The planning ranges
Commercial generator pricing is quoted per installed kW, and the per-kW price falls as size rises:
| Size class | Turnkey installed (planning range) | Example project |
|---|---|---|
| Under 150 kW | $500–900 / kW | 100 kW ≈ $50,000–90,000 |
| 150–600 kW | $350–650 / kW | 300 kW ≈ $105,000–195,000 |
| Over 600 kW | $250–500 / kW | 800 kW ≈ $200,000–400,000 |
Two adjustments before you run your own number:
- Equipment-only ≈ 55% of turnkey. If you already have a contractor and only need the genset and switchgear supplied, budget a bit over half the installed figure. The other ~45% is the pad, electrical work, fuel system, rigging, permits and startup.
- Heavy verticals plan +25%. Healthcare, nursing homes, data centers, cold storage and manufacturing carry code, redundancy and integration requirements that push the whole band up about a quarter. A 150 kW clinic project plans at roughly $440–815/kW — call it $66,000–122,000 turnkey.
These are planning ranges for budgeting and comparing bids — not quotes. Sites differ enormously; a supplier confirms the real number on a site visit.
Why the bands are so wide
Two 100 kW projects can land $40,000 apart and both be fairly priced. Six line items do most of the moving:
1. Fuel type and fuel infrastructure
A diesel unit adds a sub-base or standalone tank, spill containment and fuel-system permitting. A natural gas unit skips the tank but may need the gas service upgraded: as a planning line, gas piping and trenching commonly runs $5,000–15,000, and the utility must confirm the meter can feed the generator's full demand at pressure. Whichever fuel you pick, its infrastructure is a real slice of the invoice — get both configurations quoted before assuming one is cheaper.
2. Enclosure and siting
An open-skid unit inside a plant room costs less than a Level-2 or Level-3 sound-attenuated outdoor enclosure. Noise-sensitive sites — property lines, patios, urban infill — push toward the quieter, more expensive package, and rooftop or tight-access placements add rigging and structural cost.
3. The transfer switch (and how many)
Every project needs at least one automatic transfer switch, sized to the electrical service it sits in — not to the generator. Service-entrance-rated switches, closed-transition models, and multi-switch layouts (separating life-safety from optional loads, as codes often require) each add cost. On small projects the ATS and its wiring are one of the biggest single variables.
4. Electrical and civil work
The concrete pad, conduit runs, feeder cable distance, panel modifications and any service upgrade are pure site-dependent cost — this is the main reason the install share of a project commonly runs 25–50% of the budget, and the main thing a site visit prices.
5. Permitting
Plan $500–5,000 for permits across building, electrical, fuel and air-quality jurisdictions. Air permitting matters more for diesel: standby units typically run under the EPA emergency-engine provisions (40 CFR 60 Subpart IIII), but strict air districts add process, and non-emergency use changes the emissions tier — and the price class — entirely.
6. Life-safety commissioning
If the generator serves life-safety loads, NFPA 110 brings acceptance testing, documentation and integration requirements — as a planning line, $3,000–15,000 for commissioning on covered projects. This is a major reason the healthcare and senior-care bands sit 25% high. Verify the specifics with your AHJ.
Equipment-only vs turnkey: which should you buy?
| Scope | You get | Budget anchor |
|---|---|---|
| Equipment-only (supply) | Genset + ATS delivered; your contractor installs | ≈ 55% of turnkey |
| Turnkey | Design, permits, pad, electrical, fuel, startup, commissioning | The full band above |
Turnkey concentrates responsibility — one party owns the outcome, which matters when the outage comes. Equipment-only can save money when you already have a qualified electrical contractor engaged on a larger buildout. Either way, compare bids on the same scope: the cheapest number in a stack of quotes is usually missing a line item, not beating the market.
How to build your own budget number
- Size first. Cost per kW is meaningless until you know the kW — run the sizing method or the selector wizard.
- Pick the band for your size class; apply +25% if you're a heavy vertical.
- Add site flags: no gas service nearby, long feeder runs, sound limits, life-safety loads — each pushes you toward the top of the band.
- Get real bids. Post your project with your kW and site details and let dealers and contractors price it competitively — or request a quote directly. Our planning tools help you pressure-test what comes back.
Frequently asked questions
How much does a 100 kW commercial generator cost installed?
Planning range: about $50,000–90,000 turnkey ($500–900/kW), with the equipment itself around 55% of that. Healthcare, data-center, cold-storage and manufacturing sites plan roughly 25% higher. A supplier confirms on a site visit.
Why is the price per kW lower for bigger generators?
Fixed costs — engineering, permitting, mobilization, controls — spread over more kilowatts, and larger engines cost less per unit of output. That's why 150–600 kW projects plan at $350–650/kW versus $500–900/kW below 150 kW.
Is natural gas or diesel cheaper to install?
It depends on the site, not the machine. Diesel adds tank, containment and fuel permitting; gas adds line sizing and possible trenching ($5,000–15,000 as a planning line). Where adequate gas service already reaches the pad, gas often installs cheaper; where it doesn't, diesel usually wins. Compare the fuels here.
What does the transfer switch add?
The ATS is priced by amperage, transition type and service-entrance rating, plus its wiring. On small projects it is one of the largest single line items after the genset itself — and code may require more than one switch. See the ATS guide.
Turn the range into a real number
The bands above bracket honest projects; your site picks the point. Post your project — industry, state, size or square footage, fuel preference — and it arrives to dealers pre-scoped with a recommended size and cost range, so the bids you get back are comparable. Prefer to talk first? Request a quote.