• Largest cities
• Local notes
• Models & pricing
• Which model
• FAQs
• Get a quote

Largest cities we serve in McHenry County, IL

McHenry County counted 310,229 residents in the 2020 Census and 317,751 in the Census Bureau’s July 1, 2025 estimate, spread over 603 square miles, with an owner-occupied housing rate of 82.7 percent (2020-2024 American Community Survey). The table lists the twelve largest cities and villages that are wholly or partly in the county. Populations are the 2020 U.S. Census counts as published on the Wikipedia municipality table for McHenry County and checked against each community’s own article. Distances are driving miles from our Woodstock headquarters, which serves every community in this county, measured with OpenStreetMap routing from the office to the approximate center of each community and rounded to the nearest mile; the mileage to your own address will differ a little. Five of the twelve extend across a county line into Kane County or Lake County, and we serve the whole village either way.

Installing a KOHLER generator in McHenry County, IL

Natural gas: Nicor Gas and the meter check

Natural gas in McHenry County comes from Nicor Gas (Northern Illinois Gas Company). Nicor’s tariff on file with the Illinois Commerce Commission names the McHenry County cities and villages it serves, including all eleven of the other communities in the table above (Fox Lake is listed under Lake County in the same filing), and states that its rates apply within those municipal limits and the unincorporated territory contiguous to them. The tariff does not say a gas main runs past every rural property, so if you live outside a town our first question is whether your street actually has Nicor service. Where it does, our gas-line technician sizes the run and checks the existing meter against the generator’s full-load demand, which is 179,000 BTU per hour for the 10RESV and 290,000 BTU per hour for the 26RCA, on top of whatever furnace, water heater and range are already on the meter; a meter upgrade by Nicor is sometimes needed, and we coordinate it. Where there is no main, all five KOHLER models run on propane and are field-convertible, so a rural home is not shut out of a standby generator.

Electric service: ComEd and the transfer switch

Electric service in McHenry County is ComEd (Commonwealth Edison), whose service-territory filing with the Illinois Commerce Commission covers the county. The automatic transfer switch goes between the ComEd meter and your panel, and that is where the county’s electrical code matters. McHenry County has adopted the 2020 National Electrical Code with local amendments that require a permit through the Planning & Development Department before any wiring or equipment associated with an electrical service is installed, replaced or modified, require rough inspections before anything is covered or concealed, and require a Service Inspection, after which the building official issues written notification authorizing the electric utility to energize the system. For an unincorporated address that means the transfer switch tie-in is inspected before it is closed up and ComEd is not asked to energize until the county signs off; we schedule both. Whole-house installs on a 200 A service typically use a service-entrance-rated transfer switch, and an RXT transfer switch with load management is how the 26RCA carries two air conditioners and the 12RESV carries one.

Who issues the permit

Which office issues your permit depends on which side of a municipal boundary you live on. In unincorporated McHenry County the McHenry County Department of Planning & Development, Building Division reviews construction documents, issues building permits and inspects all construction activity; it says it strives to complete reviews within 10 business days of the application date and rejects incomplete applications. Applications go through the county’s online permit portal (paper applications have not been accepted since the end of January 2025) and are reviewed against the 2021 ICC codes and the 2020 NEC. The county lists “Residential Service Upgrade” among its residential permit types but no generator-specific type, so the requirement for a generator and transfer switch follows from the electrical-service rules above; the department can confirm at (815) 334-4560. Inside city or village limits the permit comes from that municipality’s building department instead. Either way, GSHA prepares and submits the application, includes the permit in the installed price and meets the inspectors; most installs take one to two days on site once the permit is issued.

