Whole house generator cost: unit, installation, fuel and what it looks like per month

Whole house generator cost by size

Standby generators are sized by kilowatts. The right size depends on which circuits you want running during an outage: essentials only (fridge, furnace blower, some lights and outlets) needs far less than whole-house with central AC.

Typical ranges for air-cooled and small liquid-cooled units from cost guides and installer quotes. Brand, region and site conditions change the numbers.

What's in the installation price

• Automatic transfer switch (ATS) and panel work: the switch that moves the house to generator power without you doing anything.
• Gas or propane connection: a new natural gas line or a propane tank and regulator. Long runs from the meter add cost.
• Concrete or composite pad, placement clearances from windows and doors, and sometimes trenching.
• Permits and inspections for electrical and gas work.
• Startup, load testing and the first service.

Installation is often as much as the unit. Quotes that look cheap sometimes exclude the gas line or the transfer switch, so compare itemized quotes.

Running and maintenance costs

A standby generator runs a self-test weekly and needs an annual service (oil, filters, spark plugs), commonly a couple of hundred dollars a year or a service plan. Fuel during an outage depends on load: a mid-size unit on natural gas can consume several dollars an hour at full load, and propane customers need tank capacity for multi-day outages. Battery backups for the controller need replacing every few years. Budget a few hundred dollars a year on top of any loan payment.

Is a whole house generator worth it?

It depends on how often and how long your power goes out, what's at stake when it does, and whether a smaller option would do. For homes with a sump pump, medical equipment, a home office, well water or freezers full of food, in areas with ice storms, hurricanes or an unreliable grid, the answer is often yes. For short, rare outages a portable generator with a manual transfer switch, or a battery backup for a few circuits, costs a fraction. Standby generators can also matter for insurance of basements against sump failure, and some buyers value them at resale in storm states. Our location guides cover the storm markets where they're most common.

Generator cost per month

Illustrative monthly payments at 10.99% APR, standard amortization, no fees. Lenders set real rates after reviewing an application. Not an offer of credit.

Financing before storm season, when installers have capacity, is usually faster and cheaper than after an outage. Our generator financing page compares unsecured loans, installer plans and home equity options with example payments.

A worked example: the $13,800 standby generator

A 22 kW air-cooled standby generator for a 2,400-square-foot home with one central AC. Unit and 200-amp automatic transfer switch $6,900, electrical installation $2,400, natural gas line from the meter (40 feet) $1,600, composite pad and placement $600, permits and inspections $450, startup and first service $350, contractor overhead and profit $1,500: about $13,800. The homeowners financed it in March, before hurricane season, at an illustrative 10.99% over 84 months, about $236 a month, and applied a $500 utility rebate for load management to the first payments.

Natural gas vs propane, and sizing honestly

Natural gas needs no refuelling but depends on the utility line staying pressurised; propane needs a tank (often 250 to 500 gallons for multi-day outages, a separate cost if you don't have one) but is independent of the grid. On sizing, dealers sometimes upsell: a load calculation that includes a managed-load module for the AC can let a smaller unit cover more than you'd expect. Ask for the calculation in writing. Oversizing adds thousands up front and burns more fuel every test cycle.

Mistakes to avoid

• Quotes that exclude the gas line or transfer switch, which can double the price after signing.
• Placing the unit too close to windows; code clearances may force a costly relocation.
• Skipping the service plan; a generator that hasn't been serviced often fails in the first real outage.
• Buying in the week after a storm when prices and lead times peak.
• Financing on a promotional plan without checking for deferred interest and dealer fees in the price.

Questions to ask the generator dealer

1. What load calculation sizes this unit, and can I see it?
2. Does the quote include the transfer switch, gas line, pad, permits and startup?
3. What is the clearance plan for placement, and will it pass code?
4. What does the service plan cost, and how often does the unit self-test?
5. What is the warranty on the unit and on your installation?
6. Can I monitor the generator from my phone, and is there a subscription?
7. Is the price the same for cash as for your financing plan?

Essentials or whole house? Think in monthly terms

Financing changes how upgrades feel. The difference between a $9,500 generator and a $14,000 one is $4,500 as a lump sum, but about $77 a month over 84 months at an illustrative 10.99% APR. That is why the better option often gets chosen once the monthly figure is on the table. Just make sure the upgrade pays you back in comfort, durability or running cost, and not only in looks, because you'll be paying for it long after the novelty fades.

What lenders look at when you finance a standby generator

Unsecured home improvement loans are approved on the same five things whatever the project: your credit score and recent payment history, your income and how much of it already goes to debt, the amount you're asking for, how long you've had credit, and whether the application is complete. Lenders that fund standby generators usually see requests in the $7,000 to $25,000 range, and a request near the low end of that is approved more often and at a better rate than one near the top.

Four moves improve offers everywhere: reduce the amount (rebates, a smaller scope, a down payment), pay a card balance below about 30% of its limit before the next statement, have pay stubs or bank statements ready so the application is complete, and check options with a soft-pull pre-qualification before any hard application. If your score is on the lower side, a co-applicant with stronger credit can open better terms; they share full responsibility for the loan. Home equity products add two more checks: an appraisal or valuation and a cushion of equity the lender wants left after the loan, commonly 15% to 20% of the home's value.

Questions to ask every lender

1. What is the APR including fees, and is the rate fixed?
2. Is there an origination fee, and is it deducted from the loan amount?
3. Is any promotional period deferred interest or waived interest?
4. Is there a prepayment penalty?
5. When is the contractor paid, and when does my first payment start?
6. Does checking my options use a soft or hard credit inquiry?

Choosing the contractor

The quote is only as good as the company behind it. Get two or three itemized quotes from licensed, insured licensed electricians or certified generator dealers (gas work must be done by a licensed plumber or gas fitter in most states) on the same scope, confirm permits are included, and check reviews that go back more than a season. Read any financing documents separately from the work contract: the loan is with the lender, not the contractor. The Federal Trade Commission's guide to hiring a contractor, linked in the sources below, lists the warning signs, including pressure to pay the whole job up front and steering you to a lender before you've seen a written price.

Frequently asked questions