How Much Does a Whole House Generator Cost in Illinois?

A whole house generator costs $8,000 to $18,000 installed for most North Shore homes in 2026. The generator itself is roughly half of that. The rest pays for the transfer switch, electrical work, the gas line, a pad, and permits. A typical 2,500 to 4,000 square foot home in Northbrook, Wilmette, or Highland Park lands between $12,000 and $18,000 with a 22 to 26 kW unit running on Nicor or North Shore Gas service.

That range sits above the national average, and there are real reasons why. National cost sites like HomeGuide put the average install at $6,000 to $11,000. North Shore homes tend to be larger. They need bigger units, longer gas runs, and more electrical work. Local labor rates run higher here too. This guide breaks down every line item, so you can read a quote and know exactly where the money goes.

What Does a Whole House Generator Cost in Illinois?

Expect $8,000 to $18,000 installed on the North Shore in 2026. The unit runs $4,000 to $8,000 depending on size. Installation adds the rest: transfer switch, wiring, gas piping, a pad, and permits. Bigger homes, longer gas runs, and older electrical panels push the total toward the top of the range.

Most installers quote one bundled price, so the line items won't always appear separately. The table shows where that bundled number comes from. On unit pricing, Generac lists its 22 kW Guardian at about $7,000 before installation and the 26 kW at about $7,900. Briggs & Stratton units land in a similar range, and our electrician handles Briggs & Stratton installations across the North Shore. Not sure which brand fits your house? See our honest Generac vs. Briggs & Stratton comparison for the warranty, price, and natural gas differences.

One honest note. A low quote is not always a good quote. If a bid skips the transfer switch, uses undersized gas pipe, or leaves permits out, the "savings" show up later as failed inspections and rework. A complete whole home generator installation covers all six line items above.

How Much Does a Generator Cost by Home Size?

Home size sets generator size, and generator size drives cost. A home under 1,500 square feet can run on 10 to 14 kW. A typical 2,500 to 4,000 square foot North Shore home needs 22 to 26 kW to carry air conditioning, a sump pump, and the kitchen at the same time.

The house itself matters as much as the square footage. An older Evanston two flat with 100 amp service needs different planning than a newer Northbrook build with 200 amp service and a short run to the gas meter. That's why two neighbors with same size homes can get quotes thousands of dollars apart. Not sure which kW number applies to your house? Our generator sizing guide walks through the chart and the appliance math before you ever request a quote.

What Makes the Price Go Up or Down?

Four things move a North Shore generator quote the most: the distance from your gas meter, the distance from your electrical panel, the condition of that panel, and the size of the unit. Short runs and modern panels keep you near $12,000. Long trenches and panel upgrades push toward $18,000.

• Gas line distance. Gas piping costs roughly $15 to $50 per foot installed. A generator placed near the meter might need 10 feet of pipe. One placed across the yard might need 60.
• Gas meter capacity. Your meter has to feed the generator plus your furnace and water heater at the same time. If it can't, Nicor or North Shore Gas has to upgrade it, which mostly adds weeks to the timeline. Homes without existing gas service sometimes go with propane instead; see our natural gas vs. propane cost comparison for the tradeoffs.
• Electrical panel condition. Homes with older 100 amp panels sometimes need panel work before the transfer switch can go in. Electricians in the Chicago area bill at the top of the national $50 to $130 per hour range.
• Placement rules. Villages enforce setback and screening rules for where the unit can sit. Tight side yards in Wilmette or Winnetka can limit placement options and add cost.

How Much Does a Whole House Generator Cost to Run?

Plan on $30 to $60 in natural gas for a full day of outage coverage. As of July 2026, the Nicor Gas supply charge is 36 cents per therm, and with delivery charges the all-in price is closer to a dollar. A 22 kW unit burns roughly 2 to 3 therms per hour under load, so an hour of heavy use costs about $2 to $3.

The generator doesn't work that hard all day. Overnight, with the house quiet, it sips fuel. The weekly self test runs a few minutes and costs pennies. There's no tank to fill and no gas cans in the garage, because the fuel comes straight from your gas service.

