How Much Does a Whole-House Generator Cost?

Highlights

• A whole-house generator has a typical cost range of $1,524 to $8,658 and a national average cost of $5,090.

• The main factors that can influence the total cost include the type and size of the generator, the power source, the type of start, and the cost of labor and permits.

• A homeowner might need to install a whole-house generator if they run a business from home, experience frequent extreme weather, or have a sump pump or crucial electric medical devices.

• A handy homeowner may be able to install a small generator by themselves, but for a large standby generator they’ll typically want to have a professional install the system.

Power outages are inconvenient no matter how brief they are, but they can be expensive or even dangerous in some circumstances, especially if the outage is prolonged. According to Kyle Raabe, executive vice president of consumer power at Generac Power Systems, a generator manufacturer, “During an outage, a home standby generator can help power critical medical devices, maintain access to Wi-Fi and cellular networks, and keep residents safe and comfortable during severe weather.” The best home generators protect families and their homes by automatically sensing the power loss and triggering a backup power system. According to Angi and HomeAdvisor, the typical cost of a whole-home generator is $1,524 to $8,658, with homeowners paying around $5,090 on average.

While the best portable generators work for emergency use during storms or time spent in a camper, a whole-house generator is a different kind of appliance. They are able to support major systems such as electrical and HVAC in the event that the home loses power. Home generators are safe and beneficial instruments, but as with portable generators, it’s vital to ensure proper ventilation and air exchange in order to keep a home warm and bright while also protecting the people living in it. Homeowners will want to familiarize themselves with common generator features and terminology before shopping in order to develop a realistic budget and decide which whole-house generator is the best fit for them.

Factors in Calculating Whole-House Generator Cost

The demand for generators for whole-house use varies based on weather conditions, market, and region. Homeowners will want to note the size of their house and electrical panel so they don’t buy more power than is necessary.

Generator Type

For those wondering, “How much does a generator cost?” the answer depends on the type of generator. Home backup generators may be standby, manual, or portable, and costs can vary greatly.

There are many uses for portable generators. Costing about $500 to $2,000 on average, they can support one or more important systems such as air conditioning in the event of a power outage. However, they are not powerful enough to support an entire home.

Partial and whole-house generators (also called standby generators) are larger, permanent installations that sit outside of the home and are hardwired into the electrical system. According to Raabe, standby generators are particularly convenient because they “turn on automatically during a power outage event by using a transfer switch wired into the home’s electrical system, meaning homeowners don’t have to deal with fueling and starting a portable generator as well as running electrical cords from the generator into a home.”

Partial generators run from $2,000 to $6,300, and most whole-house generators cost between $5,000 and $18,000. Whole-house generator installation costs are the highest because this type of generator can power an entire home.

Generator Size

One of the most crucial parts of choosing a generator is ensuring that the unit will provide sufficient power. Standby generators come in sizes ranging in power from 9 to 48 kilowatts (kW) and cost from $500 to $18,000. One of the best standby generators with about 20 to 24 kW can power most of a home’s appliances and costs $5,000 to $6,500. Another option is the portable generator, which can range in power from about 1 to 7.5 kW. These are less expensive but are limited to powering a couple of lights and appliances—they will keep the most basic electrical items running but won’t power the whole home. These smaller home generators cost between $500 and $2,000. Some common generator sizes and their average costs are below.

Generator Brand

Whether homeowners are browsing Home Depot generators or shopping online, there is a wide variety of brands to choose from. Size options, as well as prices, may vary between these brands, so homeowners will want to find the unit that best fits their needs and budget. Below are the starting costs for some of the best generator brands on the market.

Fuel 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. Generators can be 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.

Photo: bobvila.com

Start Type

Every generator, whether portable or standby, has a manual start option. Most portable generators have a pull cord, but others have an electrical switch. These manual generators typically cost between $500 and $2,000. Fixed standby generators, wired into the home’s electrical panel, will sense the power interruption to the house and automatically turn on, ensuring minimal loss of power and limited potential damage to the home and its systems. Generators with this added convenience come at a higher price point of $2,000 to $30,000. Automatic generators also include a manual start switch as a backup.

