Generator Installation Cost: Standby and Whole-House Pricing (2026)

A standby generator keeps your home running when the grid goes down. With extreme weather events becoming more frequent and more homeowners depending on electricity for medical equipment, home offices, and EV charging, generator installations have surged. Here is what a generator costs, what size you need, and what the installation involves.

Standby vs Portable Generators

Portable generators ($500-$2,500). Gas or dual-fuel units that you wheel out and start manually during an outage. They power a few circuits via extension cords or a manual transfer switch. Output ranges from 3,000-12,000 watts. Good for occasional short outages where you only need to keep essentials running.

Standby generators ($3,000-$15,000+ for the unit alone). Permanently installed outside your home, connected to your electrical panel, and powered by natural gas or propane. They start automatically within seconds of a power outage and shut off when grid power returns. Output ranges from 10,000-48,000 watts. This is what most people mean by “whole-house generator.”

For the rest of this guide, we focus on standby generators since they require professional installation.

How Much Does a Standby Generator Cost?

Total installed cost: $5,000-$15,000+ depending on size and complexity.

Component	Typical Cost
Generator unit (10-24 kW)	$3,000-$8,000
Automatic transfer switch	$500-$1,200
Installation labor	$1,500-$3,500
Concrete pad	$200-$500
Gas line connection	$500-$2,000
Permit and inspection	$100-$500
Total (mid-range 16-22 kW)	$7,000-$12,000

Larger whole-house units (24-48 kW) that can power everything including central AC and electric ranges run $12,000-$20,000+ installed.

What Size Generator Do You Need?

Generator size is measured in kilowatts (kW). The right size depends on what you want to power during an outage:

Essential coverage (10-14 kW): $5,000-$8,000 installed. Powers lights, refrigerator, sump pump, furnace blower, a few outlets, and your Wi-Fi. Does not power central AC, electric range, or electric water heater.

Extended coverage (16-22 kW): $7,000-$12,000 installed. Powers everything above plus central AC (up to 3-ton), electric water heater, and most household circuits. This is the most common residential size.

Whole-house coverage (24-48 kW): $12,000-$20,000+ installed. Powers everything in the house simultaneously, including multiple AC systems, electric ranges, EV chargers, and high-draw appliances. Necessary for large homes or homes with all-electric systems.

Your electrician will perform a load calculation to determine the right size. This accounts for which circuits you want backed up and their combined draw.

The Transfer Switch

The automatic transfer switch (ATS) is the brain of the system. It monitors utility power, signals the generator to start when power is lost, and switches your home from grid to generator power. When grid power returns, it switches back and shuts down the generator.

Whole-house transfer switch: Connects to your main panel and can power every circuit. Simpler installation but requires a generator large enough for your full electrical load.

Load-management transfer switch: Prioritizes critical circuits and cycles power between them. This lets you use a smaller (cheaper) generator to cover more circuits by not running them all simultaneously. For example, it might alternate between the AC and the electric dryer rather than running both at once.

Transfer switch installation is included in most generator quotes. If yours does not mention it, ask.

Fuel Source Options

Natural gas. Most convenient if you have a gas line to your home. Unlimited fuel supply — no refilling needed. Slightly lower energy output per unit of fuel compared to propane, so the generator may be derated 10-15% on natural gas.

Propane (LP). Requires a propane tank (typically 250-500 gallon for whole-house backup). Propane stores indefinitely and delivers more energy per unit than natural gas. Tank installation or upgrade adds $500-$2,000 if you do not already have one of sufficient size.

Diesel. Less common for residential standby generators. More efficient but noisier, requires fuel storage, and fuel degrades over time without additives.

Most residential standby generators are dual-fuel (natural gas or propane), giving you flexibility.

Installation Process

1. Site assessment (1-2 hours). The electrician and/or generator dealer evaluates your electrical panel, fuel source, and placement options. The generator must be placed a minimum distance from windows, doors, and property lines per local code (typically 5-18 feet from the house depending on jurisdiction).

2. Permit (1-2 weeks). Electrical and sometimes gas permits are required. Your installer handles both.

3. Concrete pad (1 day). A level concrete or composite pad is poured or placed where the generator will sit.

4. Gas line connection (half day). A licensed plumber or gas fitter runs a dedicated gas line from your meter or propane tank to the generator.

5. Electrical installation (1 day). The electrician installs the transfer switch at your panel, runs wiring to the generator, and connects everything.

6. Startup and testing (1-2 hours). The generator is started, load-tested, and the automatic transfer is verified.

7. Inspection (1-5 days). Local inspector signs off on electrical and gas work.

Total timeline: 2-4 weeks from signing the contract to a running generator.

Ongoing Costs

Standby generators are not install-and-forget. Budget for:

• Annual maintenance: $200-$500. Includes oil change, filter replacement, spark plug check, and load test. Most dealers offer annual service plans.
• Fuel cost during outages: Varies. A 20 kW generator running at half load uses roughly 1.5 gallons of propane or 200 cubic feet of natural gas per hour.
• Weekly exercise cycle: The generator runs for 10-15 minutes per week to keep the engine ready. Fuel cost is minimal.

FAQ

How long does generator installation take?

From contract signing to operating generator, expect 2-4 weeks. The installation work itself takes 1-2 days. Most of the timeline is permit processing and scheduling.

Do I need a permit for a standby generator?

Yes. Generator installations require an electrical permit and usually a gas/plumbing permit. Some jurisdictions also require a building permit for the concrete pad. Your installer handles all permits.

How loud is a standby generator?

Modern standby generators operate at 60-70 decibels at 23 feet, roughly the volume of a normal conversation. This is significantly quieter than portable generators (70-90+ dB). Noise ordinances vary by municipality — your installer will confirm placement meets local requirements.

How long can a standby generator run continuously?

With a natural gas connection, indefinitely (as long as gas service is active). With propane, runtime depends on tank size and load. A 500-gallon propane tank powering a 22 kW generator at half load runs approximately 4-5 days before needing a refill.

Will a generator power my whole house?

It depends on the generator size and your electrical load. A 22 kW generator handles most homes with central AC. Larger homes with multiple AC units, electric vehicle chargers, and all-electric appliances may need a 30+ kW unit. Your electrician performs a load calculation to determine the right fit.

Does a generator increase home value?

Standby generators add $3,000-$5,000 to perceived home value in areas prone to outages, according to real estate industry estimates. In hurricane-prone and severe weather regions, a whole-house generator is a significant selling point.