Real Cost of a Whole-House Generator (2026)

A whole-house standby generator is a $3,000 to $6,000 machine bolted into a $12,000 to $18,000 project. The machine is the half of the bill the product page shows you. The other half is a concrete pad, gas line sizing, a possible gas meter upgrade, an automatic transfer switch, an electrician, a plumber, and permits, and nobody leads with that number.

That is the number you actually need before you take a dealer quote. We don't sell generators. We save you from buying the wrong one, and the fastest way to get burned is to price the machine and forget everything bolted to it. This guide prices the whole project, standby and portable.

If you already know you want standby and just need a shortlist, jump to the best home standby generators. If you are not sure standby is even the right lane, read standby vs portable first, because that one decision moves your budget more than the brand does.

Quick Answer: What a Whole-House Generator Actually Costs

Setup	Machine sticker	Install work	Real all-in
Whole-house standby (22kW-24kW)	$3,000-$6,000	$9,000-$12,000	$12,000-$18,000
Portable + interlock kit	$700-$2,500	$400-$850	$1,100-$3,350
Portable + manual transfer switch	$700-$2,500	up to $1,500	$1,200-$4,000
Home battery (short outages)	$10,000-$30,000 installed	included	$10,000-$30,000

Generac is the category leader in US home standby, and it names Kohler (now Rehlko), Briggs & Stratton, Honda and Champion among its residential competitors in its own annual report. Treat the "70 percent market share" line you will see quoted everywhere with care: it comes from Generac's 2010 IPO prospectus, where the company called it its own estimate "based primarily on internally generated data," and Generac has not published a share figure in an SEC filing since 2012. The machine sits at $3,000 to $6,000 for a common 22kW to 24kW unit, but the number on your final invoice is $12,000 to $18,000 once the install is done. That all-in figure is the one that matters.

The Machine Is Half the Project

Here is where the other half of the money goes, in the order these items usually land on the quote.

Concrete pad and site prep, about $1,000

A standby sits on a stable, level base, usually a poured concrete pad or a composite pad on gravel. Budget around $1,000. A flat yard near the meter and panel keeps this the cheap line. Sloped ground, poor drainage, or a long trench through roots and rock to a spot across the property is where it climbs.

Gas line sizing and a possible meter upgrade, $1,000 to $3,000+

This is the line that surprises people most. A 22kW to 24kW generator is a large gas appliance, and it has to get enough fuel without starving your furnace and water heater. Often the existing line is too small, so a plumber sizes and runs a new one, $1,000 to $3,000 or more depending on distance and pipe diameter. Sometimes the utility also has to upgrade your meter to deliver the volume, a separate cost on its own schedule. If you already have a large-diameter line and a high-capacity meter close by, you dodge most of this.

Automatic transfer switch and electrical, $2,000 to $5,000

The automatic transfer switch is what makes a standby a standby. It senses the outage, disconnects you from the grid, starts the generator, and switches the house over, with you touching nothing. The switch plus the electrician's labor runs $2,000 to $5,000, depending on whether you get a whole-house switch or a managed load center and how far the runs are.

Do not cut corners here, because the transfer switch is also the safety device that keeps your generator from backfeeding the grid and hurting a lineman. If you want the whole house covered automatically, this cost is the point of buying standby, and worth every dollar for that buyer. If you only need a few circuits kept alive, a portable with an interlock does the same job for far less, the interlock vs transfer switch question.

Permits, inspections, and sometimes a panel upgrade

Permits and inspections run a few hundred dollars and are not optional. A permitted install protects your insurance claim and your resale. Older homes sometimes also need a panel upgrade to handle the transfer switch and modern load, another $1,000 to $3,000. A recent panel with open capacity skips this cleanly. A 100-amp panel from the 1980s with no open slots does not, so plan for it now instead of finding it on a change order.

