How Much Does Generator Installation Cost in Illinois in 2026?
A standard 22 kW whole-house generator costs $8,500 – $14,000 installed in Illinois (average vs. national average). The primary outage risk is severe storms & tornadoes. Best time to buy: september through january.
Why Illinois Needs Backup Power
Illinois faces severe thunderstorms and tornadoes in spring and summer, and bitter winter storms from November through March. The Chicago metro's dense tree canopy and older grid infrastructure make power outages a recurring frustration for ComEd customers.
The August 2020 derecho ripped across Illinois with 100+ mph winds, leaving hundreds of thousands without power for days. Power in Illinois is served by ComEd (Chicago metro), Ameren Illinois, MidAmerican Energy. According to the Illinois State Electricity Profile, the state averages 2 outages per year with a mean duration of 6 hours per event.
2
Outages/year
6h
Avg duration
Severe storms & tornadoes
Primary risk
Winter storms & extreme cold
Secondary risk
How Much Does It Cost in Illinois?
| Setup | Size | Cost Range (Installed) |
|---|---|---|
| Essential circuits | 10-16 kW | $5,500 – $9,500 |
| Whole house | 20-22 kW | $8,500 – $14,000 |
| Large home / liquid-cooled | 24-48 kW | $13,500 – $21,000 |
Near the national average overall. Chicago and the North Shore are above average due to union labor rates and city code complexity. Downstate Illinois is below average. For a full national breakdown, see our installation cost guide. Not sure what size you need? Use our sizing guide.
Illinois-Specific Installation Requirements
Local Building Code
Illinois follows the NEC. Chicago has its own electrical code, which is stricter and requires city-licensed electricians. Suburban Cook County follows the county code.
Additional code-related cost: $100 – $500
Permits
Permit timeline: 1-3 weeks. Cost: $100 – $350. Your installer handles the filing and inspection.
Preferred Fuel: Natural Gas
Nicor Gas and Ameren serve most of the state. Chicago suburbs have extensive natural gas infrastructure.
Comparing brands? Read our Generac vs Kohler comparison.
Best Time to Buy a Generator in Illinois
September through January. Severe storm season peaks April through August.
How Much Does a Home Generator Cost?
Get an instant estimate based on your home size and power needs.
Recommended size
22 kW
Estimated cost
$7,700 – $12,100
Includes equipment, installation, transfer switch, and permits
As low as $83/month with approved financing
Prices vary by location. Enter your ZIP code for local estimates.
Generator Installation in Illinois by City
Frequently Asked Questions — Illinois
What size generator for an Illinois home?
Average IL home is about 2,100 sq ft. A 22 kW unit covers whole-house. Homes with electric heat may need 24 kW.
Is Chicago more expensive for generator installation?
Yes. Chicago requires city-licensed electricians and has its own electrical code. Expect 15-25% above suburban pricing.
How long does permitting take in Illinois?
1-2 weeks in most suburbs. Chicago proper can take 3-4 weeks due to the city's separate electrical code.
Are tornadoes a real risk in Illinois?
Illinois averages 50-60 tornadoes per year, ranking in the top 10 nationally. Central and southern Illinois are in the highest-risk zones.
Natural gas or propane in Illinois?
Natural gas in Chicago, suburbs, and most metro areas. Propane in rural downstate Illinois.
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