What is Average Installation Cost of a Whole House Generator?

Getting the right sized whole house generator for your home is one thing and getting it installed in the right way and at the right price is totally another thing. Some companies do include generator installation as a package deal, but they charge you too much for the complete package. Therefore, it is better to be aware of all the factors contributing to the total installation cost.

In this article, we will be covering the different aspects of whole house generator installation. To give you an idea of the lump sum cost, it is sufficient to say that the average range varies from $10,000 to $20,000. It includes the generator, delivery costs(if any), equipment cost, and contractor’s fee. The main variant in this range is the generator itself. Hence, we will discuss the average costs of various types of generators as well and from different brands as well.

Let’s walk you through the cost estimation process of whole house generator installation.

Whole House Generator Installation Average Cost

A whole house generator installation cost may start somewhere around $1000 (only installation or a 4-5kW portable generator) and may go up to $25,000-$30,000 (generator and installation). The average cost rests around the bracket of $15,000-$16,000 for a 2000-3000 sq. ft. home with a 16-20kW generator.

Whole House Generator Cost Average
National Average $15,000-$16,000
Average Range $10,000-$20,000
Minimum Cost $1,000
Maximum Cost $30,000

Whole House Generator Cost by Type

You can use standby or a portable generator as your whole house generator. However, it has become a custom to tag standby generators as whole house generators. Standby and portable generators come in various shapes and sizes, and both have the same purpose. They provide you with instant electric power during an outage. However, they are quite different in terms of operation, maintenance, installation, and cost.

Whole House Generator Cost by Type

A portable generator may cost you under $500, but you can’t use it for whole-house purposes. Portable generators above $1500 can be treated as whole house units because they usually supply you with more than 5,000 watts of power. A standby generator’s cost starts from $2,000 and can go up to $25,000 depending on the features and power generation capacity. The whole house generator prices also vary according to the power output. Holistically speaking, a generator larger than 5,000 watts can be treated as a standby unit for small homes, condos, and apartments with 2-3 people living in it. With increases in your house area and the number of inhabitants, the power requirements also increase. A larger home needs more power compared to a small home. Let’s check the prices of generators according to their size in the table below.

Generator Size and Average Cost
Generator Size Average Cost
5-6kW $700-$2,000
7-12kW $1,000-$4,000
13-15kW $1,500-$4,500
16-19kW $5,000-$7,000
20-22kW $5,500-$8,000
22kW-25kW $6,000-$9,000
25-kW-30KW $9,000-$12,000
30kW-38kW $10,000-$22,000

What is pertinent to highlight here is that no single factor alone can decide how much you will be paying for a complete installation. Hence, it is important to look at other factors explained below.

Which Size Generator is best for your home?

To find out which generator is best and enough for your needs, you need to do a couple of things. First of all, you need to calculate the total power you want from a generator. Some people want to power only the essentials during an outage. They can navigate a power outage with a small portable unit. On the contrary, a lot of people wish to run everything during an outage. For them, a standby unit is best. To calculate your power needs, you need to list all the appliances you need to run on a generator.

Second, you need to find out the starting and running wattages for each appliance. The starting wattage is needed to start the appliance, and the running wattage keeps it going. Motorized appliances have a higher starting wattage than running wattage. Therefore, you need to account for this while selecting the generator size.

Starting portable generator

You can calculate this by checking the user manuals of each appliance or search online. If you plan to buy a whole house standby generator, you will need to find out your total power requirement and add some additional watts to adjust the extra load. Some companies also offer a free assessment of your power needs and tell you how much power you need. We have given an example below of a medium to a large household with 5-6 people living.

Appliances Starting Wattage Running Wattage
Refrigerator (2) 2400 400
1 HP Furnace 4700 1750
TV (2) 600 600
Lights 600 600
AC (2) 3600 2400
1/2 HP Well Pump 2000 900
1/2 HP Sump Pump 2000 900
Total 15900 7550

Please note that the information given above is best for a 15kW generator. You can expand or reduce the list as per your needs.

Fuel Type and Whole House Generator Price

A whole house generator can be run on gasoline, diesel, propane, or natural gas. The selection of the fuel type depends on different factors such as availability and cost of the fuel. The most common fuels for standby generators are natural gas, propane, and diesel. The reason is that they have a long shelf life. Propane and natural gas burn cleaner than gasoline/diesel and are therefore preferred for longer runtimes.

Fuel type is important while discussing the average installation cost of a whole house generator because the unit prices may vary accordingly. There is not a major difference, but you need to keep this in mind as well.

Whole House Generator Cost and Starting Mechanism

Almost all of the standby units come with an automatic starting mechanism. They have sensors installed in them which turn on the unit within 1-2 seconds of a power outage. All you notice is a maximum 5 seconds blackout, and every appliance in your home is up and running. Some old models may come with a key starting mechanism. These models are a bit cheaper than the automatic ones. Expect to pay $800-$1,500 more for an automatic starting standby generator.

