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How Much Does a Whole House Generator Cost?

Put away the candles and flashlights: A generator can keep your home up and running during the next power outage. A typical whole house generator costs between $5,000 and $25,000, with the average consumer spending $14,520.

Updated Aug 30, 2022 4:33 PM  

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Typical Range: $5,000 to $25,000

National Average: $9,520

When lightning strikes too close to home or the wind picks up and Edison turn the power off AGAIN. The power flickers then goes out, what is your first thought? 


  • The freezer full of food?
    Children who will panic if they wake up without a night-light? 

  • Critical medical equipment? 

  • The HVAC system? 

Power outages are inconvenient no matter how brief they may be, but they can be expensive or even dangerous in some circumstances, especially if the outage is prolonged. A whole house generator protects your family and home by automatically sensing the power loss and triggering a backup power system. The typical cost range for a whole-house generator is $5,000 to $25,000, with homeowners paying $14,520 on average.

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Many people envision a Home Depot generator when they consider backup power options. That gasoline-powered portable block on wheels that generates power (along with a whole lot of noise) is what you’ll see on sale during storm season. A whole house generator is a different kind of appliance. Once limited to hospitals and government buildings, large generators are now an option available to many homeowners. They can be especially popular in areas regularly threatened with heavy snowfall or high winds or in remote areas where the power lines are less reliable. While the average whole house generator cost nationwide is $14,520, several options can raise or lower this cost based on your home’s needs. It’s essential to understand the possibilities and know the terminology before you start shopping so you can develop a realistic budget and decide if a whole house generator is right for you.

Whether you have a small portable gas generator or a massive standby unit, the cautions you’ll need to take when using them are the same. Never, under any circumstances, operate a generator inside your home or garage—even with the doors and windows open. Carbon monoxide is a lethal gas that can accumulate quickly, and by the time you know something is wrong, it may be too late. Portable generators belong outside, with the doors and windows nearby closed tightly. Home generators are safe and beneficial instruments, but care must be taken for proper ventilation and air exchange so you can keep your home warm and bright but also protect the people living in it.


Factors in Calculating Whole House Generator Cost

The demand for whole house generators varies based on weather conditions, market, and region. You’ll see the cost of all generators spike after an extended power outage caused by a snowstorm or hurricane, for example, as people who have been inconvenienced by the outage rush to stores to protect themselves from future events. In addition, there are several variables you’ll find when you begin shopping, and these choices can affect your total cost by thousands of dollars. You’ll want to know the size of your house and electrical panel so you don’t buy more power than you need. Other options may be nonnegotiable.

Generator Type and Size
There are two kinds of generators for a house: fixed and portable. Most generators capable of powering an entire home are fixed: permanently installed on the outside of your home and hardwired into your electrical system. They come in sizes ranging in power from 7 to 38 kilowatts and cost from $8000 to $30,000. To power a 2,500-square-foot home, you’ll want a standby generator with about 25 kilowatts of power. Another option is the portable generator, which can range in power from about 2 to 8 kilowatts. These are less expensive but are limited to powering a couple of lights and appliances—they’re generators that will keep the most basic electrical items running but aren’t backup power for the whole home. These smaller support generators cost between $200 and $10000.

Power Source
Generators operate on a variety of fuel sources. This won’t affect the purchase price but will affect the cost of purchasing and storing the fuel and the total cost of running the generator. You’ll see generators powered by gasoline, liquid propane, diesel fuel, and natural gas. Some solar-powered generators have entered the market, but they’re a bit less common.

Type of Start
Every generator, whether portable or fixed, has a manual start option. In most cases, portable generators have a pull cord similar to a lawn mower starter, but others have an electrical switch. Fixed standby generators, wired into your home’s electrical panel, will sense the power interruption to the house and automatically turn on, ensuring minimal loss of power and potential damage to the home and its systems. These generators also include a manual start switch as a backup.

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Additional Costs and Considerations

Along with installation, the cost of the generator itself is high, but it can save money in the long run by allowing you to remain in your home during a lengthy power cut. After the purchase and installation, however, there are still some costs to account for.

Standby generators automatically run themselves for just a few minutes several times a week. This keeps the engine oiled and running smoothly and allows the generator to run diagnostics and let you know if there’s a problem that needs to be addressed. This doesn’t cost anything—but it does mean that the generator needs to be continuously fueled. You’ll need to schedule occasional maintenance service by a technician periodically, usually just before the season when you’re most likely to need backup power. Expect to pay between $80 and $300 for this yearly service.



The generator itself can’t help you if you don’t have the appropriate fuel on hand. For an installed generator, this usually means connecting the generator to a natural gas line or sizable liquid propane tank. If you’re using a tank, you’ll need to keep the tank filled, and the costs for this will depend on your contract with the gas provider. Portable units need to be filled as they are used because both gasoline and diesel fuel have short shelf lives and will lose effectiveness if left sitting in a tank (and could potentially damage the tank and sensors as well). Price out how much gas you’ll keep on hand and change it out periodically to gauge your cost of use.


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Do I Need a Whole House Generator?

Portable generators are less expensive and take up less space on your property than whole house generators—and they can be loaned to friends and family if they need a power boost. And really, how often do you need to power your whole house for days on end? For many homeowners, a portable generator is a reasonable investment for those rare moments when it’s required. In some circumstances, though, there are clear benefits to choosing a whole house generator.

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Don't start fire season unprepared

A top-rated pro can install a generator for you. Get free, no-commitment estimates from experts near you.

What Size Generator Do I Need?

Generators are labeled by size using the total number of kilowatts they can produce. There’s no sense in purchasing a generator with more power than you need, and choosing one that is significantly underpowered for your needs will be frustrating and feel like a waste of money. The best way to determine the correctly sized generator for a house is to invite an installer to come to your home and assess your property. They can take stock of what you would like the generator to cover and recommend size and type. It’s a good idea to collect several of these estimates. Suppose you’d prefer to estimate yourself, whether to check the accuracy of a contractor’s bid or to choose the size on your own. In that case, you can look at each item you’ll need to be plugged in while using the generator, including appliances, electronics, the water heater, HVAC systems, and the garage door. Each should be marked with a label that shows how many watts the item uses.

Your formula will look like this:

Total number of watts needed/1000 = Number of kilowatts needed to power the home

The number of kilowatts is your guide: If it’s between two sizes of generators, you can choose to size up for comfort or size down if you’re willing to engage in strategic power use during an outage to save a few dollars.


Q. What do I need to know about generator maintenance after the installation?

Generators only operate outdoors, so it’s not surprising that they’ll need a little maintenance periodically. At the cost of between $75 and $300, annual maintenance should keep your generator in excellent condition. A standby generator will monitor and maintain itself by running several times a week and reporting back any potential problems.


Q. How many watts does it take to run a house?

Larger houses will need more watts to fully power than small ones. A 1,000- to 3,000-square- foot home can usually get by on a 16,000-watt (16 kW) generator, while a larger home between 3,000 and 5,000 square feet would need a 20,000-watt (24 kW) generator.


Q. How long does a whole house generator usually last?

A good standby generator should last at least 20 years if well maintained. A heavily used generator will last for a shorter amount of time and should be maintained more frequently to increase its lifespan.


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