Standby Generator Guide: Whole-Home Backup Power

What Is a Standby Generator?

A standby generator — also called a whole-home or automatic backup generator — is a permanently installed unit that sits outside your home, wired directly into your electrical system, and starts automatically within seconds of a power outage. Unlike a portable generator, which you wheel out, fuel, and start by hand, a standby unit is always ready. It runs on your home's existing fuel supply, typically natural gas or propane, so there is no gasoline to store and no tank to fill mid-storm.

For homeowners in areas prone to hurricanes, ice storms, or grid failures, a standby generator turns an outage from an emergency into an inconvenience. The refrigerator stays cold, the sump pump keeps running, the furnace and well pump keep working, and the lights stay on. For households that depend on electricity for medical equipment, heating, or water, that reliability is the main reason to buy.

How a Standby Generator Works

A standby system has three main parts: the generator, an automatic transfer switch, and the fuel supply.

The generator is mounted on a concrete pad outside the home and connected to the fuel line. The automatic transfer switch is installed between the utility meter and your electrical panel. It monitors utility power around the clock. When it detects an outage, it starts the engine automatically — usually within 10 to 30 seconds — and switches the house over to generator power. When utility power returns and stabilizes, the switch transfers the home back to the grid and shuts the generator down after a brief cool-down period. You never touch anything.

Most standby units also run a weekly self-test of 10 to 20 minutes, which keeps the engine lubricated, charges the battery, and confirms the system will start when you need it.

Natural Gas vs Propane Fuel

Natural gas is the most common fuel for standby generators because it is piped directly to the home. There is no tank to fill and no fuel to store, and the supply is effectively unlimited during an outage — as long as the gas utility keeps serving your neighborhood. The downsides: adding a new gas line can be expensive, and natural gas contains slightly less energy per cubic foot than propane, so output runs a little lower.

Propane is stored in an above-ground or underground tank on your property. It burns cleanly, and it stores indefinitely, which is a real advantage for emergency preparedness. But you must monitor the tank level and keep it filled, and during a long regional outage, propane deliveries can be delayed. Consumption depends on load: at half load, a typical whole-home unit uses roughly 1.5 to 3 gallons of propane per hour, so a large tank carries you through a multi-day outage comfortably.

Which should you choose? If you already have natural gas, it is usually the cheapest and easiest long-term option. If you don't, propane gives you energy independence. Some generators ship configured for one fuel and can be converted to the other, so check the fuel type and consumption specs — you can look them up on GeneratorDatabase (generatorsdatabase.com) before you buy.

Sizing a Standby Generator

Sizing is the most important decision you will make. Too small, and the generator cannot handle the loads you need. Too large, and you pay more upfront and burn more fuel than necessary.

Standby generators are rated in kilowatts (kW). Typical whole-home units range from about 7 kW to 24 kW, and the largest residential units reach roughly 48 kW. Here is how sizes map to real homes:

• 7-10 kW — covers essentials: refrigerator, furnace or boiler, lights, sump pump, and a few outlets.
• 14-18 kW — adds central air conditioning, a well pump, an electric water heater, and most of the home.
• 22-24 kW — powers nearly everything in a large home at the same time.

To size correctly, list the appliances you must run during an outage, add up their running watts, and account for starting surge: motors and compressors draw two to three times their running wattage for a few seconds on startup. Air conditioners and well pumps are the biggest culprits. Add 20 to 30 percent headroom, and have a dealer run a formal load calculation during the quoting process.

Installation and Cost

Expect to pay for more than the generator itself. A professionally installed standby system — unit, transfer switch, concrete pad, fuel connection, electrical work, and permits — typically lands in the low five figures for a typical home, depending on the size of the unit and the complexity of the job. Running a natural gas line a long distance adds cost, and propane setups need a tank, which you can rent or buy.

This is not a DIY project. Most jurisdictions require permits and a licensed electrician, and your utility may need to approve the interconnection. Improper installation is a fire hazard and voids the warranty. Choose a factory-authorized installer — most major brands offer multi-year warranties when the system is installed by an authorized dealer.

Top Standby Generator Brands

The residential standby market is dominated by a handful of established names:

• Generac — the largest residential standby manufacturer in the U.S., with a deep dealer network and a wide range of sizes.
• Briggs & Stratton — a long-standing engine maker with a solid lineup of air-cooled and liquid-cooled home standby units.
• Champion — best known for value and portable power, but also offers home standby models with strong warranties.
• Kohler — a premium reputation and commercial-grade engineering across a wide size range.

All four are well regarded. Brand choice usually comes down to dealer availability, warranty terms, and local service support — a generator is only as good as the technician who services it. Compare rated wattage, fuel type, noise rating, and transfer switch compatibility for any model; GeneratorDatabase lists those specs side by side.

Standby vs Portable: Which Is Right?

If a standby generator feels like more than you need, a portable unit costs a fraction as much and needs no installation, but it must be started manually, fueled from stored gasoline or propane, and run outdoors away from doors and windows. For short, occasional outages, a portable may be the smarter buy; for whole-home automation and multi-day reliability, a standby is hard to beat.

Is a Standby Generator Worth It?

A standby generator is an investment, not an appliance you will use weekly. Whether it pays off depends on how often your area loses power, how disruptive outages are for your household, and your budget. Homeowners who install one consistently cite the same payoff: never waking up to a cold house, never throwing out a fridge full of food, and never worrying about a sump pump during a flood. If you are on the fence, get a load calculation and a quote from a local dealer, then compare candidate models on GeneratorDatabase before you commit.