Ashburn, VA

How Much Does A Generator Cost To Install?

$3,000 – $5,000 Installation Only
$6,000 – $11,000 Whole-House Generator + Install

Home generator installation costs $6,000 to $11,000 on average, including the whole-house generator. Standby backup generators cost $2,000 to $6,000 alone, and portable generators cost $500 to $2,500. The cost to install a generator transfer switch is $400 to $2,000.

Get free estimates from generator installers near you or view our cost guide below.

Reviewed on September 9, 2020, by Tom Grupa and 5 Expert Generator Installers on HomeGuide.

Whole House Generator Cost

Whole house generators cost $6,000 to $11,000 on average, including installation. Home generators cost $3,000 to $6,000 alone, and the cost to install a whole-house generator is $3,000 to $5,000. Generac generators cost $2,000 to $5,000 for a whole-house unit, without installation.

Whole House Generator Cost - Chart

Whole House Generator Cost
Item Average Cost
Whole House Generator $3,000 – $6,000
Installation $3,000 – $5,000
Total Cost To Install $6,000 – $11,000

*A complex installation costs $5,000 to $12,000+. Learn more

Home Generator Cost By Size

Standby generators can power select circuits or a whole home, depending on the generator's size in kilowatts (kW) and circuits in the transfer switch.

Generator Cost By Size - Chart

Generator Cost
Size Price Range Typical Coverage
2 – 5 kW $250 – $1,400 One appliance and a few lights.
7 – 10 kW $2,000 – $3,000 10 lights, refrigerator, sump pump, well pump, microwave, TV, laptop, coffee maker, and furnace fan.
13 – 16 kW $3,000 – $4,500 Full home under 1,500 square feet.
17 – 20 kW $4,000 – $6,000 Full 1,500 to 3,000 square foot home.
22 – 25 kW $4,500 – $12,000 Full 3,000 to 5,000 square foot home.
30 – 48 kW $10,000 – $16,000 Large luxury home or commercial applications.

*Not including installation.

  • Home standby generators, also called backup or whole-house generators, are permanently wired into the electric panel and automatically turn on during a power outage.
  • Whole-home generators cost $50 to $150 per day to run and provide a power source for up to 500 hours continuously or three weeks.
  • Standby generators last 15 to 30 years or 10,000 to 30,000 hours.
  • Portable generators cost $500 to $2,500 for a 5 to 10 kW unit, must be turned on manually, and can only power critical appliances and ten lights.

Average Cost To Install A Generator

Average Cost To Install A Generator - Chart

Average Cost To Install a Generator
National Average Cost $8,500
Minimum Cost $3,000
Maximum Cost $22,000
Average Range $6,000 to $11,000

*Prices for a 13 to 22 kW backup generator plus installation.

Generator Costs By Type

Generator prices range from $2,000 to $6,000 for a 7 to 22 kW natural gas or liquid propane system, without installation. Whole house diesel generators cost $5,000 to $18,000. Portable gasoline generators cost $500 to $2,500 for a 3 to 10 kW backup unit.

Backup Generator Prices
Fuel Type Portable Standby
Gasoline $250 – $4,500 --
Natural Gas $900 – $4,300 $2,000 – $6,000
Liquid Propane $250 – $4,000 $2,000 – $6,000
Diesel $3,300 – $6,700 $5,000 – $18,000
Solar $500 – $3,300 --

*Prices for units with power capacity of 2 to 24 kW. Not including installation.

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Gasoline Generator Cost

Portable gasoline generators cost $500 to $2,500 for a 3 to 10 kW unit. Gasoline generators have lower upfront costs and can power essential appliances during brief outages. However, they are noisy and require storage space for the generator and gas, which has a shorter shelf-life than other fuels.

Always run a gasoline generator outdoors at least 20 feet from the home to prevent carbon monoxide poisoning.

Natural Gas Generator Cost

Natural gas generators cost $2,000 to $6,000 for a whole house, depending on size. They can be installed to a home’s existing gas line and require no fuel storage. Natural gas is cheaper than diesel or propane, but relies on pipelines that may be shut off or damaged during severe storms.

