Whole House Generator Cost Calculator & Price Guide

A whole house generator, also called a home standby generator, is a permanently installed unit that sits outside on a pad and runs on natural gas or propane. When the grid goes down, an automatic transfer switch disconnects your home from utility power and starts the generator, usually within seconds. When power returns, it switches back and shuts the generator off.

That convenience is why a home generator costs far more than a portable one. You are paying for the unit, a licensed electrician to connect it to your panel, a plumber or gas fitter to run fuel to it, a concrete or composite pad, and local permits. The total depends most on generator size, how far the unit sits from your gas meter and electrical panel, and local labor rates. Figures on this page were checked on Oct 11, 2026.

An installed price bundles several separate costs. Seeing them line by line makes it easier to compare quotes.

The generator unit is the widest range, because price climbs with output. An air-cooled unit sized to run essential circuits sits at the low end, while a large liquid-cooled unit that can power a big home with central air sits at the top.

Installation labor at $4,520 covers setting the unit, wiring, and startup. The transfer switch, at about $1,200 installed, is the device that makes the system automatic. The natural gas line is priced per foot, so a generator placed close to the gas meter costs less to connect than one on the far side of the house.

There is no single number for every house, but you can build a rough estimate from the figures above.

1. Pick a size. List what you need to run during an outage: refrigerator, furnace or heat pump, well pump, sump pump, medical equipment, central air. An electrician can do a load calculation. Coverage for essential circuits needs a smaller generator than whole-home coverage.
2. Price the unit. Start from the generator unit range above and place yourself low or high based on size.
3. Add installation. Add the installation labor and transfer switch figures.
4. Add the fuel line. Measure the distance from the gas meter or propane tank to where the generator will sit, then multiply by the per-foot gas line cost of $15 – $20/linear ft.
5. Add site extras. Include a pad, permits, and any panel upgrade your electrician says is needed. Ask local contractors for these, since they vary by town.

The result will not replace a site visit, but it tells you whether a contractor's quote is in a reasonable range.

Standby generators are rated in kilowatts. Smaller units are meant to run a handful of essential circuits through a dedicated subpanel. Larger units, paired with a whole-home transfer switch, can run nearly everything in the house at once, including central air.

An oversized generator costs more to buy and burns more fuel, while an undersized one can trip or fail to start large appliances. Some transfer switches include load management, which turns off high-draw appliances like air conditioners when the generator nears capacity. That can let a mid-size unit handle a larger home.

Most standby generators can run on either fuel, and the choice usually comes down to what your home already has.

• Natural gas is the simplest option if you already have a gas line. Supply is continuous during an outage, and there is no tank to refill. Your gas meter may need upgrading if the generator and other gas appliances exceed its capacity, and the utility decides that.
• Propane works for homes without natural gas service. It requires an above-ground or buried tank, which adds cost and needs refilling. Generator output is often rated slightly differently on propane than on natural gas, so check the spec sheet.

Diesel standby generators exist but are more common in commercial settings.

A home generator involves both electrical and gas work, so most jurisdictions require permits and inspections. Local codes and the manufacturer's installation manual set minimum clearances from windows, doors, vents, and property lines, because generator exhaust contains carbon monoxide.

Some homeowners associations restrict generator placement or noise. Check your HOA rules before signing a contract. A qualified installer should pull permits, schedule inspections, and handle the utility coordination for any gas meter changes.

This is not a DIY project. Connecting a generator to your panel without a proper transfer switch can backfeed power into utility lines, which endangers line workers and violates electrical code. Hire a licensed electrician and a licensed gas fitter, or a generator dealer who uses both.

The three estimates below all come from one publisher, This Old House, but from different articles that measure different things.

The narrowest range may describe the generator unit alone. The installation guide figure bundles the unit, labor, and transfer switch. The widest range may cover everything from a small essential-circuit system to a large whole-home unit with long fuel runs and site work. Use the installation guide figure for a typical installed job and the wider range to understand the extremes.

A standby generator makes the most sense where outages are frequent or long, where losing power creates real risk, or where someone at home depends on powered medical equipment. It also protects against frozen pipes, flooded basements when a sump pump stops, and spoiled food.

Ongoing costs include fuel during outages and routine maintenance such as oil changes, filters, and battery replacement, usually under a service plan or annual visit from the dealer. Most units also run a short self-test on a schedule, which uses a small amount of fuel.