Groundwater, wells and septic systems

The McHenry County Department of Health states that the county is 100 percent dependent on groundwater for its drinking water, and the county’s Water Resources Action Plan says the same: every home here, on a municipal system or a private well, drinks groundwater. For a home on its own well that matters for sizing, because the Health Department’s description of a standard residential drilled well includes a submersible pump, a pressure switch and an electrical control box, and the well pump has to be in the generator’s load calculation or the house has no water during an outage. The 10RESV we install covers a well pump alongside the furnace, refrigerator, sump pump and lights, and we size the 26RCA for a well pump plus two air conditioners on load management and an electric range. The county pages we checked do not give the share of homes on private wells, so we confirm it at the estimate. Septic systems are the other rural consideration: the Health Department requires its own permit to install, modify, repair or replace a septic system, the work must be done by an Illinois Department of Public Health licensed septic contractor, and aerobic treatment units are allowed only when they discharge to a compliant subsurface seepage system. We locate the tank and field before placing the generator pad or trenching the gas and electrical lines so the septic system is left untouched.

Fox River and Chain O’Lakes flood risk

The county’s Flood Information Headquarters page says parts of McHenry County, especially along the Fox River and Chain O’Lakes, are susceptible to flooding during major storm events. For riverfront and lakefront homes that shapes both placement and paperwork. The county’s Permit FAQs say most building permits require a stormwater review for impacts to wetlands, floodplains or floodways, with additional requirements if the building is in the floodplain, and the Water Resources Division says all development within a floodplain requires a Stormwater Management Permit under the county Stormwater Management Ordinance; the division can help you understand your flood risk at (815) 334-4560. In practice, placement starts with the highest practical spot on the lot, and if the parcel is mapped in a floodplain the stormwater permit becomes part of the job.

KOHLER models and installed pricing

About “installed from” prices. Every KOHLER generator is a custom installation. The “installed from” price is our starting package for that model (generator, standard automatic transfer switch, standard gas and electrical connections, permit handling and start-up). Your final price depends on generator placement, gas line size and length, electrical panel condition and local permit fees, so we confirm it with a free on-site estimate before any work begins. KOHLER’s published MSRP for the generator alone runs from $3,946 (10RESV) to $7,546 (26RCA).

Which KOHLER model fits homes in McHenry County

Which KOHLER model fits a McHenry County home

Two things set McHenry County apart when we size a generator: every home is on groundwater, so a private well pump is often on the load list, and the gas main may stop before a rural driveway, so propane has to stay on the table. All five KOHLER models we install run on natural gas or propane and are field-convertible, carry a 5-year/2,000-hour limited warranty covering parts, labor and travel (7- and 10-year extensions available), include the RDC2 controller with the KOHLER Energy Management app, are rated for 181 mph winds, and can sit 18 inches from the house under NFPA guidelines (local codes apply). A cold-weather kit is recommended below 32 F; ask about it at the estimate. Full specifications and installed pricing are on each product page, and our own technicians handle KOHLER service and maintenance after the install.

• KOHLER 10RESV, installed from $8,000: essentials only, meaning furnace, refrigerator, sump pump, well pump and lights. Its 30.6 x 28 inch steel enclosure suits the tight side yard of an in-town lot.
• KOHLER 12RESV, installed from $8,500: the same narrow footprint with enough capacity for essentials plus one air conditioner through load management.
• KOHLER 14RCA, installed from $9,000: entry whole-house power for a small or mid-size home; KOHLER rates it to start and run a 5-ton air conditioner, and it is off-grid rated.
• KOHLER 20RCA, installed from $10,500: whole-house coverage for most 2,500 to 4,500 square foot homes with one central air conditioner, with 41 kVA of motor-starting capacity.
• KOHLER 26RCA, installed from $12,000: the largest air-cooled KOHLER, for large homes with two air conditioners on load management, a well pump, an electric range and an EV charger.

McHenry County KOHLER FAQs

Which office sends the crew to a McHenry County job?

Our Woodstock headquarters at 1257 Cobblestone Way, in the county seat. Every community in the table is within about 24 driving miles of that office and nine of the twelve are within 15, so nothing in the county comes near the edge of our standard 50-mile service radius. Our Lake Bluff office covers Lake County, and the KOHLER service-area page lists the other counties the two offices reach.

Do I need a permit for a standby generator in unincorporated McHenry County?

