Standby Generators: An Essential Guide

For most households, everything stops when utility power fails. The lights go off, the central air system goes off, and the freezer and refrigerator go off too. Even the computer, laundry appliances, and TV become useless.

Standby Generators

The worst part is that power outages have become even more common in recent years. Intense storms (58%), snow/ice storms (13.8%), and high winds (13.5%) are the three leading causes, followed by hurricanes/storms and planned outages.

It’s very concerning considering the high cost of power outages. For example, if the power outage leads to frozen pipes in your home, it can cost you up to $10,000 to fix the damage. The cost is even higher if the frozen pipes burst, resulting in basement water damage. Fixing basement water damage costs $26,807 on average in the US. We won’t mention the potential cost to restock the fridge.

A standby generator is considered the best solution to power outages and interruptions. It stands guard, ready to provide backup power to your home in case utility power fails.

What’s a Standby Generator?

A standby generator is a backup power solution designed to provide power to homes, businesses, or commercial and industrial applications in a power outage. It’s typically a stationary appliance set on a concrete pad outside the home or facility.

A standby generator can provide power for a few hours during an interruption or several days during extended power outages. They are commonly used for power outages due to inclement weather, disasters (natural or artificial), or regular power outages due to an unreliable power grid.

How it Works

Standby generators are permanently installed with natural gas or propane engines to generate utility-quality power within moments of a power outage. The various components work together to provide electricity to your home (or facility) immediately there’s an outage.

The Main Parts of a Standby Generator

The main components of a standby generator include the engine that powers the unit, the alternator unit, and the control panel.

  • The engine

Engine sizes vary from one unit to the other but ultimately determine the generator’s power output. A larger engine capacity means the unit has the capacity to produce more power to turn the generator, thus more electric power. However, it also means that the unit consumes more fuel per unit of time. Standby generator engines can have between two and eight pistons.

  • The alternator

The alternator is where electricity is made. It produces a very clean electric current with a stable frequency and a non-fluctuating voltage. This is very important as many home appliances and devices, including phones, the TV, and laptops, are susceptible to frequency and voltage fluctuations. Most devices will get damaged within minutes of experiencing fluctuating voltage.

The alternator is also powerful enough to start motors in heating and refrigeration systems and handle fast-changing loads, such as central air conditioners.

  • Microprocessors

Microprocessor controllers within the standby generator perform a myriad of functions. For one, they start the generator and prepare it to take the load. The microcontrollers also run regulation cycles to keep the internal components lubricated and protect the seals.

Additionally, it’s tasked with performing diagnostics and notifying the user of potential issues. For instance, the microcontrollers will notify you when it’s time for service. It does so via text alerts, emails, etc., thanks to advanced technology.

Every generator has a cooling system. However, the cooling mechanisms vary from one generator to the next. The largest standby generators use liquid coolant to keep the systems from becoming too hot and potentially starting a fire.

A pump circulates coolant through the engine to the radiator. Then a powerful fan blows air through the radiator to remove heat from the coolant. After that, the now-cool coolant cycles back through the engine. The process goes on and on to keep the engine and adjacent components cool enough.

How it Works

Standby generators connect directly to the home’s electrical panel. When there’s a blackout, the microcontrollers detect the issue within seconds and prepare the generator to restore power. Then the generator turns on, and your power is restored.

All this can happen within 10 seconds or less, thanks to a unique feature known as the Automatic Transfer Switch (ATS).

The ATS is an electric switch that automatically switches a current load between two sources. It’s a self-acting intelligent power switch governed by a dedicated control logic that allows it to almost instantly transfer (switch) load circuit to another power source.

In standby generators, the automatic transfer switch essentially chooses the home’s power source. If you have power from the grid that meets acceptable standards, the switch selects utility power. However, whenever the utility power becomes inadequate or unavailable, such as during an outage, it switches the power source to the generator.

It’s a slightly more complicated process than explained here. For instance, the generator microcontrollers are usually the first to detect inadequate or unavailable grid power – many seconds before the ATS becomes aware. When this happens, the controllers start the generator engine and give it a few seconds to stabilize. Then the controller signals the ATS to switch the power source to the standby generator.