Budget for upkeep too. Annual service runs $200 to $650 per year and covers oil, filters, plugs, and a load test. A maintenance plan keeps the warranty valid and catches small problems before an outage finds them for you.

Do You Need a Permit to Install a Generator in Illinois?

Yes. Every North Shore village requires electrical and gas permits plus inspections for a standby generator. Combined fees typically run $80 to $450. The Village of Northbrook, for example, lists a $90 electrical and gas fee for a residential generator install. Your installer should pull the permits, not you.

Each village also enforces placement rules based on national standards like NFPA 37, which govern how far the unit must sit from windows, doors, and property lines. Several villages updated their fee schedules in mid 2026, so treat any fee you read online as a starting point and check the current schedule. Permits are also the slowest step, which is why the full project takes weeks even though the on-site work takes a day or two. For the full walkthrough, including NFPA 37 setback rules and village requirements, see our Illinois generator permit guide.

Is a Whole House Generator Worth the Money?

For many North Shore homes, yes. More than 300,000 ComEd customers lost power in the July 2026 storms, and some waited days for restoration. One flooded finished basement, from a sump pump sitting dead in an outage, can cost more than the generator that would have kept it running.

The math has three parts. First, prevented losses: spoiled food, hotel nights, lost work days, and water damage. Second, home value: HomeGuide, citing Consumer Reports data, estimates a standby generator can raise home value by about 5 percent. On a typical North Shore home price, that exceeds the cost of the install. Third, the part with no price tag: heat in January, air conditioning in July, and a sump pump that never stops.

Outages here aren't rare events. Tree heavy streets and aging overhead lines make parts of the North Shore some of the most outage prone territory in the ComEd service area. Our explainer covers why the North Shore loses power so often if you want the full picture. And if you are still weighing a cheaper portable unit against a full standby install, our standby vs. portable generator comparison breaks down what each one can actually run. If a battery system is also on your list, our generator vs. battery backup comparison breaks down runtime, cost, and rebates side by side. For the full breakdown on home value, insurance discounts, and the basement flood math, see our guide on whether a whole house generator is worth it.

Frequently Asked Questions

How much does a whole house generator cost for a 2,500 square foot house in Illinois?

Most 2,500 square foot homes need a 20 to 22 kW unit and land between $12,000 and $14,000 installed. A short gas run and an easy panel connection bring that down. A long trench or a gas meter upgrade pushes it higher.

How much does it cost to run a whole house generator per day?

Plan on $30 to $60 in natural gas for a full day of outage coverage. As of July 2026, the Nicor Gas supply charge is 36 cents per therm, and a 22 kW unit burns roughly 2 to 3 therms per hour under load.

Do you need a permit to install a standby generator in Illinois?

Yes. North Shore villages require electrical and gas permits plus inspections. Combined fees typically run $80 to $450. Northbrook, for example, lists a $90 electrical and gas fee for a residential generator install. Your installer should pull the permits for you.

Does a whole house generator increase home value?

Yes. HomeGuide, citing Consumer Reports data, estimates a standby generator can raise home value by about 5 percent. In outage prone areas like the North Shore, backup power can also help a home sell faster.

How long does generator installation take?

Expect 4 to 8 weeks from signed contract to a running generator. Permits and utility coordination take most of that time. The on-site work usually takes one to two days.

Is a battery backup cheaper than a whole house generator?

Sometimes upfront, but a battery stores a limited number of hours. A whole home battery like FranklinWH handles short outages well and pairs with solar. For multi-day outages like July 2026, a natural gas generator keeps running as long as the outage lasts.

Get a Real Number for Your Home

The ranges in this guide are honest, but your house sets the real price. The gas meter location, the panel, the lot, and the unit size all matter, and no article can measure your side yard.

A quote costs nothing. Fill out the form and we'll send your request to one licensed and insured local electrician who installs on the North Shore every week. You'll get a real number for your exact home, not a national average. Request your quote here and have it in hand before the next storm shows up.