Once you’ve decided on a standby generator, the next decision tends to stop homeowners cold: natural gas or propane? It sounds simple until you realize the answer depends less on which fuel is theoretically better and more on what’s available at your address, how your home is sized, and what the generator needs to carry during a serious outage. In Montgomery County, that question has a genuinely variable answer. The wrong assumption early on can mean a generator that’s undersized, a tank that won’t fit the lot, or a fuel source that isn’t even available at the property.
PECO serves natural gas to most of the county, but “most” isn’t all. About 52% of Montgomery County homes use natural gas as their primary heating fuel, which means roughly 48% don’t have a gas line. Rural sections and some older developments fall outside PECO’s gas distribution territory entirely. That single fact changes the calculation for a meaningful share of local homeowners. We’ve been handling generator installation in Montgomery County for over 20 years, and the fuel question comes up at every site visit. Here’s how we walk through it.
How Each Fuel Gets to Your Generator
The delivery mechanism for each fuel is fundamentally different, and that difference shapes nearly every other comparison.
Natural gas arrives through underground utility lines managed by PECO. When a generator runs on natural gas, it taps the same supply already serving the furnace or stove. There’s no tank to install, no supplier to schedule, and no on-site storage to manage. As long as the gas main runs to the property, the hookup is straightforward.
Propane works differently. A dedicated tank (typically ranging from 250 to 1,000 gallons depending on generator size and expected runtime) is installed on the property and filled by a delivery supplier. One advantage is that propane stores indefinitely without degrading, so a full tank before storm season stays usable. Homeowners who don’t currently have a gas line should verify PECO service availability at their address before assuming natural gas is an option.
Power Output & What the Derate Means for Your Home
Both fuels power the same generators, but they don’t deliver the same output. Propane carries approximately 2,500 BTUs per cubic foot. Natural gas carries around 1,000 BTUs per cubic foot. Because of that energy density difference, most Generac standby units carry two distinct output ratings: a higher rating on propane and a lower one on natural gas. The reduction from the higher rating to the lower one is called a natural gas derate.
For many homeowners, the derate is a footnote. For others, it determines which generator size they need. In Montgomery County’s climate, a whole-home standby generator faces peak demand in both summer, when central air conditioning runs hard, and winter, when heating loads are sustained. A generator sized against the headline specification without accounting for the natural gas derate can fall short under real load conditions. A proper load calculation (performed as part of the installation process) factors in the fuel-specific output rating and selects the right unit for the actual fuel being connected.
Runtime, Fuel Access, & What Happens During a Long Outage
Runtime is where natural gas and propane diverge most sharply in practice.
A natural gas generator runs indefinitely as long as the PECO line is intact. No refueling, no scheduling, no watching a tank gauge during a multi-day outage. For most suburban Montgomery County homes already on gas service, that continuity is the strongest argument for staying with natural gas.
A propane generator runs until the tank runs low. Tank size and generator load determine how long that takes; a properly sized tank can sustain several days of continuous operation. Propane can also be pre-filled before a forecasted storm, giving homeowners some control over their fuel reserve in a way that natural gas doesn’t allow. And unlike natural gas, propane’s on-site storage is completely independent of PECO’s network. That means the generator can keep running even if the gas utility itself is disrupted. That’s the primary reason some Montgomery County homeowners choose propane even when a gas line is already available at the house.
Installation, Cost, & Pennsylvania Permit Requirements
Both fuel paths require permits. Standby generator installation in Pennsylvania requires a building and electrical permit under the Pennsylvania Uniform Construction Code (UCC). Fuel system connections (whether natural gas or propane) require separate permits and inspections under Pennsylvania plumbing and mechanical codes. Skipping the permit process isn’t an option, and a contractor who suggests otherwise isn’t one we’d recommend.
On the natural gas side, installation is straightforward when a line already serves the home. The generator connects to the existing supply, and a licensed technician manages the permit and inspection. Extending a new gas main to a property that lacks service is a different matter. It means coordinating with PECO and can add substantial cost and lead time to the project.
Propane installation requires siting a tank that complies with Pennsylvania 34 Pa. Code Chapter 13, which sets a 10-foot setback from a residential property line for LPG containers. Under the state’s preemption provision, individual Montgomery County townships can’t impose setback requirements stricter than that 10-foot standard. This matters on the smaller suburban lots common across the county, where available siting locations are sometimes limited. Navigating those setbacks is part of the permit process, and it’s something we assess during the initial site visit before a proposal is written.
Which Fuel Is Right for Your Montgomery County Home
There’s no universal answer, but the decision framework is fairly clear once you know your situation.
Gas Line Already Connected
Natural gas is typically the lower-maintenance, lower-fuel-cost path for suburban Montgomery County homes in PECO territory. No tank to manage, no delivery to schedule, and no storage footprint on the property. It’s the most common choice we install in the county.
No Gas Line at the Property
Propane is a fully capable standby fuel, not a compromise. Homeowners in this situation should also check whether their neighborhood qualifies under PECO’s Natural Gas Neighborhood Pilot Program, which received Pennsylvania Public Utility Commission approval for a five-year extension with active funding through 2029 to extend gas mains into currently unserved areas. If a future connection is realistic, some homeowners prefer to install propane now and revisit fuel options later.
Gas Line Available but Grid Independence Matters
For homeowners who’ve lived through extended outages where the gas network was compromised (or who simply want a backup system that doesn’t share a single point of failure with the grid) propane is worth the added installation complexity.
Both Fuels Work. the Right One Depends on Your Property.
Natural gas and propane both power reliable whole-home standby generators. Neither is inherently superior; the right answer comes from your address, your lot, your load, and what you need the system to do under pressure. What changes the outcome is a site assessment that accounts for all of those factors before a generator is specified.
Power Watch Systems is a Generac Power Pro Elite+ installer with over 20 years of residential generator installation in Montgomery County. We handle site assessment, load calculation, permitting, and fuel system connection for either fuel choice. If you’re ready to work through the fuel decision for your home, reach out to us at (610) 890-7693.