fuel level | Both require professional planning for long outages |
| Best fit | Homes with existing natural gas service | Homes without natural gas or in rural areas | Availability often drives the choice |
| Installation considerations | Gas line and meter capacity assessment | Above vs below ground tank placement and capacity | Professional installation guidance is important |
| Disaster considerations | Service can be interrupted or shut off in some events | Stored supply is finite and refill access can be delayed | No fuel source is risk-free in every emergency |
| Ongoing logistics | Less homeowner-managed fuel handling | Tank checks and refill scheduling | Propane requires more ongoing fuel management |
| Cold weather considerations | Generally tied to utility service reliability | Propane vaporization can be affected by cold | Cold climates may need extra propane planning |
| Resupply considerations | Utility dependent | Delivery dependent | Extended outages should be planned before storm season |
All Generac whole-home backup generators are dual-fuel capable, meaning they can be configured to run on either natural gas or liquid propane.
Natural gas and propane have different pressure and combustion requirements, so switching fuels typically requires professional configuration during installation. Some units are built as dedicated systems for one fuel source, while others may allow approved field conversion.
Because fuel setup affects safety and warranty coverage, any conversion or configuration change should always be handled by a qualified installer.
Fuel consumption depends on several factors, including generator size, electrical load, fuel type, weather conditions, maintenance and how long the generator runs during an outage.
What you choose to power also makes a difference. A generator supporting only essential circuits will typically use less fuel than a system running most or all of the home, especially when large appliances or HVAC systems are involved.
At Generac, we publish approximate fuel consumption rates for our home standby generators, but actual usage can vary by model and operating conditions. Homeowners should always reference their generator’s spec sheet, installation manual or fuel data decal for exact numbers. Your home's gas meter should also be capable of supporting both generator fuel flow and other household gas loads at the same time.
Generac Mobile Link makes it easy to keep an eye on your system after installation. You can check generator status, monitor runtime, receive maintenance reminders and connect with service support—all from your phone.
If you have a propane-powered generator, Generac's optional Fuel Monitor can also display propane tank levels in the app, giving you one more way to stay prepared for the next outage.
If your generator runs on propane, your tank size has a direct impact on runtime. A larger tank will keep you going longer, but it’ll need a refill eventually. Regional demand for fuel tends to spike in the days after major storms, so it’s best to plan for possible shortages or delivery delays. Some homeowners choose to establish a relationship with a local propane provider before outage season starts. That way, they’re already set while others fight for their spot on the delivery schedule.
Planning is easier when you can keep a close eye on your fuel levels. Our monitor allows you to view tank levels through Mobile Link. It also sends low-fuel alerts and tracks usage trends—all helpful to know as you plan for extended outages.
A few simple load-management habits can also help stretch your reserves when fuel is scarce. Running only essential appliances, staggering heavy electrical loads and limiting unnecessary energy use can reduce overall fuel consumption.
Fuel usage depends on generator size and load. A typical 22kW home standby generator might use roughly 2–3 gallons of propane per hour at half load, and closer to 3–4 gallons per hour at full load. Actual usage will vary based on what you’re powering and how hard your system is running.
A 500-gallon tank is usually filled to about 80% for safe operation, giving you roughly 400 usable gallons. For average household loads, that translates to several days of runtime, though heavier usage (like running HVAC continuously) will shorten that window.
Yes. In very cold conditions, propane can vaporize more slowly, which may limit performance if demand is high. Proper tank sizing and placement help reduce this risk, especially in colder climates where sustained winter outages are a concern.
Yes, but it isn’t always straightforward. Switching between natural gas and propane typically requires specific configuration changes and professional service. That’s why it’s best to choose your primary fuel source during the planning stage rather than after installation.
It depends on local utility rates and propane costs. Natural gas is typically billed through a utility meter, while propane pricing includes delivery and refilling logistics. Instead of focusing only on cost, most homeowners find it more useful to weigh price alongside availability and reliability.
