Whole-House Generator Installation Cost

National cost range

Low end

$5,000

Simple access, like-for-like

Typical

$12,000

What most jobs come in at

High end

$22,000

Upgrades, difficult access, code work

What you are actually paying for

Find the row that matches your situation. Quotes that differ wildly from each other usually differ in scope, not in price.

What moves the price

In descending order of impact. These are also the questions worth asking a contractor whose quote sits outside the range above.

1. 1

   Generator capacity

   A 10 to 14 kW unit covers essentials. A 22 to 24 kW unit runs most of a 2,000 square foot home including HVAC. Each step up in kW adds $1,500 to $3,000 in equipment cost.

2. 2

   Transfer switch type

   A whole-house transfer switch replaces the main panel interface and costs more than a critical-circuits subpanel switch. Generac, Kohler, and Cummins bundle switches with their units; third-party switches vary in compatibility.

3. 3

   Fuel source and line work

   Natural gas units need a plumber to extend the gas line — often $500 to $2,000. Propane requires a tank install or upgrade. Diesel is rare in residential.

4. 4

   Pad, conduit, and distance from the house

   Generators must sit on a level pad, typically 5 feet from windows and doors per code and manufacturer requirements. Long conduit runs from the generator to the transfer switch add labor.

5. 5

   Permit and utility coordination

   Electrical and gas permits are both required. The utility may need to verify gas line capacity before approving a large generator on an existing residential line.

Direct answer

Whole-house standby generator installation in 2026 typically costs $5,000 to $22,000 installed nationally, with planning figures near $12,000 for a common air-cooled package. A 16–18 kW natural gas unit often runs $5,500 to $10,000; 22–24 kW whole-house transfer switch configurations $9,000 to $15,000; gas line extension adds $500 to $2,000; propane with a new 250-gallon tank $8,000 to $16,000; liquid-cooled 27–48 kW systems $14,000 to $25,000. Generator kW rating, transfer switch type, fuel plumbing, and conduit distance from pad to panel drive the spread—not brand marketing alone.

What each price band actually buys

Low end

16 kW air-cooled, existing adequate gas line, short conduit, critical-circuits switch on smaller homes.

Typical

22 kW air-cooled Generac or Kohler class unit, whole-house transfer switch, pad, electrical and gas permits.

High end

Liquid-cooled unit, long gas run, propane tank install, meter upgrade, complex HOA or setback compliance.

Labor vs materials

Typical split for this job nationally: roughly 45% labor and 55% materials. Crew size is usually 2–4 technicians (electrician plus gas fitter), across two to four days on site plus utility and inspection appointments.

What this price usually does not include

• Annual maintenance contract unless sold separately
• Propane fuel fill beyond initial tank commissioning
• Landscape restoration after trenching gas or conduit
• Main electrical service upgrade unless required for transfer switch ampacity
• Sound attenuation landscaping or custom enclosures beyond manufacturer pad
• Portable generator interlock as an alternative to standby—different scope

Hidden costs that show up on real jobs

Regional variation

Install pricing follows licensed gas and electrical labor markets: Northeast and Gulf Coast storm belts see steady demand; rural propane markets add tank costs urban bids omit. Check `/home/cost/whole-house-generator/[metro]` when localized data is live. Confirm gas utility capacity before signing—utility delay can idle a paid generator on the pad.

Code upgrades this job can trigger

• Automatic transfer switch inspected for utility disconnect before backfeed
• Generator setback from windows and doors per manufacturer and fuel code
• Bonding and grounding electrode integration with existing service
• Gas piping pressure test and electrical permit closeout
• Carbon monoxide and combustion air clearances on enclosed installations

Repair vs replace

Replace an aging standby unit when the engine fails compression tests, the controller is obsolete, or repair exceeds 40–50% of a new installed system with expired warranty. Repair annual maintenance items—battery, oil, spark plugs—on young units. Portable generators with manual cords are not a repair alternative to a failed transfer switch; improper interlocks are life-safety hazards for lineworkers. Size replacement with a load calculation, not square footage rules of thumb.

Timeline and visits

Equipment lead time is often two to six weeks for popular 22 kW models. Site work—pad, gas, conduit—may take two to four days. Utility gas availability checks add calendar time. Final electrical inspection and startup exercise complete the job; plan one outage window for transfer switch cutover.

Quote checklist — line items a fair bid should show

1. Generator kW rating, fuel type, and brand model number
2. Transfer switch type: whole-house versus managed loads
3. Gas line scope, plumber of record, and pressure test
4. Pad, conduit length, and setback compliance
5. Electrical and gas permit fees
6. Startup, owner training, and first maintenance interval
7. Warranty: equipment, labor, and transfer switch
8. Propane tank size and ownership if applicable

Questions to ask before you sign

• What load calculation supports this kW size for my HVAC and well pump?
• Has the gas utility confirmed BTU capacity for this generator?
• Who owns the propane tank and what is the lease versus purchase cost?
• How long is power off during transfer switch installation?
• Is annual maintenance included or required to keep warranty valid?
• What happens if inspection fails on bonding or gas test?

Quote red flags for this job

• Manual crossover without listed transfer switch for whole-house backup
• Generator sized only by square footage
• Gas work by unlicensed installer
• No permit for electrical or gas
• Quote excludes gas line with “TBD” on a natural gas home
• Requires full payment before utility gas approval

Payment schedule norms

Authorized dealers often take 25–40% deposit at order, progress at delivery, balance at startup and inspection. Retain final payment until transfer switch function is demonstrated and permits close.

Seasonality

Demand spikes before hurricane season and after major grid events; spring scheduling is often easier in northern states before summer storm season.

Can you do it yourself?

When this cannot wait

• Medical equipment in the home that cannot tolerate an outage
• Repeated multi-day outages from storms or grid failures
• A sump pump or well pump that failed during a recent outage causing flooding or loss of water

Common questions