20 kW Whole House Generator With Natural Gas Installation

Liquid Propane Generator Cost

Liquid propane generators cost $250 to $4,000 for portable models or $2,000 to $6,000 for permanent backup units, depending on size. Liquid propane lasts longer and burns cleaner than other fuels but is more expensive and requires a large storage tank, which increases installation costs.

Diesel Generator Cost

Portable diesel generators cost $3,300 to $6,700 and whole-house diesel generators cost $5,000 to $18,000. Diesel generators are more efficient, reliable, and require less upkeep than natural gas or propane generators. However, they cost more, require manual refueling, and emit pollutants.

Solar Generator Cost

Portable solar generators cost $500 to $3,300 and are ideal for apartment and condo residents or homeowners seeking an environmentally friendly solution. Solar generators run quietly, produce no fumes, and can be used indoors, but can’t store enough energy to power a whole home.

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Generac Generator Costs

Generac generators cost $2,000 to $5,000 for a 7 to 24 kW whole-house unit, plus $3,000 to $5,000 for installation. Generac’s standby generators turn on automatically during power outages and run on natural gas or liquid propane. Generac is the leading brand in whole-home generators.

Generac Generator Cost - Chart

Generac Generator Prices
Power Capacity Average Price
7 kW $2,000
10 kW $3,000
16 kW $3,800
17 kW $4,000
20 kW $4,500
22 kW $5,000
30+ kW $12,000

*Prices not including installation.

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Other standby generator brands to compare are Kohler, Briggs & Stratton, Honda, and Cummins.

Kohler Generator Cost

A Kohler generator costs $2,700 to $16,000 depending on size, ranging from 6 to 48 kW. Kohler home generators run on natural gas or liquid propane, feature remote smartphone monitoring, and include an automatic transfer switch to turn on automatically during power outages.

Briggs & Stratton Generator Cost

Briggs & Stratton home generators cost $2,400 to $15,300 depending on size, with models ranging from 10 to 48 kW. Briggs & Stratton generators feature wireless monitoring, automatic low oil shutdown, and power management to control power distribution to select appliances and prevent overloads.

Cummins Generator Cost

Cummins standby generators cost $3,100 to $13,900 for models ranging from 13 to 40 kW. Cummins generators feature sound-insulated enclosures, remote diagnostics, and intelligent load management to balance power use across multiple appliances so a smaller generator can power an entire home.

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Generator Installation Costs

Home generator installation costs $3,000 to $5,000 on average, not including the backup generator itself. The cost to install a whole house generator depends on the size, fuel source, distance from the electrical panel and gas meter, and amount of wiring and gas plumbing to hook up.

Generator Installation Cost - Chart

Cost To Install Whole House Generator
Type Average Cost
Typical Installation $3,000 – $5,000
Complex Installs (Longer Distances or > 20 kW) $5,000 – $12,000+

*Not including generator.

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Standby Generator Installation Cost Factors

Complex generator installation jobs may require long trenches for electrical conduit and gas pipes, propane tank installation, or higher labor costs to install liquid-cooled generators.

Standby Generator Installation Cost
Factor Average Cost
Home Energy Assessment Free With Installation
Labor Charges For Electrician $40 – $100 per hour
Transfer Switch Installation $400 – $2,000
Electrical Wiring $6 – $8 per foot
Gas Line Installation $12 – $25 per foot
Concrete Pad $150 – $400
Propane Tank Installation $400 – $1,800
Permits $80 – $450

Standby Generator Installation in Home Backyard

  • Electricians charge $40 to $100 per hour to install wiring and hook up a backup generator to the electrical panel.
  • Natural gas and liquid propane generator installations require gas plumbing by a licensed professional. Gas line installation costs $12 to $25 per linear foot.
  • Installing a liquid propane generator typically costs more than a natural gas or diesel generator because it requires a new fuel tank. Propane tanks cost $400 to $1,800 on average.
  • Separate electrical, plumbing, and mechanical permits may be required depending on local regulations. Permits cost $80 to $450 total on average.
  • A pre-cast concrete pad costs $150 to $400 for a generator, which is typically three to four inches thick.

Generator Transfer Switch Installation Cost

The average cost to install a generator transfer switch is $400 to $2,000 for materials and labor. For labor alone, and electrician costs $200 to $500 and takes three to four hours to install a transfer switch. A manual or automatic transfer switch connects a generator to a home's electrical panel.

