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A natural gas generator is the closest thing to set-and-forget backup power a homeowner can buy. Bolted to a concrete pad beside the house and piped into the same gas service that feeds your furnace, it starts on its own when the grid drops and keeps going for as long as the gas flows. That convenience comes with a large installation bill and some trade-offs people rarely hear about in the showroom. This explainer covers how natural gas standby generators work, their real advantages and drawbacks, and a line-by-line look at what installation typically costs.
How a natural gas standby system works
The generator is a liquid- or air-cooled engine in a weatherproof enclosure. An automatic transfer switch (ATS) monitors utility voltage. When power fails, the ATS signals the generator to start, waits a few seconds for stable output, then transfers your circuits from the grid to the generator. When utility power returns and stabilizes, it switches back and lets the engine cool down before shutting off. Once a week or once a month, the generator runs a short self-test, called exercise mode, to keep itself ready. Generac, Kohler, Champion and Briggs & Stratton are among the familiar names in this segment.
The advantages
No fuel to store or haul
This is the headline benefit. There are no gas cans, no stabilizer, no refueling at 2 a.m. in a storm. Natural gas does not go stale, so a generator that sits unused for months will still start.
Automatic operation
Power returns to your home within seconds to a minute, whether you are home or away. That matters for sump pumps, medical equipment, freezers and homes that would otherwise freeze.
Cleaner combustion
Natural gas burns cleaner than gasoline, meaning less carbon buildup and generally longer service intervals. It still produces carbon monoxide, which is why placement rules matter.
The drawbacks
Lower output on natural gas
Most standby generators are rated on both propane and natural gas, and the natural gas rating is typically lower, often by about 10 percent. A unit sold as 24 kW on propane may produce closer to 21 or 22 kW on natural gas. Always size using the natural gas figure.
Gas service is not guaranteed
Natural gas usually keeps flowing during electrical outages, but earthquakes, major floods and pipeline incidents can interrupt it. Utilities can also shut off gas to damaged areas. In earthquake-prone regions, some owners choose propane for independence.
Meter and line capacity
A 20 kW-class generator may demand roughly 200 to 330 cubic feet per hour at full load. Many residential meters and gas lines were sized only for a furnace, water heater and range. An upgrade may require the utility to swap the meter or raise delivery pressure, which can add weeks and cost.
Ongoing costs
Annual maintenance visits commonly run $150 to $400, and exercise runs consume a small amount of gas each month. During long outages, fuel costs can be significant because the generator runs 24 hours a day.
What installation typically costs
Costs vary with region, home size, distance from the meter and electrical panel, and permitting. The table shows common ranges for a 20 to 26 kW whole-home system; get at least three local quotes.
| Cost component | Typical range | Notes |
|---|---|---|
| Generator unit (20–26 kW) | ~$5,000–8,000 | Larger or liquid-cooled units cost more |
| Automatic transfer switch | ~$600–2,000 | Service-rated whole-home ATS at the higher end |
| Electrical labor and materials | ~$1,500–4,000 | Depends on panel location and wire run |
| Gas line run and connection | ~$500–2,500 | Longer runs and larger pipe raise cost |
| Concrete or composite pad | ~$100–600 | Some units ship with a composite pad |
| Permits and inspections | ~$100–800 | Electrical, gas and sometimes zoning |
| Meter upgrade (if needed) | ~$0–1,500+ | Set by the utility; sometimes free |
| Typical installed total | ~$10,000–20,000 | Complex installs can exceed this |
Placement and safety rules
Standby units are designed to sit outdoors close to the home, but manufacturers and local codes specify minimum clearances from windows, doors, vents and air intakes, commonly around 5 feet from openings and sometimes more, plus clearance from property lines. These are different from the 20-foot guideline for portable generators, which lack engineered enclosures and exhaust routing. Never enclose a standby generator in a shed or place it under a deck. Install CO alarms inside the home regardless. The transfer switch must be installed by a licensed electrician and the gas connection by a licensed gas fitter or plumber, with permits pulled.
Is it worth it?
A natural gas standby generator makes the most sense for homes in areas with frequent or long outages, households with medical equipment or sump pumps that cannot fail, homes that are often empty, and owners who simply do not want to manage fuel. For occasional short outages, a portable generator with an interlock kit or a large power station may deliver most of the benefit at a fraction of the price.
FAQ
How much natural gas does a standby generator use during an outage?
It depends on load. At half load, a 20 to 24 kW unit may use roughly 150 to 250 cubic feet per hour, or about 1.5 to 2.5 therms. Over a 24 hour day, that can be 35 to 60 therms, so multiply by your local rate.
Can I install a natural gas generator myself?
Not legally in most places, and not safely without licensed training. Gas and electrical connections require permits and inspections, and many manufacturers require authorized installation for the warranty to apply.
Bottom line
Natural gas standby generators offer automatic, fuel-free backup power, at the price of a $10,000 to $20,000 installation, a modest output penalty, and dependence on gas service staying up. Size by the natural gas rating, confirm your meter can supply it, and budget for annual maintenance. For households that cannot tolerate outages, few upgrades deliver more peace of mind.
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