Gas piping, the pad, the transfer switch, the electrician and the permit routinely add as much again as the generator itself.
What the install involves →Whole house generator cost is one of those numbers dealers prefer to quote as a monthly payment. Installed, an air-cooled standby unit for a typical American house lands somewhere between roughly $5,000 and $15,000 at the time of writing, and the spread is not random. It comes from six line items, each of which you can estimate before anyone visits your property.
The six line items
| Line item | Typical range | What moves it |
|---|---|---|
| Generator, air-cooled 10-26 kW | $3,000-8,000 | Size, brand, enclosure, warranty length |
| Automatic transfer switch | $500-2,000 | Whole-panel versus a load-shed subpanel |
| Pad and site prep | $200-800 | Gravel bed, poured pad, grading, trenching |
| Gas or propane connection | $500-3,000 | Pipe run, meter upgrade, tank purchase |
| Electrical labour | $1,500-4,000 | Panel distance, service size, conduit run |
| Permit and inspection | $100-600 | Jurisdiction, whether gas and electrical are separate |
All prices here are approximate and vary sharply by region and by how busy your local trades are after a storm season.
Equipment: what kilowatts cost
Air-cooled units in the 10 to 14 kW range are the entry point and cover a critical-loads plan comfortably: well pump, furnace, fridge, freezer, lights and outlets. Move up to 18 to 26 kW and you are buying the ability to ignore the outage entirely, including central air and an electric range. Above that you are into liquid-cooled machines, which start around $15,000 for the equipment alone and are built for large houses or small commercial buildings.
Bigger is not automatically better here. A larger engine idles at higher fuel consumption, costs more to service, and needs more clearance from the house. If you have already done the sizing arithmetic, you may find a 14 kW unit does everything you actually care about for several thousand dollars less than the 22 kW the salesman leads with.
The pad and where it can legally sit
Standby units sit outside on a composite or concrete pad, and their placement is governed by manufacturer clearances and local code rather than by where you would like it. Manufacturers typically require on the order of eighteen inches of clearance from the wall and around five feet from any door, window or vent opening, with additional clearance above and to the sides for airflow and service access. Check the specific installation manual and your local rules before you promise yourself a spot.
Distance is money. Every extra foot between the generator, the gas source and the electrical panel is more conduit, more pipe and more labour, and a long run can quietly add a thousand dollars to a quote.
Gas is the line item that surprises people
A standby generator is a large gas appliance. On natural gas, the existing meter and pipe often cannot supply the additional demand at the pressure the unit needs, so the utility upgrades the meter, or the installer runs a larger diameter line, or both. That is where a $600 estimate becomes $2,500.
On propane, you need tank capacity to match. A 22 kW unit at roughly half load consumes somewhere in the region of two and a half to three and a half gallons an hour, so a 500 gallon tank filled to the usual 80 percent gives you on the order of five days of continuous running. Buying a 250 or 500 gallon tank typically costs between $700 and $3,000 installed; many suppliers lease instead, which lowers the up-front figure and locks you into their fuel pricing.
The electrical side
Two choices drive the cost. A service-rated automatic transfer switch handles the entire panel and lets the generator carry whatever it can, usually with load-shed modules that drop the air conditioning when the well pump starts. A smaller transfer switch feeding a critical-loads subpanel is cheaper, but somebody has to decide which circuits move, and moving them is labour. The full comparison is in the transfer switch guide.
What it costs to keep
- Annual service, typically $200 to $500, covering oil, filter, plugs, valve check and a load test.
- A weekly self-test cycle of ten to twenty minutes, which burns a small amount of fuel and annoys neighbours who are home on Tuesday mornings.
- Battery replacement every three to five years, since the unit starts on a small lead-acid or AGM battery that fails silently.
- Propane top-ups after every real outage, at whatever the delivery price is that week.
Two reasons to buy a portable instead
If you lose power twice a year for six hours, a standby unit is a $12,000 solution to a $1,200 problem, and the interest on the financing exceeds the value of the inconvenience avoided. And a standby unit is a fixed asset: it stays with the house when you sell, it cannot help at a cabin or a relative’s place, and it cannot be borrowed. A portable plus a properly installed interlock kit gives you most of the capability for well under a fifth of the money, at the cost of walking outside in the weather to start it.
Where the money is well spent
Standby generators earn their keep in three situations: outages that regularly run past a day, a household where somebody depends on powered medical equipment, and a house nobody is home to babysit, such as one with a sump pump and a finished basement. Outside those cases the honest answer is that a 7,500 W dual-fuel portable, an interlock and a stack of propane cylinders solve the same problem for a tenth of the price. Get three written quotes with the six line items itemised separately, and be sceptical of any quote that gives you a single number, because that is where the margin hides.
Frequently Asked Questions
How much does a 22kW Generac cost installed?
For a 20 to 24 kW air-cooled unit, expect roughly $10,000 to $15,000 installed at the time of writing, with the generator itself accounting for around half and gas piping and electrical labour for most of the rest.
Does a whole house generator add value to a home?
It is a selling point in areas with frequent or long outages and close to irrelevant elsewhere. Treat any resale recovery as a bonus rather than as part of the justification for the purchase.
Can I install a standby generator myself?
You can do site prep and set the pad. The gas connection and the transfer switch tie-in require permits and, in nearly every jurisdiction, licensed trades. Doing it unpermitted risks your insurance coverage as well as the inspection.
How long does a standby generator last?
Air-cooled units are generally rated in the region of 1,500 to 3,000 running hours before major service, which for a house that uses it a few dozen hours a year translates into decades. Neglected oil changes shorten that dramatically.