When the power goes out for days, a whole-house standby generator is what keeps the sump pump running, the fridge cold, and the heat on — it starts automatically within seconds and powers the home until the grid returns. The catch is the price: the generator unit is often less than half the total bill. This guide breaks down what a standby generator actually costs installed in 2026, by size and brand, and where the rest of the money goes.
How much does a whole house generator cost? A whole-house standby generator costs $6,000–$15,000 fully installed in 2026, with a national average around $10,000. The unit itself is $2,500–$10,000 depending on size and brand; installation adds $3,000–$5,000 for the concrete pad, transfer switch, gas line, electrical work, and permits.
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Planning a standby generator? Post the job free on AllBetter and compare bids from identity-verified electricians — no lead fees, payment held in escrow until the install passes inspection.
One safety note up front: this guide is about permanently installed standby generators. Portable generators are a documented cause of carbon monoxide deaths every year — they must never run indoors, in a garage, or near a window. A standby generator is installed outdoors with proper clearances, which removes that risk entirely.
Whole House Generator Cost by Size
Generator capacity is measured in kilowatts (kW). The right size depends on what you need to run during an outage. Typical 2026 installed costs:
Most 2,000–3,000 sq ft homes land on a 16–22 kW unit. Ask the electrician for a load calculation before you buy — undersizing means the AC will not run, and oversizing wastes $2,000–$5,000 on capacity you never use.
What’s Included in the Installation
The generator unit is only 40–60% of the total. The rest of an $3,000–$5,000 installation breaks down like this:
- Automatic transfer switch — $500–$1,800. Detects the outage and switches the home from grid to generator power in seconds. Wired straight to your electrical panel.
- Concrete pad — $500–$1,200. A level pad to mount the unit, set to local setback rules (typically 5 feet from the house, 18 inches from windows).
- Gas line connection — $500–$2,000. A dedicated line from the meter; a propane tank adds $500–$2,500 if you do not have natural gas.
- Electrical labor — $1,500–$3,000. A licensed electrician installs the transfer switch and ties the generator into the panel — 6–10 hours for most jobs.
- Permits and inspection — $200–$500. Electrical and gas permits, required in most jurisdictions. Non-negotiable for code compliance.
An older 100-amp panel often needs an upgrade to handle a large generator — see our electrical panel upgrade cost guide. Older homes may also need partial rewiring; our electrical wiring cost guide covers that.
Quoted on a generator? Post the job on AllBetter and several verified electricians each size and bid it — you compare itemized quotes instead of accepting one bundled number.
Generac vs. Kohler vs. Briggs & Stratton
Three brands cover most of the residential standby market:
All three carry a 5-year warranty. For most homeowners the deciding factor is not the badge but the local dealer — a brand with a nearby authorized service network gets your generator back online faster after a fault.
Natural Gas vs. Propane vs. Diesel
The fuel source affects upfront cost, running cost, and reliability in a long outage:
- Natural gas — an unlimited supply from the utility line, no storage tank, cheapest to run ($0.50–$1.50 an hour). The default for most suburban homes.
- Propane — an on-site tank (250–1,000 gallons) that keeps working if gas lines are damaged; $1.50–$3.00 an hour to run, plus $500–$2,500 for the tank. Best for rural homes without natural gas.
- Diesel — the most fuel-efficient and longest-lasting, but louder and pricier upfront; mostly used on remote or commercial properties.
Annual Maintenance Costs
A standby generator needs annual service to be reliable when it counts. Budget for:
- Annual service — $200–$400 a year. Oil change, filters, spark plugs, battery test, transfer-switch inspection.
- Fuel while running — $12–$50 a day. Natural gas at the low end, propane at the high end; most outages cost $25–$200 in fuel total.
- Starter battery — $100–$200 every 2–3 years. A dead battery means the generator cannot auto-start — do not skip this.
How to Save on Generator Installation
- Get at least three quotes. Generator installation prices vary 30–50% between contractors for the same unit and scope.
- Buy off-season. Demand spikes after storms — buy in spring or early summer for better prices and shorter lead times.
- Choose natural gas if it is available. It skips the $500–$2,500 propane tank and ongoing tank fees.
- Bundle with panel work. If the panel needs upgrading anyway, doing both at once saves $500–$1,000 in labor.
- Hire the installer directly. A big-box or brand dealer subs the install to a local electrician and adds a coordination markup — on a five-figure job, removing that layer is real money.
How to Spot a Real Generator Pro
Generator installs are a magnet for upsells. A right-sizing pro and an equipment-pusher quote the same house very differently:
Lead-generation sites like Angi and Thumbtack charge contractors per lead, and that cost is built into your quote. On a marketplace with $0 lead fees, identity-verified electricians bid your job directly and payment is held in escrow until the install passes inspection. A standby generator can also be a resale advantage in storm-prone markets, where buyers increasingly expect backup power.
Whole House Generator Cost FAQ
How much does a whole house generator cost installed?
A whole-house standby generator costs $6,000–$15,000 fully installed in 2026. The unit is $2,500–$10,000 depending on size and brand; installation adds $3,000–$5,000 for the concrete pad, transfer switch, gas line, electrical work, and permits. The popular 22kW size typically lands around $10,000–$13,000 installed.
What size generator do I need for my house?
Most homes need a 16–22 kW generator to run all essential systems including central AC. A 7–10 kW unit covers basics — lights, fridge, sump pump — but will not power AC. Homes over 4,000 sq ft or with multiple AC units may need 30 kW or more. Ask your electrician for a load calculation to size it correctly.
Is a whole house generator worth it?
It is worth it if you face frequent outages, live in a storm-prone area, rely on medical equipment, work from home, or have a sump pump protecting a finished basement. For an area with rare outages, a portable generator may be enough.
How long does a whole house generator last?
A well-maintained standby generator lasts 20–30 years. That depends on annual service ($200–$400), a battery replacement every 2–3 years ($100–$200), and the weekly self-test the unit runs automatically.
How long does it take to install a whole house generator?
Installation takes 1–3 days for most homes: pour the pad and run the gas line, then place the unit and wire the transfer switch, then final inspection and testing. A straightforward install with existing gas service can be done in one long day.
Natural gas or propane for a standby generator?
Natural gas is the simpler, cheaper choice if your home has a utility gas line — unlimited fuel, no tank, and the lowest running cost. Propane is the answer for rural homes without natural gas; it needs an on-site tank ($500–$2,500) but keeps working when gas lines are damaged.