Cost To Install Generator Transfer Switch - Chart

Cost To Install Generator Transfer Switch
Type Average Total Cost
Manual $400 – $1,300
Automatic $600 – $2,000

*Transfer switch plus installation.

  • Manual transfer switches are ideal for portable generators, but the switch must be flipped manually when the power goes out.
  • Automatic transfer switches are optimal for standby generators and automatically turn on a generator during a power outage.

Generator Transfer Switch Prices

A manual transfer switch costs $200 to $800 on average, and an automatic switch costs $400 to $2,000. Prices depend on the amperage and don't include installation.

Generator Transfer Switch Cost
Amps Manual Automatic
30 Amp $150 – $500 --
100 Amp $200 – $700 $350 – $1,000
200 Amp $450 – $1,000 $700 – $1,450
400 Amp -- $1,650 – $2,700

*Transfer switch only. Installation labor adds $200 to $500.

The transfer switch amps must match the main breaker in the electrical panel. Otherwise, transfer switches that only power select circuits should be sized by an electrician according to the power requirements.

Generator Interlock Installation Cost

A generator interlock installation costs $400 to $850 on average for the interlock kit, power box, breaker, cords, and electricians labor. An interlock kit allows a portable generator to connect to the electrical panel without a transfer switch and eliminates a dangerous direct connection.

Generator Interlock Installation Cost
Item Average Cost
Interlock Kit $50 – $150
Breaker, Power Box, Cords, Misc. $200 – $400
Electricians Labor $150 – $300
Total Cost To Install $400 – $850

An interlock covers the panel's main cutoff switch so it can't switch on while the backup generator is running. Not all interlocks meet local building codes or work with every electrical system.

Potential Installation Drawbacks

  • For safety, a generator should be located outside at least five feet away from doors, windows, vents, and flammable material.
  • Most generators produce 60 to 70 decibels (dB) from 25 feet away, similar to a central air conditioner. Some city properties are tighter, increasing the noise level, which may be regulated by local noise ordinances.
  • Generators need regular maintenance to ensure reliability.

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Portable Generator Costs

Portable generators cost $250 to $2,500, depending on the brand, power capacity, and fuel type. Portable generators under 2 kW cost $250 to $700 and can power one appliance and a few lights, while 5 to 10 kW generators cost $600 to $2,500 and can power multiple appliances and 10+ lights.

Portable Generator Cost - Chart

Portable Generator Sizes and Prices
Watts Price Range
Less than 2,000 $250 – $700
2,000 to 4,900 $300 – $1,400
5,000 to 9,900 $600 – $2,500
10,000+ $1,500 – $5,000

Portable generators are a budget-friendly temporary solution for backup power.

Never plug a generator directly into an outlet in the home. This is illegal and can cause electrocution or set fire to the house.

Gasoline Powered Portable Generator At Home

Portable Generator Installation Cost

The average cost to install a portable generator is $400 to $1,300. A manual transfer switch costs $200 to $800, plus $200 to $500 for the electrical work. Heavy-duty extensions cords rated for 30 to 50 amps cost $30 to $200 for plugging appliances directly into the generator instead.

Portable Generator Installation Cost
Factor Average Cost
Manual Transfer Switch $200 – $800
Electrical Work $200 – $500
Total Cost To Install $400 – $1,300
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Consider these accessories when installing a portable generator:

Portable Generator Accessories
Accessories Price Range Description
Heavy-Duty Extension Cord $30 – $200 Plug major appliances directly into a portable generator.
Wheel Kit $30 – $300 Make it easier to move a heavy generator.
Generator Cover $20 – $165 Protect a portable generator from the elements when outdoors.

Portable vs. Standby Generators

Standby generators are permanently installed outside the home, start automatically when the power goes out, and run for several weeks. Portable generators are smaller and cheaper, but are less powerful, must be started and refueled manually, and shouldn’t run for more than two consecutive days.

