What size generator do I actually need?

It depends on which circuits you want powered during an outage. An essentials-only setup (refrigerator, well pump, a few lights and outlets) can work with 10-14kW, while powering most or all of a home, including central AC, typically needs 20kW or more. An electrician can calculate your home's specific load requirements.

How long does a whole-house generator installation take?

A typical installation takes 1-3 days for the physical work (pad, unit placement, electrical, gas line), though the full process including permits, gas company coordination, and inspection can take several weeks from order to final sign-off.

Do standby generators need regular maintenance?

Yes — most manufacturers recommend annual professional maintenance plus periodic self-tests (many units run a brief automatic test weekly). Skipping maintenance is a common reason a generator fails to start during an actual outage.

Is a whole-house generator worth it if outages are rare in my area?

That's a genuinely personal cost-benefit call — factors include how often you lose power, whether you have medical equipment or a home business that depends on continuous power, your climate (heating/cooling loss risk), and whether a cheaper portable unit or battery backup would cover your actual needs instead.

Whole House Generator Cost: Installed Price Guide

Prices updated July 21, 2026

HomeRepairPrice Editorial Team

A whole-house standby generator costs $8,000 to $15,000 installed on average, with the full range spanning $6,000 for a smaller essentials-only unit up to $39,000 for a large liquid-cooled system. The generator itself is only part of the bill — transfer switch, gas line, concrete pad, and electrical work typically add several thousand dollars on top of the unit price. See our electrical repair cost guide for how this compares to other electrical work.

Cost by generator size

2026 installed pricing by size

Item	Installed Cost	Typical Use
10-14 kW (essentials only)	$6,000 – $9,000	Fridge, well pump, a few circuits
14-16 kW	$12,300 – $21,400	Most of a mid-size home
20-22 kW	$9,000 – $25,000	Whole home for many houses; pricing varies significantly by source
26 kW	$11,000 – $16,000	Larger homes
35 kW liquid-cooled	$22,400 – $39,100	Very large homes, full HVAC load

The 20-22kW band shows the widest disagreement across pricing sources — get quotes for your specific home's electrical load rather than assuming a single number in that range applies.

What's in the installed price

Typical cost breakdown

Item	Cost
Generator unit	$3,500 – $8,000
Automatic transfer switch	$500 – $1,500
Concrete pad	$300 – $600
Electrical work	$1,500 – $3,000
Gas line installation	$500 – $1,500
Permits	$200 – $500
Labor	$1,000 – $2,000

Standby vs. portable generators

Portable generators cost $400 to $3,000 with minimal install cost — you run extension cords or a manual transfer switch when the power goes out. Far cheaper upfront, but require manual setup during an outage and typically can't power a whole house.
Standby generators run on natural gas or propane, start automatically within seconds of an outage via the transfer switch, and can power some or all of a home's circuits — but installation alone (separate from the unit) can run $2,000 to $20,000 depending on site conditions.

Sizing and installation are electrician-dependent

The transfer switch, gas line coordination, and electrical hookup are licensed-electrician work, not something most homeowners handle themselves — for hourly labor context on that portion of the job, see Electrician Cost Per Hour: 2026 Rates Explained. If your home's panel is older or undersized for a large standby unit, you may also need panel work — see the panel pricing in our electrical repair cost guide.

Prices on this page are researched ranges compiled from multiple public contractor-pricing sources, not quotes from us or a guarantee of what you will pay. Actual costs vary by region, material choice, and job complexity — always get itemized quotes from licensed local contractors before committing to a project. See How We Price for our sourcing methodology.

Frequently Asked Questions

What size generator do I actually need?: It depends on which circuits you want powered during an outage. An essentials-only setup (refrigerator, well pump, a few lights and outlets) can work with 10-14kW, while powering most or all of a home, including central AC, typically needs 20kW or more. An electrician can calculate your home's specific load requirements.
How long does a whole-house generator installation take?: A typical installation takes 1-3 days for the physical work (pad, unit placement, electrical, gas line), though the full process including permits, gas company coordination, and inspection can take several weeks from order to final sign-off.
Do standby generators need regular maintenance?: Yes — most manufacturers recommend annual professional maintenance plus periodic self-tests (many units run a brief automatic test weekly). Skipping maintenance is a common reason a generator fails to start during an actual outage.
Is a whole-house generator worth it if outages are rare in my area?: That's a genuinely personal cost-benefit call — factors include how often you lose power, whether you have medical equipment or a home business that depends on continuous power, your climate (heating/cooling loss risk), and whether a cheaper portable unit or battery backup would cover your actual needs instead.

HomeRepairPrice Editorial Team

Our editorial team researches and cross-checks every price range against multiple contractor-facing sources (see our How We Price methodology) before publication. We are not a contracting company and do not sell leads, materials, or services.

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