Concrete Pad Installation

Before going ahead with the whole-home generator installation, homeowners will want to remember that the unit will need a permanent resting spot. The most common installation method is on a poured concrete pad, which offers reduced vibration and increased airflow and prevents pooling water from damaging or rusting the underside of the unit. The pad needs to be strong, solid, and level. Professional installation will run between $50 to $75 per square foot, including site preparation and concrete pouring.

Labor

A contractor may itemize the whole-house generator installation costs, including the charges for site preparation, labor, fuel storage tank, upgrades to the electrical panel, and any additional materials. Some contractors may have a flat rate for the entire installation. In these cases, it’s essential for a homeowner to fully understand what the installation includes. On average, installation cost ranges from $1,500 to $5,000.

Transfer Switch Installation

For a standby generator that will power an entire home, an electrician will need to install a transfer switch, which connects the generator to the circuit board in the home and allows it to run power through existing circuits. These take close to 4 hours to install (around $1,200 in labor costs), and the switches can be manual or automated.

Permits

An installed generator hooks into a home’s electrical system, so a permit is required to ensure that the work is done correctly and safely. In addition, most municipalities will require a permit to pour a concrete pad to support the generator. These permits average between $50 and $200 apiece.

Photo: depositphotos.com

Additional Costs and Considerations

Along with the cost of installation, the cost of a whole-house generator itself is high, but buying a generator for a house can save money in the long run by allowing homeowners to remain in their homes during a lengthy power cut. After the purchase and installation, however, there are still some costs for homeowners to keep in mind.

Maintenance and Running Costs

Standby generators automatically run for just a few minutes several times a week to keep the engine oiled and allow the generator to run diagnostics. This means that the generator needs to be continuously fueled. According to Raabe, “Generators should be serviced by a certified dealer. Maintenance is recommended every 200 hours of runtime or 2 years, whichever comes first, and typically includes an inspection of the unit as well as an oil and filter change.”

Generator service costs between $80 and $300 per visit. It’s also a good idea to invest in one of the best generator covers to protect the unit from the elements and extend its lifetime. “It’s a smart idea to test your generator periodically, especially when upcoming weather conditions suggest an outage might be imminent, and as long as the homeowner uses the proper safety procedures when doing so,” Raabe adds.

The generator itself can’t do its job without the appropriate fuel, usually diesel, propane, or natural gas. The daily cost to run a 21 kW generator on natural gas is about $90. Running a 20 kW unit on propane for a day costs about $220. Using diesel for a generator of the same size costs $175 per day on average. Portable units need to be filled as they are used; both gasoline and diesel fuel have short shelf lives and will lose effectiveness if left sitting in a tank. Homeowners will want to price out how much gas to keep on hand and change the tank out periodically to gauge the cost of use.

Enhancements and Improvements

Several potential upgrades will make a generator more efficient. A wireless monitor provides access to the status of the generator. If the homeowner is away and there’s a power outage, they can make sure that the generator has kicked on. These monitors cost between $200 and $400. A smart load manager can help create different zones in the home and switch the power between them. This option can make an undersize (and less expensive) generator work in a larger house and costs approximately $150 to $300.

Electrical Upgrades

An electrical subpanel redirects power from a home’s main panel to another part of the property. This can prevent the main panel from overloading. If a home does not already have a subpanel, or it has one that is older than 25 years, an electrician may recommend adding a new subpanel before installing a generator. This can cost between $530 and $2,000. In other cases, a dedicated circuit may need to be installed before the generator. This may be the case if the home’s electrical panel is not easily accessible from the generator’s location. It costs about $500 to $1,000 to put in a dedicated circuit.

Battery Backup Installation

Battery backup is one power source option for standby generators. These units draw power either from the home’s panel or from a solar source to be stored until it is needed. These units can cost $10,000 to $25,000, plus an additional $800 to $1,500 for installation.

Whole-House Generator Cost by Type of Fuel

The type of fuel a generator uses affects the total cost in two ways. First, the price of the unit itself is affected by the fuel type. Second, the cost of running the generator will vary based on the cost of that particular fuel at the time that the generator is needed.

