Cost guides
Whole-House Generators: What the Unit Costs and What the Install Costs
The sticker price is only part of it. The transfer switch, the pad, the gas line and the permits, with national price ranges and the safety rules that aren't optional.
How much is quiet worth? Not silence, which you won’t get with a generator running in the side yard, but the other kind: a refrigerator humming, a fan turning, a sump pump doing its job three days after the power went out and the neighbors started grilling everything in their freezers.
That’s what people are really buying. Here’s what goes into the number.
The Unit
National figures from HomeAdvisor, updated this year, put the generator alone at roughly:
- 14 to 18 kW: $4,000 to $5,500
- 20 to 24 kW: $5,000 to $6,500
- 26 to 32 kW: $6,500 to $15,000
As for size, Generac says a 10 kW unit covers essential circuits like lights, refrigeration and small appliances, while a 2,000-square-foot house typically needs a 20 or 22 kW unit for whole-home coverage. It also says a professional site survey “is the only way to ensure full accuracy.” (Generac)
The Install
This is where the estimate grows. HomeAdvisor’s ranges:
- Labor: $1,500 to $5,000
- Concrete pad: about $1,000 for a typical pad
- Propane tank, if you don’t have natural gas: $300 to $1,500
- Permits: $50 to $200 each, and most jobs need one for the electrical work and one for the fuel
The same source puts its overall average, which includes smaller units, at $5,157 installed, with a typical range of $1,512 to $8,803. Treat any single number as a starting point. Every house is different.
A transfer switch isn’t an option. Generac calls it “a required part of a properly installed home standby generator system.” It separates generator power from the utility and prevents backfeeding. (Generac)
Placement has rules too. Generac’s clearance guidance, based on the NFPA 37 standard, calls for 5 feet from operable windows, doors and vents, with local codes taking precedence. (Generac) In a neighborhood with an architectural review board, expect a conversation about where it goes and what screens it.
Permits Here
The towns don’t publish a generator page, but the general rules cover it. Hilton Head requires a permit to install or alter electrical equipment. (Town of Hilton Head Island) The City of Beaufort requires one to install or replace any electrical or gas system. (City of Beaufort FAQ) Your installer should pull them. See who issues permits where.
The Part That Isn’t About Money
Portable generators were associated with an estimated 858 carbon monoxide deaths from 2011 to 2021, according to the Consumer Product Safety Commission. (CPSC, February 2025) The CPSC says to run a portable unit at least 20 feet from the house and never to power the house by plugging a generator into a wall outlet, known as backfeeding, which can electrocute utility workers and neighbors. (CPSC) A standby unit installed with a transfer switch takes most of that risk off the table, which is part of what the install money buys.
Keeping It Ready
Generac’s Schedule A maintenance comes every two years or every 200 hours, whichever comes first, with an oil and filter change every 100 hours when it runs in heat above 85 degrees. (Generac) Around here, that’s a lot of summer. Ask who services it and what that costs before you sign.
The Sound of the Lights Coming Back
A standby generator is insurance you can hear. You pay up front for something you hope sits idle, and then one September night the street goes dark, your generator clears its throat, and the kitchen light comes back on. That’s the moment most owners stop thinking about what it cost.