How much does a whole house generator cost?

A whole house generator usually costs $7,000 to $15,000 installed in 2026. The generator and its transfer switch run roughly $4,000 to $8,000 for a typical home, and the electrician, gas hookup, pad, and permit make up the rest. Prices here are 2025 to 2026 figures. Your local labor rates, the distance from the gas meter, and your permit office will move the total, so treat every number below as a range to compare against real quotes.

What you pay for the generator itself

Home standby generators are sold by kilowatt (kW) rating. The bigger the number, the more circuits it can carry at once, and the higher the price. The table uses prices from two large online dealers, for units sold with and without the transfer switch that moves your house from utility power to the generator.

These are the prices Norwall and AP Electric showed in October 2026; for Generac they matched to the dollar. Generac’s 10 kW comes with a 16-circuit 100 amp switch, and the larger units and the Kohlers with a 200 amp switch. Prices move with sales, so check more than one seller. A unit sold without a switch costs about $600 to $1,050 less, but you still need a transfer switch to run a house.

Generac’s air-cooled line runs from 10 kW up to 28 kW. Past that, homes with very large loads move to liquid-cooled units, which are bigger and cost more.

What the install adds

The unit is only part of the bill. HomeGuide puts install labor at $3,000 to $5,000 on average, and PowerOutage.us gives the same $3,000 to $5,000. Longer runs and bigger systems push that higher. A typical job includes:

• A transfer switch. If your generator did not come with one, expect $500 to $2,500 for the switch and its install.
• Electrical work. An electrician mounts the switch, runs the wiring, and ties it into your panel.
• A pad. The generator sits on a concrete or composite pad outside, set back from the house by the distance your local rules and the manual call for.
• Fuel connection. Natural gas needs a line from your meter or house piping, at about $20 to $25 a foot. Gas piping is a job for a licensed pro and may need its own permit.
• Permits and inspection, about $100 to $450 depending on your town.

Plan on a permit and a licensed electrician for any generator that connects to your house wiring. NEC 702.5 calls for a transfer switch or interlock so the generator never feeds power back out to the utility line. That backfeed can hurt line workers, and it is the main reason this job is not a weekend project.

Two guides that count the whole job give $6,000 to $11,000 (HomeGuide, December 2025) and $7,000 to $15,000 (PowerOutage.us). Large units, long trenches, and complicated panels push some jobs above those ranges.

Natural gas or propane

Natural gas uses the pipe already at your house, so there is no tank to buy. If you have no gas service, the line from the street may take a utility visit and extra cost. Propane needs a tank and a delivery contract. Tank prices vary a lot with size, so have the tank quoted with the job.

Output changes with fuel too. Generac’s spec sheet rates its 22 kW Guardian at 22,000 watts on propane and 19,500 watts on natural gas. The Kohler 20 kW rates 20 kW on propane and 18 kW on natural gas. Read the rating for the fuel you will actually burn when you check the unit against your loads.

Running and maintenance costs

At half load, the makers publish these fuel figures:

Do the math with your own price. The EIA reports the 2025 U.S. average residential natural gas price at $15.34 per thousand cubic feet. At that price, 160 to 230 cubic feet an hour costs about $2.50 to $3.50 an hour. EIA’s weekly survey put U.S. residential propane at about $2.60 a gallon in early October 2026, so 2.2 to 2.5 gallons an hour costs about $5.70 to $6.60 an hour. Full load burns more: the Generac sheet lists up to 327 cubic feet or 3.9 gallons an hour. Your own bill tells you the real rate. The electricity cost calculator helps you compare that against your grid price per kilowatt-hour.

Maintenance is the other running cost. HomeGuide’s and Bob Vila’s yearly maintenance ranges overlap at about $200 to $300 for a dealer visit with an inspection plus oil and filter. Ask your installer which visits your unit needs. The unit also runs a short self-test on its own, weekly to monthly as you set it, which burns a small amount of fuel.

How sizing changes the price

Going from 14 kW to 22 kW adds about $1,400 to the price, and the install gets pricier as the gas line, wire, and breaker all grow with the unit. Buying more than you need costs money twice: once on the generator and again on the install.

Generac says a 2,000 square foot home typically needs 20 to 22 kW for whole-home coverage, and that the size should follow your peak load, not your square footage. A home that leaves the air conditioner and electric dryer off the generator can often use a smaller unit. The only way to know is to add up your loads first. Use the generator size calculator to find the running and starting watts your list needs, then shop at that kW.

Amps help you read a quote. Generac rates its 22 kW Guardian at 91.7 amps at 240 volts on propane, which is 22,000 watts divided by 240 volts; the watts to amps calculator gives the same 91.7 A. Kohler lists 84 amps for its 20 kW. Both makers fit a 100 amp line breaker at the factory, and both units are sold with a 200 amp transfer switch. The wire from the generator to the switch follows the maker’s installation manual, and your licensed electrician sizes it.

A fair way to compare quotes

Ask each installer to price the same generator model and itemize the transfer switch, pad, gas work, electrical labor, and permit. A quote that lumps everything in one number is hard to compare. Ask whether the price covers the first-year service visit and startup testing. Prices that are far above $15,000 usually come from long trenches, panel upgrades, or a very large unit. If a quote lands well below the ranges above, check that it includes the switch, pad, gas work, and permit.