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Generator Installation Cost: Portable vs. Standby in 2026

The Tradesman's Playbook · Updated October 2026
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A customer calls after a 48-hour power outage. They want a generator. Portable or standby? Here is the full cost math for both, when each makes sense, and every line item that goes into a professional install.

Portable Generator Install

A portable generator ($800–$3,000 depending on wattage) is a legitimate backup for occasional short outages. To use one safely, you need:

  • A manual transfer switch or inlet box: $300–$800
  • Dedicated inlet receptacle (NEMA L14-30 for 7.5 kW, L14-50 for 12 kW): included with transfer switch
  • Short feeder from inlet to panel: $200–$400 materials + labor
  • Labor install transfer switch: $600–$1,200 (4–8 hours)
  • Permit: $100–$200

Portable install total: $1,200–$2,500 beyond the generator cost. The customer buys gas, hauls the generator out of storage, starts it, flips the transfer switch, and runs essential circuits.

Portable advantages: lower upfront cost. Portable disadvantages: fuel storage, start/stop by hand, limited runtime, no automatic switchover, noise close to the house.

Standby Generator Install

A standby generator (Generac Guardian, Kohler, Briggs & Stratton) runs natural gas or propane, starts automatically within 10–30 seconds of outage detection, and powers the home via an automatic transfer switch (ATS). Install scope:

Equipment

  • Generator unit: 14 kW ($3,500–$5,000), 20 kW ($4,500–$6,500), 24 kW ($6,500–$9,000)
  • Automatic transfer switch (ATS): $1,000–$2,500 depending on amperage and features
  • Load management module (if essential circuits only): $200–$500

Site Prep

  • Concrete pad (4" slab, 4-6 ft on each side): $400–$800
  • Composite pad alternative (manufacturer-approved): $150–$300
  • Setback verification (18" from building, 60" from windows typical)

Gas Supply

  • Natural gas line (if available): tap existing line, run to generator location. 50 ft run: $400–$900.
  • Propane install: new 500-gallon tank ($800–$1,500 if customer owns, $0–$200 lease), gas line: $300–$800
  • Gas sizing: 20 kW generator needs ~210,000 BTU/hr. Verify meter and line are sized adequately — may require utility upsizing ($300–$1,500 if required).

Electrical

  • Service entrance wiring from utility meter to ATS: 4/0 copper or aluminum, 10–20 ft typical. $300–$700.
  • ATS to main panel: 4/0 feeder, 5–10 ft. $200–$500.
  • Battery for generator (12V, included)
  • Low-voltage sensing wire from generator to ATS: included

Labor

  • Site walk, utility coordination: 2–4 hours
  • Pad install: 2–4 hours
  • Generator placement + anchor: 1–2 hours (often with a 2-person lift)
  • Electrical: 6–12 hours
  • Gas: 2–4 hours (plumber or combo electrician/plumber crew)
  • Commissioning + testing: 2–3 hours
  • Total: 20–30 hours labor at $100–$150/hr = $2,000–$4,500

Permits and Inspection

  • Electrical permit: $150–$400
  • Gas/mechanical permit: $150–$300
  • Building permit (pad): $75–$200
  • Final inspection scheduling

Total Install Range

Low end (14 kW, propane, simple site): $9,500–$12,500

Mid-range (20 kW, natural gas, 200A service): $13,000–$16,500

Complex (24 kW, long gas run, panel upgrade, load management): $17,000–$22,000

Sizing the Generator

Essential-circuits approach (10–14 kW):

  • Refrigerator/freezer
  • Furnace/boiler blower
  • Well pump
  • Sump pump
  • Lights and outlets in key rooms
  • Internet modem
  • Microwave or coffee maker

Whole-home (17–22 kW): adds central AC, electric water heater, electric range (via load management), limited electric heat.

Whole-home with EV or heavy loads (24–26 kW): everything plus EV charging and electric heat pumps.

Service Agreement

Standby generators need annual maintenance — oil change, air filter, spark plug check, battery test, exercise cycle verification. Price a $200–$400 annual service agreement into every install quote. It is recurring revenue and ensures the generator actually works when needed. A generator that has not run in 3 years fails to start in 50%+ of real outage events.

Build the Quote

Use the Generator Installation Cost Calculator to price by generator size, fuel type, run length, and electrical scope. The calculator produces a line-item quote that reflects the real complexity of a standby install.

Frequently Asked Questions

How much does a whole-home standby generator cost installed?

A 20–22 kW standby generator installation runs $12,000–$18,000 in 2026. The generator itself is $4,500–$7,000 (Generac, Kohler, Briggs). Add $1,500–$3,000 for the automatic transfer switch (ATS), $800–$2,000 for the concrete pad and gas line, and $3,000–$5,000 in labor and permits.

Is a standby generator worth it compared to a portable?

Depends on outage frequency and length. For homes with 1–2 short outages per year, a $1,500 portable generator with a manual transfer switch is adequate. For areas with frequent or extended outages (ice storms, hurricanes, grid instability), a standby generator starts automatically within 10–30 seconds, runs natural gas or propane (no refueling), and powers the whole home. The $15,000 install pays back in storage headaches alone.

How large a generator do I need for my home?

A 10–14 kW generator powers essentials (fridge, lights, outlets, well pump, limited HVAC) with load management. A 17–22 kW handles whole-home including central AC. A 24–26 kW handles homes with electric heat or EV chargers. Size by load calculation — oversizing wastes money, undersizing fails during actual outages.

Do standby generators require a permit?

Yes — electrical permit ($150–$400), mechanical/gas permit ($150–$300), and in many jurisdictions a building permit for the concrete pad ($75–$200). Setback requirements from windows, doors, and property lines are enforced. Noise ordinances apply in some areas (typically 70 dB at 25 ft is the limit). Permit scope is non-trivial — build it into the quote.