Portable vs. Standby Generator Cost - Chart

Portable vs. Standby Generators
Factor Portable Standby
Generator Cost $500 – $2,500 $2,000 – $6,000
Lifespan 2,000 – 5,000 hours 10,000 – 30,000 hours
Power Output 2 – 10 kW 7 – 22 kW
Fuel Cost $30 – $70 per day $50 – $150 per day
Fuel Needs 12 – 20 gallons of gasoline or diesel per day 20 – 75 gallons of liquid propane or 3,000 to 8,000 cubic feet of natural gas daily
  • Smaller and less expensive
  • Lower installation costs
  • Can power lights and essential appliances
  • Prevents food from spoiling during an outage
  • Easy to move around
  • Require minimal maintenance
  • Useful for camping, outdoor events, or construction site
  • Can power a whole house
  • Quieter than a portable generator
  • Can run for days or weeks continuously
  • Starts automatically
  • Can power sensitive electronics
  • Can power heating, air conditioning, and hot water heater
  • Noisy
  • Significantly less powerful
  • Require manual start and refueling
  • Produces hazardous fumes
  • Requires space for storage
  • Can’t power sensitive electronics
  • Can’t power heating or air conditioning
  • Can’t run for more than two consecutive days
  • More expensive
  • Requires professional installation
  • Permanently fixed in place
  • Requires regular maintenance
  • Requires propane or diesel fuel delivery or access to a natural gas pipeline

Generator Rental Cost

Renting a small portable generator costs $40 to $110 per day without fuel, depending on the power capacity and local rental rates. Renting an industrial towable generator costs $300 to $1,000 per week, depending on the size.

Cost To Rent Portable Generator
Power Capacity Rental Price Per Day
1 – 2.5 kW $40 – $55
3 – 4 kW $50 – $65
5 – 7 kW $70 – $90
8 – 10 kW $80 – $110
100 – 300 kW Towable $300 – $500 per week
500+ kW Towable $700 – $1,100 per week

Can Portable Generators Run A House?

Portable generators connect to a home's electrical panel with a transfer switch or interlock kit. This allows the generator to power lights and essential appliances for outages lasting less than two days. However, portable generators can’t power heating and cooling systems or sensitive electronics.

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Home Generator Cost Factors

Total installation costs depend on the generator's size (kW), whether it's standby vs. portable, fuel source, accessories, and the wiring and hook up complexity.

Professional installers offer free home energy assessments to determine the proper size backup generator depending on your power needs.

What Size Generator Do I Need?

Use the watt usage chart for generators below to calculate the size required for a house. In general:

  • Large 20 kW standby generators power a whole house.
  • Mid-range 10 to 16 kW generators power major appliances, including central air conditioning, or an entire home if paired with a smart load manager.
  • Portable 5 to 10 kW generators power multiple appliances and ten lights.
  • A 4 kW generator powers an RV.
Generator Size Calculator For House
Type of Load Wattage Generator Size
7 kW 20 kW 48 kW
Two Lighting Circuits 200 W    
Four Lighting Circuits 400 W    
10 Lighting Circuits 1000 W    
Refrigerator / Freezer 1200 W
Sump Pump 1000 W
Well Pump 1000 W
Furnace Fan 500 W
Garage Door Opener 850 W
Microwave Oven 1000 W
Electric Oven 2000 W  
Radio 150 W
Television 300 W  
Laptop 50 W  
Desktop Computer 200 W  
4-Ton Central Air Conditioner 8500 W  
Washing Machine 1200 W  
Electric Clothes Dryer 3000 W    
Coffee Maker 900 W  
Gaming Console 100 W    
Jacuzzi Bathtub 1500 W    
Hot Tub 6000 W    
EV Charging Station 7200 W    

*Running wattage is shown. Some appliances startup wattage can be double the running wattage.

Home Generator Accessories & Prices

Homes in the northern half of the U.S. need a cold-weather kit for $130 to $500 to ensure the generator turns on when temperatures drop below freezing. A smart load manager costs $130 to $250 and allows smaller generators to power a whole home by balancing the load across multiple appliances.

Generator Accessories
Accessory Price Description
Generator Battery $70 – $300 Starts the generator when the electricity goes out.
Cold-Weather Kit $130 – $500 Ensures the generator starts in regions where temperatures drop below freezing.
Wireless Monitor $200 – $210 Provides access to generator status from inside the home.
Smart Load Manager $130 – $250 Allows smaller generators to power more appliances by balancing the electric load.
Fascia Kit $65 – $130 Protects the generator’s base from rodents and insects.

