Whole House Generator Cost

Average DIY
$740 (5kw)
Average Pro
$5,860 (8kw)
Typical Range
$4,200 – $6,450
Low End
$360 (DIY)
High End
$14,500 (Pro)
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Get Free Backup Generator Advice and Installation Cost Quotes

The estimated cost to install a natural gas or propane 10kw – 15kw backup generator with automatic transfer switch is around $7,500. For a 30kw generator, expect to pay $14,000 or more.
Last Updated: Friday, June 14, 2019

The majority of this Costimate focuses on whole house backup power generators. We have however included a low cost estimate for a portable generator that can be used to power limited essentials.

How Much does a Backup Generator Cost?

Low Estimate
$380 – $850
Average Cost Estimate
$4,500 – $6,900
High Estimate
$8,750 – $14,500
Generator Size 3kw – 5kw 7.5kw – 10kw 15kw – 30kw
How Much Will it Power? Essentials Only Essentials & Conveniences Whole House
Automatic Transfer Switch No Yes / No Yes
Fuel Source Gasoline Gasoline / Natural Gas or LP Natural Gas or Propane
Noise Level Loud Loud / Quiet Quiet
Installation Supplies $0 – $150 $150 – $450 $150 – $450
Installed By DIY Pro or Electrician Pro or Electrician
Permit & Inspection $0 $0 – $275 $0 – $275

Sections: Overview | Product Costs | Installation Cost | DIY or Pro | Web Compare | Shared Pricing

whole house generator installed at home

Overview of Backup Power, Whole House Generators

When an electrical outage occurs, everyone wishes they had a backup generator. A small unit can supply power for home essentials like the refrigerator, furnace or small window AC unit and basic lighting for several days, or as long as your gasoline lasts. A large standby generator that runs on natural gas and is wired to power your entire home can produce all the electricity your home needs, so the household won’t miss a beat when the power goes out due to a storm or other electricity interruption. If you’re unsure, Popular Mechanics has a great comparison to decide if a standby generator is right for you.

This Costimate addresses whole house generators an the cost to have a generator installed at your home. The units are also called standby and backup generators, and our comparison above includes a portable generator that can be used to power select items on a temporary basis.  The information here will help you determine what size unit you’ll need, something an electrical contractor can and should do too. Generator installation cost is itemized for the labor and supplies required. Below, you can compare what we’ve discovered about standby generator installation costs with information from other sites and with actual costs submitted by homeowners. Our goal is to assist you in deciding if the backup generator installation cost is worth the benefits– keeping your home inhabitable, comfortable and safe while preventing the loss of perishable food.

Backup Generator Cost Details

Equipment Cost Factors

While the price of the generator is the biggest expense, there are other factors that will determine your total standby generator installation cost. Let’s explore all of them.

  • The size of your home and what you plan to power – In order to provide power to your whole house, generators start at about 6,000 watts (or 6kW) and can be as large as 100,000 watts (100kW) for residential models, though very few homes require a unit larger than 30kW. A general rule is that you need 3-5 watts per square foot for essential electricity and 6-14 watts per square foot for whole-house electricity based on the number of appliances you have with high electrical demand. These include a sump pump, air conditioner, home security system, electric dryer, electric water heater, well pump, jetted tub, sauna, grow lights and a second refrigerator or freezer.
  • Whether the unit has a transfer switch or one must be added – The transfer switch senses the loss of power from the grid and automatically starts the standby generator. In most states, they’re required to connect a generator to your breaker panel.
  • How far from the electrical panel the unit is installed – The further away the generator is from the panel, the more time and materials are required and higher the total generator installation cost will be.
  • Whether a pad is needed – Costs are lowest when the generator is installed on concrete already in place, such as a patio. Costs go up for a DIY pad ($) or pad installed by a contractor ($$). Some homeowners want the generator installed in a garage since there is already a concrete floor and the unit will be out of the weather and safe from thieves. A few building inspectors permit indoor installation in a garage or outbuilding, but that is not recommended, even with vented exhaust. Since deadly carbon monoxide is a byproduct of natural gas and propane combustion, outdoor installation is the safe choice. Generator manufacturers recommend installation at least six feet from any window or other opening such as a dryer vent or furnace air intake.
  • A larger propane tank and/or extra propane (Optional) – If you use propane, a tank with 500-gallon capacity or more should be installed. Many propane sellers supply the tank free to customers, though minimum propane purchases apply. Plan to keep the tank nearly full (80% capacity is the maximum allowed) to have fuel necessary for a lengthy power outage. Most suppliers offer plans to regularly top off your tank, often with a price break since the propane is delivered as drivers make their rounds rather than making a trip out for one customer.
  • Anti-theft equipment (Optional)– Some homeowners in high-crime areas install a cage around their generator that is anchored to the concrete slab. This option doesn’t pose the health risk of installing the unit in a garage.