One thing worth separating on the quote: the government's fee and the installer's fee for handling the paperwork are two different numbers, and the second is usually the larger one. Across the eleven jurisdictions our state pages have read fee schedules for, the government's own charge runs from roughly $40 to $90 in Houston to a flat $500 in Baton Rouge, with $75 in Wake County, $80 in Cobb County and Savannah, $128 minimum in Raleigh, $130 in New York City and $227.90 in Miami-Dade. The installer's permit preparation and inspection coordination fee is commonly several hundred dollars on top. Ask for both, separately. The full table with each jurisdiction's own fee schedule is on what a standby generator quote must include.

The four rows most quotes leave out entirely

The line items above are the ones that show up and then move. These four often never appear at all, and each one is real work somebody has to be paid for.

Line item	What it is	Why it matters
Freight and delivery	Getting a 450 to 590 pound machine to your property	No manufacturer or dealer association publishes a standard residential figure, so it has to be asked for by name
Panel load calculation	The calculation that sizes the system to your actual house	Generac's own installer documentation points at NEC 702.4(B)(2), which requires the optional standby load calculation to follow Article 220. It is engineering work, not a guess from square footage
Startup and commissioning	An authorized dealer's first-start visit	Generac's 5-year limited warranty states that coverage begins upon successful start-up and activation. Skip this and the warranty never starts running
First scheduled service	The break-in service	Generac's owner's manual calls for the engine oil and filter to be changed, and the valve clearance checked, after the first 25 hours of operation. On a unit that only runs a weekly self-test, that arrives sooner than owners expect

None of the four has a published national price, so we are not going to print one. What matters is that they appear on the quote as named rows with a number next to each, rather than being discovered later.

Brochure Number vs Real Number

What the product page shows	What the project actually costs
$3,000 to $6,000 machine	$12,000 to $18,000 installed
One clean "starting at" sticker	Pad, gas line, meter, transfer switch, permits, two trades
A number that does not move	A quote that moves with change orders

Here is a realistic worked example, built from the line items above. The numbers are illustrative, but the shape is exactly how these quotes drift.

Line item	First quote	Final invoice
Generator (22kW machine)	$4,900	$4,900
Concrete pad and site prep	$900	$1,100
Transfer switch + electrical	$2,600	$3,200
Gas line	$700	$2,900
Gas meter upgrade	not quoted	$1,800
Permits and inspections	$300	$500
Panel upgrade	not quoted	$1,600
Total	$9,400	~$16,000

The $9,400 quote was not dishonest. It assumed a short gas run, a big-enough meter, and a panel with room to spare. The site visit found a long run to an undersized line, a meter the utility had to upgrade, and a full panel. Three change orders later, the $9,400 job is a $16,000 job. This is why the only standby price worth trusting is the one after a real site survey, and why you get two or three quotes before you sign.

Before you compare bids, check them against what a standby generator quote must include. It carries all 16 line items with the ones commonly omitted marked, the permit fee eleven jurisdictions actually publish, and the manufacturer's own gas-pipe sizing table, which is the row that moved most in the example above.

What Ownership Costs After the Install

The install is not the last check you write. A standby runs a weekly self-test that burns a little fuel and makes noise, usually a few minutes on a schedule you set. Service contracts run $200 to $400 a year, and you replace the starting battery every two to three years and change the oil on a schedule. None of it is dramatic, but it belongs in your budget from day one. The full breakdown is in generator maintenance cost.

The Portable Lane Is a Different Answer

Not every outage pattern needs $16,000 of standby. If you lose power twice a year for six hours, a portable does the job for a fraction of the price, and it is the smarter buy for that homeowner.

A quality portable runs $700 to $2,500. The part people skip is the legal, safe connection. An interlock kit runs $400 to $850 installed and powers your panel through a single inlet, or a manual transfer switch runs up to $1,500. Without one, you are running cords through a window or, far worse, backfeeding your panel, which can kill a lineman and start a fire. Budget the connection as part of the purchase.

A portable also carries a discipline the spec sheet never mentions: it runs outside, at least 20 feet from the house, with the exhaust pointed away from every door, window, and vent, every time. CPSC's published figure is that more than 80 consumers die each year of carbon monoxide poisoning caused by portable generators, and its May 2026 estimates put the 2020 to 2022 average at 98 a year. The deaths cluster in the days after a storm. That rule sells nothing and is not negotiable. Read never run a generator indoors before your first outage.

