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Whole-House Generator Cost in New Hampshire: Installed Prices and What Drives Them in 2026

Whole-house generators cost $9,000 to $30,000 installed in New Hampshire in 2026. See sizing, propane tank costs, electrical work, permits, and regional pricing.

Whole-House Generator Cost in New Hampshire: Installed Prices and What Drives Them in 2026

A whole-house standby generator in New Hampshire costs $9,000 to $18,000 installed in 2026 for a typical 18 to 26 kW air-cooled unit running on propane, and $15,000 to $30,000 for a liquid-cooled 30 to 48 kW unit that can carry a large home with electric heat or a well pump, a workshop, and central air. Those numbers are approximate and include the generator, the automatic transfer switch, the concrete or composite pad, the electrical work, the fuel connection, and the permit.

Demand for standby power in New Hampshire runs well above the national average. The December 2008 ice storm left parts of the state dark for two weeks, the October 2017 windstorm knocked out power to more than 300,000 Eversource and Unitil customers, and nearly every winter since has brought a nor'easter or a heavy wet snow event that takes down trees across the Lakes Region, the Monadnock area, and the Seacoast. Homes on private wells lose water when the power fails, and homes with oil or propane boilers lose heat because the burner and circulator need electricity.

Propane is the fuel of choice across most of the state since natural gas service is limited to the Manchester, Nashua, Concord, and Seacoast corridors. That affects the price, because a propane installation includes a tank and a regulator rather than a simple tap on a gas line.

Generator Sizes and Equipment Prices

An air-cooled 18 kW unit from a major manufacturer costs $4,500 to $6,000 for the generator and transfer switch, and it will run a 2,000-square-foot home's furnace or boiler, well pump, refrigerator, lights, and a few circuits of outlets. A 22 to 26 kW air-cooled unit costs $5,500 to $7,500 and adds capacity for a small central air conditioner or an electric water heater.

Liquid-cooled units start around 30 kW at $10,000 to $14,000 for the equipment and go up from there. They are the right choice for homes with electric baseboard heat, a heat pump as the primary heat source, or a large well pump, and for the lake houses around Winnipesaukee and Sunapee that run everything on electricity. A 48 kW liquid-cooled generator runs $16,000 to $22,000 before installation.

Sizing is done from a load calculation that adds up the wattage of the circuits you want covered, with the starting surge of motors like well pumps and compressors factored in. A 1-horsepower submersible well pump, common in New Hampshire, pulls a starting load that can dwarf its running load, and undersizing a generator for the well is the most frequent mistake in the state.

A good electrician runs the numbers rather than guessing from square footage.

Portable and Manual Transfer Alternatives

A 7,500 to 12,000 watt portable generator with a manual transfer switch or interlock kit costs $1,500 to $3,500 installed and covers the boiler, well pump, refrigerator, and a few lights. It requires someone to wheel it out, start it, and refuel it every 8 to 12 hours, which is the tradeoff.

For a primary residence where storms hit while you are away, or for anyone who cannot easily haul and refuel a portable unit in a storm, the automatic standby unit earns its price.

Installation Costs Broken Down

Electrical work is the largest installation line. Mounting the transfer switch, running the feeder from the generator to the panel, and wiring the control circuits costs $2,000 to $4,500 depending on the distance and whether the panel needs upgrading. Homes built before 1980 in Manchester, Nashua, Keene, and the mill towns often have 100-amp panels that need replacement before a whole-house transfer switch can be installed, which adds $1,500 to $3,000.

The pad and placement cost $300 to $800. Code requires clearance from windows, doors, and vents, and New Hampshire's snow load means the unit needs to sit where the roof does not shed onto it and where a plow will not bury it. A composite pad is standard; a poured concrete pad adds a few hundred dollars.

Fuel connection for propane includes the tank, the regulator, and the line. A 500-gallon aboveground tank, the usual size for a 22 kW generator expected to run several days, costs $1,500 to $3,000 to purchase or can be leased from the propane supplier for a smaller annual fee. Burying the tank adds $1,500 to $3,500 for excavation and a coated tank.

Trenching the gas line and the electrical conduit runs $15 to $30 per foot, so a generator placed 60 feet from the house costs more than one placed 15 feet away.

