A new HVAC system in Illinois costs between $7,100 and $14,200 in 2026, with the average homeowner paying about $9,600 for a complete AC and furnace replacement. That's roughly 16% above the national average — driven primarily by the Chicago metro area's higher labor rates and permit costs. Downstate Illinois is actually quite affordable, often matching or beating national averages.
Illinois is a true four-season HVAC state. You need a robust furnace for winters that regularly hit single digits and below zero, and a properly sized AC for summers that push into the 90s with high humidity. This guide breaks down costs for every region and equipment type so you can budget accurately.
Illinois HVAC Costs at a Glance
Illinois is a furnace-first state. Over 80% of Illinois homes use natural gas furnaces as their primary heating source. Gas is cheap here (averaging $1.05/therm), making gas furnaces very economical to operate. Heat pumps are gaining ground but the installed base remains overwhelmingly gas.
The Chicago vs. Downstate Price Gap
The single most important factor in Illinois HVAC pricing is whether you're in the Chicago metro area or downstate. The difference is dramatic:
Why Chicago Is More Expensive
City of Chicago permits and inspections are the primary cost escalator. Chicago requires a mechanical permit for all HVAC work, a plan review for new installations (not always required for replacements), and an inspection. The permit process in Chicago can take 1–3 weeks.
Union influence. While HVAC work in private homes doesn't require union labor, the strong union presence in the Chicago construction market pushes all wages upward. Non-union contractors in Chicago still pay more than their downstate counterparts to attract and retain qualified technicians.
Cost of living. Chicago-area overhead — rent, insurance, vehicle costs, fuel — is significantly higher. Contractors pass these costs through to customers.
Older housing stock. Chicago has a large inventory of pre-1950 homes with challenging HVAC access. Basements are cramped, ductwork routes are complicated, and older homes often need additional work (electrical upgrades, duct modifications) beyond basic equipment replacement.
HVAC Costs by Illinois Region
City of Chicago
Climate: Cold winters (avg. 22°F January, with windchill frequently below 0°F), warm humid summers (avg. 84°F July with 65%+ humidity).
Typical system: 80,000–100,000 BTU gas furnace + 2.5–3.5 ton AC
Average full system cost: $11,000–$15,500
Chicago's HVAC market is large and competitive, with hundreds of contractors. However, the regulatory environment, older building stock, and premium labor rates keep costs well above state and national averages.
Example: Lincoln Park, Chicago — 1,800 sq ft vintage two-flat (owner's unit). Replacing a 25-year-old 80,000 BTU furnace and adding a 2.5-ton central AC to existing ductwork. Carrier 16 SEER2 AC + 96% two-stage furnace. Equipment: $5,200. Labor: $4,200. Materials and fittings: $800. Chicago permit: $450. Duct modifications: $1,200. Total: $11,850.
Example: Beverly neighborhood, Chicago — 2,200 sq ft bungalow. Full HVAC replacement: 3.5-ton Trane 17 SEER2 AC + 100,000 BTU 96% variable-speed furnace. Equipment: $6,200. Labor: $4,600. Materials: $750. Permits: $500. Duct cleaning and sealing: $800. Total: $12,850.
Chicago Suburbs (Cook, DuPage, Lake, Will, Kane Counties)
Climate: Same as Chicago, slightly colder in far western and northern suburbs.
Typical system: 80,000–100,000 BTU gas furnace + 3–4 ton AC
Average full system cost: $9,500–$14,000
Suburban Chicago pricing is slightly lower than the city proper. Permit processes are simpler, access is easier, and there's strong contractor competition. The far western suburbs (Kane, Kendall counties) tend to be the most affordable, while the North Shore (Winnetka, Glencoe, Lake Forest) commands premium pricing due to an affluent customer base expecting top-tier service.
Example: Naperville, IL — 2,400 sq ft two-story. Replacing a 17-year-old system with a Lennox 18 SEER2 AC + 96% modulating furnace. Equipment: $7,000. Labor: $3,400. Materials: $700. Permits: $300. Total: $11,400.
Springfield / Central Illinois
Climate: True four-season. Cold winters (avg. 25°F January), hot humid summers (avg. 87°F July).
Typical system: 80,000 BTU gas furnace + 3-ton AC
Average full system cost: $7,500–$11,000
Central Illinois offers pricing close to the national average. Moderate labor rates, reasonable permits, and good contractor competition keep costs in check.