While switching the power source to the generator, the ATS isolates the home from the main supply to protect anyone working on the grid from electrocution and the generator from harmful overloads.

When power returns, the controller senses that grid power is back and checks to determine that the power is stable. If so, it signals the ATS to transfer the home’s load back to the grid circuit. Then the controllers prepare the generator for shutdown by operating a cooling cycle.

The Automatic Transfer Switch is the feature that facilitates the fast response.

Benefits of a Standby Generator

All types of generators are valuable in scenarios where grid power is unavailable. However, standby generators are even more valuable for the following reasons;

1. They come on automatically

Although some standby generators still use Manual Transfer Switches (MTSs) that require the user to manually turn on the generator whenever there’s an outage, most modern units have an ATS switch that automatically transfers the load to the generator circuitry.

This is beneficial for two reasons. First, it means you don’t have to lift a finger even when the power goes out, as the ATS will swiftly swing into action to start the generator automatically. Secondly, it guarantees that you’ll have power back within 10 seconds or less of an outage.

2. A standby generator can power the entire home

This is the main difference between standby generators and portable generators. Whereas portable generators are designed to power only a few appliances and devices, standby generators can power every item in the home, including the heating system.

You also don’t need to wire multiple standby generators together, like we usually do with portable models. Instead, just one is enough for the entire home.

3. It can run as long as you want

A standby generator can run for days on end without the need to stop. This is made possible by a few things. First, standby generators run on natural gas or have large fuel reservoirs that keep them running for days. This is unlike smaller generators that gave 3-gallon tanks or smaller.

Additionally, standby generators have elaborate cooling and exhaust systems that allow them to run for many hours without overheating or causing gas poisoning risks.

Key Considerations When Shopping for a Standby Generator

If you’re excited by the benefits and wish to invest in a standby generator to remedy the frequent blackouts in your area, we recommend the following considerations;

  • Size (in watts)

The first thing to consider is your power needs. How much power do you need? To find out, you need to list down all electrical appliances and devices in your home and find the total wattage. Then, find out the total starting wattage (for the listed appliances). Now, add the two numbers to determine your total power needs, i.e., the ideal whole-house standby generator for your home.

However, you can also choose to buy a standard home standby generator to only power the essentials during a power outage. Whichever your choice, standby generator sizes typically range from 9,000 kilowatts to over 50,000 kilowatts.

  • Fuel type

The other thing you must carefully consider is the fuel source. As we’ve mentioned repeatedly, standby generators can run on various fossil fuels, including diesel, gas, natural gas, and propane. Which option best suits your needs?

Generally, smaller standby generators, rated under 22kW, are air-cooled units that run on either natural gas or propane. Meanwhile, larger units rated 22kW or higher are liquid-cooled units that can run on natural gas, propane, or diesel. It’s best to discuss your options with a generator professional before making the final decision.

  • Initial cost

Finally, don’t forget about the initial costs. How much do you need upfront to purchase and install the generator? Do you have the budget?

Although prices vary widely depending on a myriad of factors, such as manufacturer, size, and controls, it costs between $900 (for a 5kW unit) and $25,000 (for a 38kW unit) to purchase and install a standby generator. The national average is $15,000 for an 18kW unit, with natural gas models the most expensive. Installations alone cost $5,000 to $6,000, though more complex units can cost up to $11,000 to install.


We didn’t provide the installation guide on purpose – you must never attempt to install a standby generator yourself. Connecting the fuel and electrical lines is a delicate process that’s strictly left to the experts.

Standby Generators: An Essential Guide

Carter Brooks

I'm Carter Brooks, an expert in portable generators with a background in Mechanical Engineering. My experience spans from working in the manufacturing industry, where I gained hands-on knowledge of various machinery, to a focused career in blogging about portable generators. I combine my technical expertise with real-world experience, garnered from numerous camping trips and outdoor adventures, to provide in-depth reviews and practical advice. My blog is dedicated to helping consumers understand and choose the best generators for their needs, emphasizing both efficiency and environmental impact.

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