Permits and Inspections

New Hampshire requires an electrical permit pulled by a licensed electrician, and most towns require a building or mechanical permit as well, with fees of $75 to $300. The state's Office of Professional Licensure and Certification licenses electricians, and the propane connection must be made by a licensed gas fitter. Expect two inspections, one electrical and one for the gas line.

Regional Price Differences Around the State

The Seacoast and the southern tier from Nashua through Salem and Derry run 10% to 20% above the state average because of higher labor rates and demand from the Boston commuter market. A 22 kW installation that costs $12,000 in Claremont or Berlin may cost $14,000 in Portsmouth or Bedford.

Rural installations in Coos, Carroll, and Grafton counties can cost more for a different reason: travel. An electrician driving 45 minutes each way to a camp in Pittsburg or a farm outside Lancaster adds mileage and time. Ledge is the other rural cost, since trenching a gas line through granite costs several times the per-foot rate for soil, and it is common in the White Mountains and the Monadnock region.

Lake houses have their own quirks. Access on narrow shorefront roads, septic and well locations that limit where the generator can sit, and shoreland protection rules under the state's Shoreland Water Quality Protection Act can affect placement and cost. An electrician who works around Winnipesaukee, Squam, or Newfound regularly will know the constraints.

Operating and Maintenance Costs

A 22 kW propane generator burns roughly 2 to 3.5 gallons per hour under a moderate load, so a three-day outage can consume 150 to 250 gallons. At New Hampshire propane prices, that is $400 to $800 of fuel for a single long outage. A 500-gallon tank filled to its 80% capacity holds about 400 gallons, which covers most storm outages with a margin.

Annual maintenance costs $250 to $500 and includes an oil and filter change, spark plugs, a battery check, and a test under load. The generator runs a self-test weekly, and the battery typically lasts three to four years. Most manufacturers require documented annual service to keep the warranty, which runs five years on most residential units with extended plans available for $500 to $1,200.

Cold weather kits are worth the $200 to $400 in New Hampshire. They include a battery warmer and an oil heater that keep the unit starting reliably at 20 below, which is the temperature a January outage in the North Country can bring.

Choosing an Installer

The cleanest arrangement is a single licensed electrician or generator dealer who handles the equipment, the electrical, the pad, and coordinates the propane supplier. Some New Hampshire electricians are factory-authorized dealers and can service the unit for its whole life, which matters when a control board fails during a storm.

Get three quotes with the same generator size and compare them line by line. Ask about the transfer switch type, since a whole-house switch with load management costs more than a switch covering a subset of circuits but avoids the need to choose which rooms lose power. Ask whether the price includes the permit, the concrete or composite pad, the gas line, and the first-year service.

You can compare licensed electricians and generator installers across New Hampshire and check for factory authorization before requesting quotes.

Lead times matter after big storms. Following a major outage, dealers across the state sell out of popular sizes and installation calendars fill for two to three months. Ordering in spring or summer avoids the wait and usually gets a better price.

Our home energy and backup power guides on the blog cover the alternatives, including battery storage paired with solar, for homes where a generator does not fit.

Frequently Asked Questions

How much does a 22 kW Generac cost installed in New Hampshire?

Roughly $10,000 to $15,000 with a propane tank, transfer switch, electrical work, pad, and permits. Panel upgrades, long trenches, or ledge push the total higher.

Does a whole-house generator increase home value in New Hampshire?

Buyers in the Lakes Region, the North Country, and rural towns with frequent outages often view a standby generator as a selling point worth several thousand dollars. It rarely returns its full cost, but it can shorten time on market for homes on wells with oil or propane heat.

Can I run a standby generator on heating oil?

No. Residential standby generators run on propane, natural gas, or diesel. New Hampshire homes with oil heat usually add a propane tank dedicated to the generator, which is the reason propane installations dominate here.

How long can a standby generator run continuously?

Most air-cooled units can run for days with proper oil levels and fuel, and manufacturers recommend checking oil every 24 to 48 hours of continuous operation. A 500-gallon propane tank supports about a week of moderate use for a 22 kW unit.