What's a Home Standby Generator?
A home standby generator offers a handy solution for permanent power protection. Standby generators produce consistent, stable power that computers and other sensitive electronic equipment can use safely. A home standby generator can run for extended periods using natural gas or liquid propane (LP) as a fuel supply. Most natural gas residential generators operate using the existing natural gas line to your home, making them a popular choice.
In a power outage, a permanently installed standby generator for power outages returns your home or business to power within seconds, even when you’re away. Since the generator is hardwired into the electrical system of your home or business, items connected to the system, such as furnaces, well pumps and lights, operate during a power outage.
How Much Does a Home Generator Cost?
The cost of a home generator includes the cost of the generator itself, the materials necessary for installation and, in some cases, the cost of an automatic transfer switch (ATS). If the ATS doesn’t come with the generator, you need to add the price of an ATS kit. Here are some estimated standby generator price ranges and estimates for ATS kits:
- Prices for a standby home generators vary by the size or running wattage of the generator and the number of circuits it powers, as well as the included features and your location. In general, standby home generators can start in the $3,000 to $4,000 range and run up to $10,000 or more.
- The cost of an ATS kit also varies by capability, features and your location. General prices for an ATS kit can start around $800 and run to $2,000 or more.
Keep in mind, these are general estimates only and prices vary. Consultation with a professional helps you identify the capabilities you need and determine the cost of the generator and other equipment that meets your needs. You also need to factor in the cost of installation in your area.
Don’t install a standby generator or a transfer switch as a do-it-yourself project. These jobs require permits and a licensed electrician. Learn more about our installation services.
Types of Generators for Other Power Needs
While standby units are long-term power solutions for a home, there are other types of generators for sale. These generator types are good portable generators for a variety of specific electricity needs. If you want temporary or mobile power, consider a portable generator. Choosing an inverter generator for your home or for recreation gives you portable power in a lighter and quieter device than a comparable traditional generator. A portable power station or solar generator with solar panels lets you store power from the sun to operate electric devices indoors as well as outdoors. Take a look at our guides for each type of generator to choose the best generator for the home.
Always follow the generator manufacturer's operating, maintenance and safety instructions.
How to Power Your House With a Generator
An automatic standby generator works by constantly monitoring the voltage supply to your home. When there's an interruption in your electricity, the generator detects the problem and starts running to power your house:
- The controller in the generator monitors incoming voltage through the automatic transfer switch.
- When there's a power interruption, the controller waits 10 to 20 seconds and then starts the generator's engine. Within seconds, the generator produces voltage.
- The ATS safely closes the utility line that connects your home to the local power grid while opening a line of power from the generator to your home. This stops any back-feed of power into the neighboring houses.
- Within 10 to 20 seconds, the standby home generator system begins supplying electricity to the circuits you've chosen for generator power. The controller continues to monitor the utility line and switches back to utility power when the power from the grid returns.
- When the controller senses that utility line voltage has returned to a steady rate, it transfers the electrical load back and begins monitoring for another outage.
Automatic Transfer Switches Route Power to Your Home
An automatic standby generator requires an automatic transfer switch or ATS to connect the generator to your existing electrical system. Many automatic standby generators come with an ATS, but you can also purchase an ATS kit separately. Consult your standby generator documentation or talk to a licensed electrician to find the right ATS for your generator and the circuits you want to power.
Although the generator creates the power, the transfer switch is the core of your home generator system. It's a permanent electrical panel near your main circuit breaker panel and allows you to safely connect a generator to your home's electrical circuits. Options include transfer switches that provide power to only essential appliances or those that supply every circuit for complete coverage. Some allow for prioritization of optional circuits, known as load shedding, where essential circuits remain powered and nonessential circuits cycle off if the generator gets overloaded.
Find out more about your home's electrical system and see What's in My Breaker Box?
What Size Generator Do You Need to Run a House?
The generator size you need to power a home depends on the size of the home and the power requirements of the items you need during an outage. Consider both of these factors to find the best generator for your home. Here are a couple of examples:
A 10,000-Running-Watt Generator in a 15,000-sq-ft Home
A generator with a 10,000-running-watt rating connected might be suitable for a 1,500-square-foot house to power:
- A small- to medium-size air conditioning unit
- A furnace
- The kitchen
- A bathroom
- A couple of bedrooms
- A well pump
A 22,000-Running-Watt Generator in a 2,500-sq-ft Home
A 22,000-running-watt generator can supply power to a 2,500-square-foot house to power:
- A large home air conditioning system
- A furnace
- A kitchen
- Three bathrooms
- Five bedrooms
- A home office
- A garage
- A well pump
The examples above are general estimates only. The actual generator size or capability a home needs depends on the power needs of the devices it needs to operate. You also need to consider the number of circuits the generator and ATS can handle.
Generator Coverage Plans
Deciding on a power coverage plan helps you narrow down your home generator choices and find the best generator for your home’s needs. Here are some types of home generator power coverage plans to consider:
- Essential Circuit Coverage: Many homeowners choose to cover only certain circuits when using their generator for power outages rather than trying to power all circuits. Essential circuits might include heating and cooling systems, refrigeration, lights and a well pump. This can be a cost-effective option.
- Managed Whole-House Coverage: With light and medium appliance usage, a smaller generator such as an 11,000-watt or 13,000-watt model and a 200-amp ATS provides coverage by managing how much power appliances can use.
- Complete Whole-House Coverage: When the power goes out, everything comes on and stays on, no matter how many circuits there are. Choose this backup power solution for whole-house protection.
The most accurate way to select the right generator for home use is to have a professional conduct a load measurement of the circuits and items you intend to back up with your generator. An amp meter measures the power required as each appliance starts up. The result of this load measurement gives you the total power requirement for backup power. Learn more about our installation services.
Learn how to make your home energy efficient by reading Create an Energy-Efficient Home.
Air-Cooled vs. Liquid-Cooled Generators
An air-cooled standby generator uses a fan to force air across the engine for cooling. For most homes, air-cooled models provide exceptional value. Depending on the model, one of these generators can power 12 to 16 key circuits during a power outage. A 20,000-watt air-cooled standby generator provides complete protection for many types of homes.
A liquid-cooled generator uses an enclosed radiator system for cooling, similar to an automobile radiator. Higher-wattage generators with larger engines usually require liquid cooling.
Backup Home Generator FAQ
How Do I Size a Generator?
You can size a standby generator by matching the circuits between your home's main electrical panel and the home generator system's load center. An electrician should measure the electrical load of devices you want to power to help identify the circuits to back up and the capability the generator needs.
Can I Use a Standby Generator Instead of a Utility Service?
No, while a home standby generator can provide backup power for an extended period of time during a power outage, it won’t function as your main power source on an ongoing basis.
Can I Install a Home Standby Generator?
No, installing a home standby generator and it’s automatic transfer switch isn’t a DIY project. You might be able to perform some site preparation steps and have a professional make the electrical panel and fuel connections. However, installing a home standby generator and its ATS is a job for a licensed electrician with the necessary training and knowledge of the required permits.
Does a Generator Require Maintenance?
Yes, routine maintenance is necessary to keep a home standby generator running properly. Generators need periodic oil and filter changes to ensure maximum performance for years of reliable service. Refer to the owner's manual for routine maintenance procedures and schedules. Consider having a professional service your generator twice a year.