Yes. The county’s electrical code requires a permit through the Planning & Development Department before wiring or equipment associated with an electrical service is installed, replaced or modified, and the Building Division issues permits and inspects all construction in unincorporated McHenry County through its online portal. GSHA pulls the permit and schedules the rough and Service Inspections; inside a city or village the permit comes from that municipality instead, and you can confirm your address with the county at (815) 334-4560.

Which gas utility do you coordinate with in McHenry County?

Nicor Gas, whose Illinois Commerce Commission tariff names the McHenry County cities and villages it serves and the unincorporated territory contiguous to them. We check your existing meter against the generator’s full-load gas demand and arrange a Nicor meter upgrade when one is needed; if your street has no gas main, every KOHLER model we install also runs on propane.

Is Harvard or Fox Lake inside your service area?

Yes. Harvard is about 15 driving miles from our Woodstock office and Fox Lake, on the Lake County line, is about 23, the farthest of the county’s twelve largest communities; both are well inside our standard 50-mile service radius.

How much does a KOHLER generator cost installed in McHenry County?

Installed from $8,000 for the 10RESV; the 26RCA, the largest air-cooled model, starts at $12,000 installed, and the 12RESV, 14RCA and 20RCA fall between. Each starting package includes the generator, a standard automatic transfer switch, standard gas and electrical connections, permits and start-up; because every installation is custom, we confirm the final price with a free on-site estimate.

Other county pages: Boone County · DuPage County · Kane County · Will County · Cook County · Lake County · full KOHLER service area

More: how installation works and what is included · service and maintenance · transfer switches and accessories · why KOHLER

Sources: McHenry County, Illinois (Wikipedia municipality table, 2020 Census populations) · Algonquin, Illinois (Wikipedia; McHenry and Kane counties) · Huntley, Illinois (Wikipedia; Kane and McHenry counties) · Cary, Illinois (Wikipedia; part of village in Cuba Township, Lake County) · Fox Lake, Illinois (Wikipedia; Lake and McHenry counties) · Island Lake, Illinois (Wikipedia; Lake and McHenry counties) · U.S. Census Bureau QuickFacts, McHenry County, Illinois · Driving distances: OpenStreetMap routing (OSRM table service) from the GSHA Woodstock office to the approximate center of each community, retrieved September 10, 2026 · GSHA Woodstock office coordinates: OpenStreetMap Nominatim geocode of 1257 Cobblestone Way, Woodstock, IL 60098 · Nicor Gas Ill.C.C. No. 16 tariff, municipalities and unincorporated contiguous territory served (28 McHenry County cities and villages plus unincorporated areas; ICC docket P2026-0099, document 659392) · ComEd electric service territory, ICC filing Part 285.305(a)(3) (county map and McHenry County community list) · McHenry County Planning & Development, Building Division · McHenry County Permit Resources (permit types, digital portal since January 2025, 2021 ICC codes and 2020 NEC, phone) · McHenry County Building Division Permit FAQs (stormwater review, floodplain) · McHenry County Code Chapter 15.12, Electrical (adopts NEC 2020 with local amendments; Ord. O-202211-10-050, passed November 15, 2022) · McHenry County Department of Health, Private Water Supply · McHenry County Water Resources Action Plan · McHenry County Department of Health, Onsite Wastewater Treatment (septic permits) · McHenry County Flood Information Headquarters · McHenry County Water Resources, Flooding and Flood Protection (Stormwater Management Permit in floodplains) · GSHA Services KOHLER authorized dealer site. Distances are approximate driving miles from the nearest GSHA office, rounded to the mile.

About GSHA Services, LTD

GSHA Services, LTD is a licensed and insured electrical, heating, cooling, plumbing and generator contractor and an authorized KOHLER generator dealer (listed on KOHLER’s dealer site). Offices: 1257 Cobblestone Way, Suite A, Woodstock, IL 60098 and 11 N Skokie Hwy, Suite 111C, Lake Bluff, IL 60044. Phone (224) 220-3660. Email info@gshaservices.com. We sell, install, service and repair KOHLER home standby generators across the northern Chicago suburbs and southeastern Wisconsin. Contact us · All service areas · Financing

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