If you decide to use a smaller generator for essentials, Honda has a great informational page about using smaller units to power your home during power outages.

Cost of Accessories & Installation Supplies

  • $1,875 – $4,900 | Generators up to 15kW (Total power for homes to approx. 2,500 sq. ft. / essential power for homes to 5,000 sq. ft.)
  • $3,500 – $12,500 | Generators from 15kW to 30kW (Total power for homes to approx. 5,000 sq. ft. / essential power for homes larger than 5,000 sq. ft.)
  • $9,700 – $24,000 | Generators larger than 30kW (Total power for homes larger than 5,000 sq. ft.)
  • $285 – $650 | Transfer switch, if not included with the generator
  • $40 – $300 | Concrete pad installed DIY or by a handyman
  • $650 – $1,750 | Refurbished propane tanks, 320-1,000 gallons (optional)
  • $1,000 – $2,500 | New propane tanks, 320-1,000 gallons (optional)
  • $1.85 – $3.00 per gallon | Current cost range of propane
  • $350 – $650 | Security cage for your generator and hardware (optional)

Permits, Inspection, and Related Costs

Permits and Inspection Cost

  • $150-$275 | Average costs for a permit to install a whole house generator and have it inspected to ensure it is properly and safely wired

Time to Install a Home Backup Power Generator

  • Up to 1 Hour | Planning the installation
  • 3-5 hours | Installation of a gas line
  • 6-10 Hours | Installation and wiring of the generator

Electrician Labor Costs

Whole house generator installation costs for electrical contractors range from $60-$100 per hour to wire the generator to the electrical panel plus the cost of wire and additional supplies. A gas line must also be installed, a job usually subcontracted to a plumber at similar hourly rates.

  • $1,800-$3,200 | Backup generation installation cost

DIY or Hire a Prosteve-hansen

If all you need is a small portable 5kw generator to run the refrigerator, freezer, a few lights and power outlets, and possibly a gas furnace or small window ac unit, run extension cords or have an electrician setup your panel as needed, and call it a day.

If you want a whole house generator that can power 90-100% of your home on natural gas or propane, call a pro from the start. They’ll know which size is right for you, as well as handle the wiring of the automatic crossover switch and other electrical requirements to power your home properly.

We have a portable 5kw stored in the garage and use it regularly during storms and power outages as needed. I use the extension cord method since its the easiest due to the location of my breaker boxes. I spoke to an electrician a few months ago and he said he’d charge around $650, to install and wire a manual transfer switch that I can plug into outside, and turn off specific breakers to power only my essentials as needed.

Installing a Whole House Backup Power Generator is for the Pro’s. What do You Think?

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Get Free Backup Generator Advice and Installation Cost Quotes

Get Free Backup Generator Advice and Installation Cost Quotes

Installed Costs from Around the Web

Compare whole house generator installation costs from around the web.

Average
Cost Range
Costimates $5,500 $450 – $14,500
HomeAdvisor $3,565 $400 – $9,200
Fixr.com $6,750 $2,500 – $15,000
Sims HVAC $7,500 $5,000 – $10,000
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Costs Submitted by Homeowners and Pro’s

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