Diesel 

Costing between $3,000 and $20,000, diesel generators are usually larger machines that can power a whole house. Exceptionally efficient, diesel-powered generators are more cost-effective the larger they get.

Gasoline 

Gasoline generators are usually the least expensive option. They are simple engines that use gasoline to produce electricity. Gasoline is readily available in most parts of the country, making this a popular choice. However, it’s important for homeowners to note that gasoline has a short lifespan and may need to be discarded at a cost when it has gotten too old. Gas-powered generators are smaller, less powerful options that are portable and require a manual start. A diesel house generator costs between $500 and $3,000.

Liquid Propane 

Clean-burning liquid propane (LP) can be stored indefinitely if it’s stored properly. It can be a great option for homeowners who already have a liquid propane contract and a large tank to use with other appliances, such as a dryer or stove. An LP generator can be a small portable generator or a larger standby unit and cost between $2,000 and $21,000. Homeowners who don’t already have a large tank or a contractor will need to store many smaller gas cans to make sure they have power when they need it. At that point, LP generators are not as cost effective as other models.

Natural Gas 

Generators powered by natural gas are more expensive at the time of purchase than gasoline generators, averaging between $2,000 and $21,000; however, there’s little fuel waste because the generator uses fuel drawn directly from the utility when it needs it. Homeowners are advised to keep in mind that while natural gas prices are often a bit lower than gasoline, a natural gas generator uses more gas than other types.

Solar 

Solar generators are also modestly sized portable generators simply because the technology needed to convert and store large amounts of power would require too much space. The best solar generators are sustainable and not dependent on petroleum-based fuel, which is a significant environmental benefit but may be limited in power generation by the stormy weather that caused the outage to begin with. This technology is still in development and will likely become more efficient and streamlined as technology advances. A solar generator for the home will cost between $2,000 and $25,000, with most costing at least $10,000.

Do I need a whole-house generator?

Portable generators are less expensive and take up less space on a property than whole-house generators—and they can be loaned to friends and family if they need a power boost. In some circumstances, though, there are clear benefits to choosing a whole-home generator instead.

Home Business

One of the most unexpected benefits of a standby generator is that for those who work or run a business from home, one of these units can make the difference between a deal made and a deal lost. Without a generator, an ill-timed thunderstorm can cut off connectivity moments before a big meeting or client consultation. While relying on a portable means one will need to quickly get outside to fuel and start up the unit, a standby will switch on automatically.

Extreme Weather Conditions 

While many areas that live under the threat of extreme weather have moved toward underground power lines, most of the country’s power grid transmission is still dependent on wires strung carefully between poles. For homeowners who live in an area that regularly loses power due to weather conditions, a whole-house generator can provide great peace of mind.

Sump Pump

Sump pumps are an automated way to keep basements and low-lying areas of the home from accumulating water or flooding—at least if they have power. When the storm bringing a flood to the basement has also knocked out the power, a sump pump can’t help, and there is likely to be water damage in the basement and potentially structural damage to the home. A standby generator that will make sure the sump pump can do its job.

Crucial Electric Medical Devices

Homeowners who have breathing machines, respirators, home dialysis machines, or other power-assist devices in their homes know that power loss is a matter of life and death. Immediate power is essential for medical devices to continue working. A whole-house generator, even a smaller one that only powers the medical devices, is crucial in this case.

Photo: depositphotos.com

What size whole-house generator do I need?

So what size generator do you need? “One of the first things to think about when choosing the correct generator for your needs is the size of your home and the amount of energy you typically consume,” says Raabe. “It’s also important to consider what you want powered during an outage—the whole home or a select number of critical loads.” A 14 to 18 kW unit is often sufficient for powering essential functions in a small or medium-size home. A 26 to 32 kW unit is a big enough generator for a whole home with average energy needs. Larger homes that require a lot of power may need a 45 to 48 kW generator. The best way to determine the correct whole-house generator sizing is for an installer to assess the home and the property. It’s a good idea to collect several of these estimates.