How to Budget by Your Outage Pattern

Lose power for days at a time? You are the standby buyer. Budget the full $12,000 to $18,000 installed, get two or three quotes after a site survey, and read what size generator do I need so you buy enough capacity without overpaying for a unit you never load.

Lose power for a few hours a few times a year? You are the portable buyer, all-in around $1,100 to $3,350 with an interlock. You trade automatic switchover and whole-house coverage for a machine that costs a tenth as much and still covers your real outage pattern. That is the smart buy, not a compromise.

Short outages with tight noise rules and no gas line? A home battery may beat both on silence, indoor safety, and zero fuel. It loses on multi-day outages, where a generator wins. We say that plainly on both sites. Weigh it in generator vs home battery and cross-check at homebattery.guide.

Permit fees, licensing rules, and even the reference storm that justifies standby differ by state. We break down the real installed number, and the local paperwork that shapes it, in state guides for Texas, Florida, Louisiana, North Carolina, Georgia, and New York.

Whichever lane fits, price the whole project before you fall for a machine. Compare real installed numbers across the brand directory, and use the sizing tools to check capacity before a salesperson sizes it for you.

Frequently Asked Questions

Why does a whole-house generator cost so much more than the sticker price?

Because the machine is half the project. The $3,000 to $6,000 unit needs a concrete pad, a correctly sized gas line, often a meter upgrade, an automatic transfer switch, an electrician, a plumber, and permits. Add it up and the finished project is $12,000 to $18,000 installed. The product page only shows you the machine.

What is the real installed cost of a 22kW Generac?

Plan for $12,000 to $18,000 installed for a typical 22kW to 24kW unit, even though the machine itself is around $4,000 to $6,000. The final number depends on your gas line, a possible meter upgrade, the electrical runs, and whether your panel needs work. Get two or three quotes after a site survey, not before.

Can I install a standby generator myself to save money?

Almost never worth it, and often not legal. A standby ties into your gas supply and main panel, needs permits and inspections, and requires a transfer switch wired so it cannot backfeed the grid. Most jurisdictions require a licensed electrician and plumber, and a DIY install can void both the warranty and your insurance. This is the one lane where the trades earn their fee.

Is a portable with an interlock really enough for a whole house?

For short, occasional outages, often yes, at a tenth of the cost. A $700 to $2,500 portable plus a $400 to $850 interlock powers your key circuits: fridge, furnace blower, well pump, a few lights and outlets. What you give up is automatic switchover and running everything at once. If your outages are a few hours a few times a year, that is a smart trade.

What surprise costs turn a generator quote into a bigger bill?

Three usual suspects: an undersized gas line, a gas meter the utility has to upgrade, and a panel with no room for the transfer switch. Any one can add $1,500 to $3,000. That is how a $9,400 quote becomes a $16,000 invoice. A proper site survey catches them before you sign, so the first quote should always follow a site visit.

How much does it cost to run and maintain a standby generator each year?

Budget $200 to $400 a year for a service contract, plus a starting battery every two to three years and periodic oil changes. The weekly self-test burns a little fuel and makes some noise. Not a large number, but a recurring one, so include it from day one. Full detail is in generator maintenance cost.

Is a home battery cheaper than a whole-house generator?

Not usually cheaper, but sometimes the better fit. A home battery runs $10,000 to $30,000 installed, similar to a standby project, and wins on silence, indoor safety, and zero fuel for short outages. It loses on multi-day outages, where a generator keeps going and a battery runs down. If your outages are short and noise rules strict, weigh it at homebattery.guide.

What we could not verify

The cost bands themselves. The $3,000 to $6,000 machine and $12,000 to $18,000 installed figures are this site's own, built from manufacturer catalogues and the six state cost pages. The national cost aggregators that publish averages block automated retrieval, so nothing here is sourced to one.
Freight, startup, first service and haul-away prices. No primary source publishes a residential range for any of them. They are named as rows to demand on a quote, not priced.
The worked example. It is illustrative, built from the line items on this page, not a specific homeowner's invoice. We have not published a library of reviewed quotes.