Whole House Generator Cost: $6,000 to $11,000 by kW Size

How much does a whole house generator cost installed

Installed totals as each publisher reports them. Fixr's figures date from 2022 and run higher than the newer guides.

The guides agree that most jobs land in the high four figures to low five figures, and they disagree on the edges. HomeGuide's average is $6,000 to $11,000 and Forbes Home puts the typical total at about $9,000. Fixr's older 2022 average of about $15,000 is for an 18 kW job. Size, the length of the gas and electrical runs, and whether the transfer switch covers the whole house move a quote from one end to the other.

Do this now: power out and no standby generator yet

1. Portable generator: run it outside only, at least 20 feet from the house, the CPSC says; it counts about 100 deaths a year in the US from portable generator carbon monoxide.
2. Never plug it into a wall outlet to feed the house. A transfer switch or interlock installed by an electrician is the safe way; the generator installation guide prices both.
3. Price the standby after the outage: measure what must run (central air, a well pump, an electric range) so each installer quotes the same size.

Is it an emergency? Buying a generator during an outage

A standby generator is not a same-day job: HomeAdvisor says most installs need two permits at $50 to $200 each, one electrical and one for the fuel line or tank, plus a pad, wiring and a transfer switch. Use a portable safely in the meantime and get quotes when the power is back.

If an existing standby will not run during the outage, that is a repair call; see generator repair.

Whole house generator price by size (kW)

Unit prices only. Each publisher groups sizes differently, so the tiers overlap.

Installation comes on top of these prices. HomeGuide puts labor at $3,000 to $5,000 for a typical job and $5,000 to $12,000 or more for units over 20 kW. Forbes Home's installation range is $1,500 to $5,000. The generator installation guide breaks the labor into its parts.

Generac 22kW generator price

Generac lists its 22 kW Guardian with a 200 amp whole-house transfer switch and Wi-Fi at an MSRP starting at $6,979, unit and switch only, with a 5-year limited warranty. HomeGuide puts the Generac 22 kW unit at about $5,000 on average, and its range for Generac units from 7 to 24 kW is $2,000 to $5,000.

No guide we cite publishes a single installed price for the Generac 22 kW. Expect the installation labor above on top of the unit, and ask each installer to quote the same model so the numbers compare.

Kohler compared

HomeGuide lists Kohler at $2,700 to $16,000 for 6 to 48 kW, with the automatic transfer switch included. Kohler's 24RCLA, an entry liquid-cooled model with a 2.2 liter four-cylinder engine, starts at an MSRP of $17,900 and carries a 5-year warranty. It is liquid-cooled and the Generac 22 kW is air-cooled, so the two prices do not line up one for one. Kohler also makes air-cooled home models.

What size whole house generator do I need

Forbes Home ties 22 to 25 kW units to homes of 3,000 to 5,000 square feet, and Fixr's average job uses an 18 kW unit. Square footage is only a starting point. The size that matters is the load the generator has to carry and start at once: central air, a well pump, an electric range or an EV charger all push it up.

• Whole-house backup. The transfer switch covers the main panel and the generator is sized for everything that may run at the same time.
• Essential circuits. The switch covers a set of circuits (refrigerator, furnace, some lights and outlets), so a smaller unit can do the job.
• Ask for the math. A good installer lists what the quoted size will run and what it will not.

Natural gas or propane: fuel and hookup cost

Standby generators run on natural gas or propane. Fixr's 2022 breakdown prices the gas or propane piping at $1,000 to $1,500, the wiring to the house at $1,000 to $2,000, and the pad at $500 to $1,000. HomeAdvisor says most installs need two permits at $50 to $200 each, one electrical and one for the fuel line or tank. None of the guides cited here publishes a fuel cost per hour of running, so ask the installer for an estimate and check it with your gas utility or propane supplier. When a generator will not start, the fuel supply is one of the first checks; see generator repair.

Other costs that show up on the quote

• Automatic transfer switch: $600 to $2,500 installed (HomeGuide).
• Pad: $150 to $400 pre-cast (HomeGuide), or $50 to $75 per square foot poured, about $1,000 for 18 square feet (HomeAdvisor).
• Wiring: $6 to $8 per foot (HomeGuide).
• Permits: $80 to $450 in total (HomeGuide).
• A bigger electrical service if the panel cannot carry the generator; see panel upgrade cost.

Ongoing costs: maintenance and lifespan

Year-based lifespans. The guides' hour-based figures conflict, so they are left out.

Maintenance is the cost that keeps coming. Angi puts annual service at $150 to $300; HomeGuide's range is wider, $200 to $650. The generator maintenance schedule lists what each visit covers and the repairs that skipped service leads to.

Solar and a battery instead of a generator

A home battery stores power instead of burning fuel. It is a different trade-off from a generator, and this guide's sources do not price the two side by side, so we do not compare them here. Battery prices and what it takes to add one are on adding a battery to existing solar and Tesla Powerwall cost.

For a whole-home picture of repair prices, see home repair costs.