Generator Maintenance Kits

Generators require regular maintenance with periodic oil and filter changes to ensure maximum performance and reliability. DIY preventative maintenance kits cost $20 to $110. Annual generator maintenance contracts cost $200 to $650 per year and include a full inspection and oil and filter changes.

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How Much Do Generators Cost To Run?

A small 7 kW portable generator costs $30 to $70 per day to run, while a larger 15 to 20 kW whole-home generator costs $50 to $150 per day to run all day. Costs depend on the generator’s size, fuel type, and local gasoline, propane, diesel, or natural gas prices.

Generator Cost To Run Per Day

Daily Generator Running Cost Calculation
Fuel Source Generator Size
7 kW 15 kW 20 kW
Natural Gas $10 – $20 $22 – $32 $30 – $40
Liquid Propane $60 – $70 $145 – $165 $150 – $170
Diesel $32 – $40 $90 – $110 $100 – $120
Gasoline $55 – $70 -- --

*Costs depend on current and local fuel prices.

How Long Can A Generator Run Continuously?

Manufacturers recommend running a standby generator for up to 500 hours continuously, or about three weeks. Most portable generators run for 8 to 14 hours with a ½ power load and one tank of fuel. Portable generators should not run for more than 24 hours continuously without a break.

Time A Generator Can Run
Type Continuous Hours
Portable 8 – 14
Standby Up to 500

Generator Fuel Consumption

A standard 5-kilowatt portable generator consumes 0.75 gallons per hour or 18 gallons per day, which costs about $40 per day. Whole-house 15 to 20 kW standby generators consume 1.22 to 1.60 gallons of diesel per hour or 3.16 to 3.45 gallons of liquid propane per hour.

Generator Fuel Consumption
Fuel Type Generator Size
5 – 7 kW 15 kW 20 kW
Gasoline 0.75 GPH -- --
Liquid Propane 1.42 GPH 3.16 GPH 3.45 GPH
Natural Gas 118 CfH 133 CfH 330 CfH
Diesel 0.60 GPH 1.22 GPH 1.60 GPH

  • Gallons Per Hour (GPH)
  • Cubic Feet Per Hour (CfH)

How Long Do Generators Last?

A standby generator lasts 15 to 30 years and provides 10,000 to 30,000 hours of use with proper maintenance. Portable generators last up to 10 years and provide 2,000 to 5,000 hours of power. Reputable brands offer 5- to 10-year limited warranties on whole house generators.

How Long Do Generators Last?
Type Lifespan In Years Hours of Runtime
Portable Up to 10 2,000 – 5,000
Standby 15 – 30 10,000 – 30,000
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DIY Home Generator Installation

Installing a permanent backup generator involves complex electrical work and gas plumbing that needs a licensed professional for safety. Improper wiring can damage the generator, fry appliances, and endanger utility workers by back-feeding the grid.

Portable generators don’t always require professional installation, and appliances can be plugged directly into the generator. To power more appliances, hire an electrician to install a manual transfer switch to connect the generator directly to the home’s electric panel.

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Hiring A Generator Installer

A professional pulls permits, determines the power and size generator needed to run the house, pours a concrete pad, installs the wiring and plumbing, and safely connects it to the utility grid. Follow these steps to find the best pro for the job:

  • Get at least three in-person estimates to compare.
  • Look for electricians with experience installing home generators.
  • For natural gas and propane generators, select a pro who is certified for gas plumbing.
  • Read reviews and check out their previous work on HomeGuide, Google, and the Better Business Bureau (BBB).
  • Select companies that are insured, bonded, and have been in business for longer than five years.
  • Avoid selecting the lowest quote as quality may suffer.
  • Ask for a written contract and warranty.
  • Get a full breakdown of all costs involved.
  • Avoid making large payments upfront. Come up with a payment schedule for the work completed.

Questions To Ask A Generator Installer

  • How long have you been installing generators?
  • How many generators have you installed?
  • Will your company handle the gas plumbing, or do you use subcontractors?
  • Can you provide references of past work?
  • Are you licensed, bonded, and insured?
  • What costs might be associated with the installation?
  • What permits do I need, and will you obtain them?
  • What is your payment schedule?

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