A permanently installed standby generator on Long Island runs about $8,000 to $15,000 for most houses, according to StandTech Electric’s 2026 pricing, and up to around $18,000 for a 22 kW unit that carries central air, by Marra Electric’s numbers. The unit itself is only part of the bill. The rest is the gas line, the transfer switch, the wiring, the pad and the permits.
Tropical Storm Isaias, August 2020
Tropical Storm Isaias knocked out power to more than 420,000 PSEG Long Island customers. RiverheadLOCAL reported that about 60,000 were still without power on the Saturday night after the Tuesday storm. WSHU reported on August 14, 2020 that PSEG had marked restoration complete, with 143 customers still out that Friday afternoon.
What goes into the price
StandTech Electric breaks down a Generac install on Long Island like this (May 2026):
| Part of the job | Price | Source |
|---|---|---|
| Generator, 10 to 14 kW, selected circuits | $3,500 to $5,500 | StandTech Electric |
| Generator, 16 to 22 kW, whole house with load management | $5,000 to $8,000 | StandTech Electric |
| Generator, 24 to 26 kW, whole house including central air and an electric range | $7,500 to $11,000 | StandTech Electric |
| Installation labor and materials, separate from the unit | $3,000 to $7,000 | StandTech Electric |
| Concrete pad or gravel base | $300 to $800 | StandTech Electric |
| Automatic transfer switch, installation | $800 to $1,500 | StandTech Electric |
| Gas line from the meter | $500 to $2,000 | StandTech Electric |
| Generator to panel wiring | $500 to $1,500 | StandTech Electric |
| Load calculation and panel work | $300 to $800 | StandTech Electric |
| Permits and inspections | $200 to $500 | StandTech Electric |
| Propane tank, if the house has none | $1,500 to $3,000 | StandTech Electric |
Marra Electric’s totals for Suffolk County come out in the same range: about $8,000 to $12,000 for a 14 to 16 kW system on selected circuits, and $12,000 to $18,000 for 20 to 22 kW covering the whole house.
Sizing it to the house
There are two ways to size a standby unit. A smaller generator, 10 to 14 kW, runs the circuits you pick: StandTech lists the refrigerator, sump pump, lights and a few outlets. A larger one, 16 to 22 kW and up, runs the whole house, with load management shedding big loads when needed. Marra Electric says most Suffolk homes need 16 to 22 kW for whole house coverage. Central air, an electric range, a well pump or pool equipment push the number up.
Both companies want a load calculation before they name a size, and Marra warns that an undersized generator cannot keep up with the house.
Natural gas or propane
A house with natural gas connects the generator to the gas line, and Marra Electric says that gives it effectively unlimited runtime. A house without gas needs a propane tank, typically 250 to 500 gallons by StandTech’s figures, and Marra notes propane usually costs more to run.
Either way, National Grid wants to know. Its Long Island generator safety sheet asks customers to notify National Grid Customer Service about a permanent standby generator on natural gas or propane, and warns that it may require an electric service upgrade by a qualified electrician. When a generator adds gas load, the contractor fills in National Grid’s LI Residential Meter Upgrade Request Form with the BTU rating of every existing and new gas appliance, signed by you and the plumber or contractor, and emails it to ngridmeterupgrades@nationalgrid.com. Technical questions go to 631-348-6063. National Grid says an incomplete form delays the application.
Where the generator can sit
Generac’s clearance guidance, based on the NFPA 37 standard:
| Clearance | Distance |
|---|---|
| From windows, doors, vents and window wells | 5 feet |
| From the house, units with the SwRI test logo | 18 inches |
| From combustible material, units without that logo | 5 feet |
| Above the unit | 5 feet |
| In front and at both ends, shrubs and trees included | 3 feet |
Generac says local codes take precedence over these numbers, and that even with the clearances met, exhaust can still find its way inside, so the unit may need to sit farther away. It also says to point downspouts, sprinklers and sump discharge away from the enclosure. Long Island towns and villages set their own setback and permit rules, so ask the installer what yours requires.
The transfer switch, and portable generators
National Grid requires a double throw transfer switch on a permanent install. It has to disconnect the house from National Grid’s system before the generator power comes on (break before make), be rated for the job under the National Electrical Code, and be listed by a recognized independent test lab. Marra Electric says the Generac and Kohler units it installs come with automatic transfer switches that sense the outage and switch over on their own.
If you are running a portable generator for now, National Grid’s rule is never to run it indoors, including the garage or a shed, and that open windows do not make it safe.
Permits and inspections
StandTech Electric says a generator on Long Island needs a building permit and an electrical permit, and that Nassau County and most Suffolk towns also require a plumbing permit for the gas line. It expects two inspections, one for the gas and one for the electrical and final. Marra Electric says the licensed electrician files the electrical permit, a licensed plumber handles the gas work, and the propane supplier usually takes care of tank permits. StandTech warns that unpermitted installs can lead to fines and insurance claim denials. The electrical inspection is usually done by a private agency; see the inspection agency guide.
Questions for each installer
- Will you do a written load calculation, and what will the unit I am buying actually run?
- Who on your team is the licensed plumber for the gas line, and who files the National Grid form?
- Where exactly will the unit sit, and does that meet my town’s setback?
- Is the transfer switch automatic, and is it included in the price?
- Are the pad, permits and both inspections in the quote?
- What does yearly service cost, and do you do it yourselves?
After it is in
The Electrical Safety Foundation recommends a full electrical inspection for homes 10 or more years old that add major new appliances, and a generator wired into the panel is a good moment for one on an older house.
Marra Electric recommends yearly service at about $200 to $300, which covers the oil and filters, battery, belts and hoses, a transfer switch test and a run under load. It says most units also exercise themselves for 10 to 15 minutes every week, so expect to hear it start up on its own.