Some homeowners prefer to estimate the costs themselves, whether to check the accuracy of a contractor’s bid or to choose the size on their own. Homeowners taking this approach will need to look at each item that will need to be plugged in while the generator is in use, including appliances, electronics, the water heater, HVAC systems, and the garage door. They will then need to mark each one with a label that shows how many watts the item uses.

The formula will look like this:

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

For example, if a homeowner knows that it takes about 7,500 watts to power their home’s most essential appliances and systems, then they’ll want a 7.5 kW generator. The number of kilowatts is the guide: If it’s between two sizes of generators, homeowners may want to size up for comfort or size down and engage in strategic power use during an outage to save a few dollars.

Whole-House Generator Installation: DIY vs. Hiring a Professional 

If a portable generator is adequate, most homeowners can prepare the generator before an anticipated outage or get it running pretty quickly after an unanticipated one. However, a larger standby or backup generator is not a DIY installation.

According to Raabe, “The process of installing a home standby typically involves a mix of electrical, plumbing and site preparation work, as well as obtaining necessary permits.” For starters, there are many regulations concerning where the generator may be located in relation to the home, other structures such as garages, and neighboring properties. Permits must be obtained before work can start, and the power provider will need to be notified.

Homeowners will also need to make note of local requirements for gas connections. Additionally, generators are large and heavy and must sit on a concrete pad. They require advanced electrical work and possibly fuel line installation.

Homeowners will want to remember that these units are complex and that making mistakes with a home generator can result in electrical shock or carbon monoxide exposure. Pouring the pad incorrectly, installing the connections improperly, or even pulling the wrong permits can be dangerous and costly, so the best option is to hire a professional to make sure the installation is completed smoothly.

How to Save Money on Whole-House Generator Cost

Saving money on a generator purchase is primarily a matter of being patient, considering the timing, and knowing exactly what is needed. While simply finding one of the best cheap home generators is an option, homeowners don’t necessarily have to forgo desired features to stay within budget.

• Shop around for estimates. Collect several estimates, both on the size of the generator and the installation cost.

• Use fewer contractors. Choose a contractor who can perform all the needed tasks (concrete pouring, gas plumbing, and electrical) to save on subcontractor fees.

• Plan installation in the offseason. An off time of year may be the best time to buy a generator since power losses are less frequent and demand is lower.

• Plan ahead. Don’t run out and buy a generator right after the first big storm, when the item, material, and labor costs are highest.

• Take on some of the prep work. Ask if there’s any work you can do ahead of time, such as preparing the site or pulling the permits yourself.

• Buy the right size generator. Make sure that you don’t need to size up or down before you buy.

Photo:istockphoto.com

Questions to Ask About Whole-House Generator Installation

It’s important for a homeowner to ask a potential contractor some questions before hiring them. As always, homeowners will want to ask about licensing and insurance (and the licensing and insurance of any subcontractors or workers who are expected to take part in the project). It’s also a good idea to ask for and check references. The following are some additional questions specific to generator installations that homeowners can ask about whole-home generator costs.

• What unexpected costs might crop up during the installation?

• Which parts of the job will you handle, and which will you subcontract?

• What is the payment schedule?

• Why do you think this generator is the correct size for my home? Should I consider going up or down a size?

• How much will it cost to run the generator?

• How long can the unit continuously run?

• Why is this the best site for my generator?

• What maintenance do you expect I’ll need? Do you provide maintenance through a contract or individual appointments?

• How long will the unit last until it needs to be replaced?

• After installation, will you show me how to use the generator properly?

FAQs

Decisions about size, type, fuel, and other elements will help homeowners determine what the best whole-home generator option is for their home. These can start to feel like too many choices, so just ahead are a few of the questions that are most often asked about this topic, along with answers for getting started.

Q. How much does it cost to run a whole-house generator? 

This depends on the size of the home, the size of the generator, and the number of items that need to be powered. On average, a 21 kW natural gas generator costs about $90 per day to run, while propane and diesel units of the same size cost $220 and $175 per day, respectively.

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 $80 to $300, annual maintenance will keep a 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 (20 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 will need to be maintained more frequently to increase its lifespan.

Sources: HomeAdvisor, Fixr, Angi