Brand Wise Whole House Generator Cost

Standby generators’ cost also varies from one brand to another. Some leading brands like Kohler, Generac, and Cummins charge you more than Chinese brands. It doesn’t mean that Chinese generators are not worth it. Some Chinese companies produce high-quality and durable models. The reason behind low prices is economies of scale. When production is done at the mass level, production costs and other variable costs are reduced. Hence, they can sell at lower prices.

The price range for Kohler may vary from $3,000-$12,000, for Cummins, $4,000 to $16,000, and for Generac, the price rag for whole-house generators is $2,000-$20,000. Their models are usually priced according to the size and features of the unit. If you are going for a large generator with all the latest features, you may have to pay up to $20,000 for the generator alone.

Whole House Generator Installation Cost

Once you have finalized the generator, the next step is installation. A typical installation can cost you somewhere around $4,000-$5,000. The installation process consists of 4 main steps: ground pad, piping installation, wiring, and transfer-switch installation.

For pad installation, the cost can be around $600-$1,000. You can also do a DIY installation and save a few bucks. The generator pad is usually made of concrete or gravel. It is best to install your generator under a shade. The piping installation will be around $1,000-$1,500, and the wiring charges will be $1,000-$2,000. The transfer switch installation cost will be $1,500-$3,000. All these components play a very important part in how your generator will perform.

An imbalanced pad may not let the generator perform effectively and may also cause noise issues. Faulty wirings can lead to line losses and fluctuations. The piping installation refers to connecting a standby generator to your home’s natural gas or propane tank. Once the installation is complete, you need to make sure that there are no leaks in it. A transfer switch is responsible for converting the electrical supply to your home for utility power to the backup generator. It also ensures that there is no overlapping between both electricity sources.

Permit Costs

Some states require you to obtain a permit for installing a whole house generator. The permit is usually granted after an inspection. When you apply for a permit, an inspection team will visit your premises before installation and check the intended installation place, its proximity to your home, and to that of neighbors. Once everything is fine, they will give you conditional permission to install the generator.

After the installation is complete, the inspection team will visit again. This time they will check the electric wiring, plumbing, transfer switch, generator pad, and how much noise your machine is making. The inspection team may suggest some improvements. However, if they are satisfied, the installation will be approved, and you will have your permit after some days.

The permit costs vary from $100 to $300. If you don’t obtain permits and install the generator, you may face legal action and will have to pay hefty fines.

What’s the best place for Installing a Whole House Generator Cost?

The ideal location for installing the generator is near your home’s circuit panel. If you install the generator far away, the wiring cost will sky-rocket. It is installed outside your home near the circuit panel. You also have to keep in mind the natural gas connection. Installation experts will take care of all these things. Regardless of the installation place, you must make sure that there is a canopy on top of the generator so that rainwater, snow, or intense sunlight cannot harm your machine.

How to Select the Best Generator Installer

The quality of installation plays an important part in deciding the performance and total life of your machine. Therefore be vigilant while selecting the installer. Follow the checklist below to ensure that you are hiring the right people for the job.

running whole house generator after installation

  • Check the permit/license of the generator installation team.
  • Make sure they are aware of the local laws for generator installation.
  • Select certified electricians and plumbers for making electrical/gas connections. Your home’s safety depends on it. So be careful here, please.
  • Don’t settle with only one quote. Get price estimates from at least 3 contractors.
  • Check each contractor for their previous work history and ask for references in the neighborhood.
  • Look for companies that are insured, bonded, and have a good reputation in their work.
  • Don’t go for the lowest quote as such companies may compromise on quality.
  • It is better to ask for itemized billing to have an idea about the quality of materials used and how much you will be paying for each item.
  • Ensure that your state approves all the materials and equipment used in the installation process.
  • Don’t make huge payments upfront. Divide the work into goals and then pay accordingly.
  • Be smart. Try to bargain a little but don’t compromise on the quality.

Standby Generators Maintenance Cost

The maintenance cost of a standby generator depends on several factors like the size of the generator, running hours, and fuel type. Some companies offer free maintenance and oil change for the first time as well.


What is the average cost for installing a whole-house generator?

The average cost of installing a whole house generator is $15,000-$16,000 for a 2000-3000 sq. ft. home with a 16-20kW generator.

How long a whole house generator last?

A whole house generator usually lasts for 15-20 years. However, to make it last for such a long time, you need to take care of it and follow a strict maintenance routine.

Can portable generators be treated like whole house units?

Larger portable generators can be treated as whole house units. However, they produce limited power and may not be too reliable compared to standby units.

What is the estimated cost of a whole house generator for a 2,000 sq. ft. house?

The generator can cost you between $3500 and $7500. With installation, the total cost can go up to $10,000-$20,000.

Final Words

Now that you know everything about the whole house generator installation cost, I am sure the installation companies won’t mint extra money from you. The installation costs can be summarized into four things: the generator, brand, features, and installation process. If you know how to size your generator, you won’t spend extra money on buying a huge generator. For brands and features, don’t compromise by saving a few bucks. A low-quality machine’s maintenance and operational costs are way too high than a technologically advanced and fuel-efficient machine. For the last component of the installation cost, we have given details guidelines above.

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