Example: Springfield, IL — 2,000 sq ft ranch. Standard replacement with Rheem 16 SEER2 AC + 80,000 BTU 96% furnace. Equipment: $4,400. Labor: $2,200. Materials: $500. Permits: $150. Total: $7,250.
Southern Illinois (Carbondale, Marion, Metro East)
Climate: Milder winters than Chicago (avg. 30°F January), hot humid summers.
Typical system: 60,000–80,000 BTU gas furnace + 3–3.5 ton AC
Average full system cost: $7,100–$10,500
Southern Illinois is the most affordable region in the state. Lower labor rates, lower cost of living, and milder winters (smaller heating equipment needed) all contribute. The Metro East area (Belleville, Edwardsville, O'Fallon) near St. Louis has slightly higher pricing than deeper southern Illinois.
Example: Belleville, IL — 1,600 sq ft home. Replacing a 3-ton system with a Goodman 16 SEER2 AC + 60,000 BTU 96% furnace. Equipment: $3,800. Labor: $1,800. Materials: $450. Permits: $100. Total: $6,150.
Illinois Furnace Guide: What You Need to Know
Since over 80% of Illinois homes heat with gas, furnace selection is critical. Here's your guide:
AFUE Rating: What Efficiency Do You Need?
*Based on 2,000 sq ft Chicago home using ~1,000 therms/year at $1.05/therm average.
For Illinois: 96% AFUE two-stage furnaces offer the best value. The jump from 80% to 96% saves about $208/year in gas costs. Over 15 years, that's $3,120 in savings — easily offsetting the $800–$1,500 equipment premium. Two-stage operation also provides better comfort (less temperature swing, quieter operation). The jump from 96% to 98% modulating saves only ~$22/year more and rarely justifies the $700–$1,500 additional cost.
Furnace Sizing for Illinois
Illinois homes need more heating capacity than cooling capacity. Here's typical sizing:
Heat Pumps in Illinois: Growing but Niche
Heat pumps represent a small but growing share of the Illinois HVAC market. Here's the current state of play:
The case for heat pumps in Illinois: Cold-climate heat pumps now work effectively down to -13°F to -22°F, covering all but the most extreme Illinois cold snaps. They provide both heating and cooling from a single system. Federal tax credits ($2,000) and utility rebates make them cost-competitive with traditional AC + furnace combos.
The case for sticking with gas: Illinois natural gas is cheap ($1.05/therm average). Illinois electricity is moderate (16.5¢/kWh). At current rates, a gas furnace costs about 20–30% less to operate per heating season than an air-source heat pump in northern Illinois. The economic advantage of heat pumps is weaker in Illinois than in states with expensive gas or cheap electricity.
The best compromise: dual fuel. A dual-fuel system pairs a heat pump with a gas furnace. The heat pump handles heating when temperatures are above 30–35°F (where it's more efficient than gas), and the furnace takes over during extreme cold. This gives you the lowest total operating cost in Illinois's climate.
Dual-fuel wins on economics in Illinois. It's the cheapest system to operate by $160–$430/year. The upfront cost ($12,500–$18,000) is higher than AC + furnace ($9,600–$14,200), but the $2,000 federal tax credit and $162+/year fuel savings close the gap. Payback period: 5–9 years.
Illinois HVAC Rebates and Incentives for 2026
Federal Incentives
- 25C Tax Credit: Up to $2,000 for qualifying heat pumps; up to $600 for AC or furnace
- HEEHRA: Up to $8,000 for income-qualified heat pump installations
ComEd Rebates (Northern Illinois)
ComEd serves most of northern Illinois including Chicago and suburbs:
- Central AC: $100–$300 for qualifying 16+ SEER2 units
- Heat Pumps: $300–$1,000 for qualifying units
- Smart Thermostat: $100
- Duct Sealing: $200–$400
- Whole-Home Energy Assessment: Free or discounted through ComEd's Energy Efficiency Program
Ameren Illinois Rebates (Central and Southern IL)
Ameren serves central and southern Illinois:
- Central AC: $100–$250 for qualifying units
- Heat Pumps: $250–$800 for qualifying units
- Smart Thermostat: $100
- Gas Furnace: $100–$200 for 96%+ AFUE
- Duct Sealing: $150–$300
Nicor Gas Rebates (Northern IL Gas Customers)
- High-Efficiency Furnace: $200–$400 for 97%+ AFUE
- Smart Thermostat: $100
- Boiler: $200–$300 for high-efficiency replacement
- Home Energy Assessment: Free through Nicor's energy efficiency program
Stack ComEd and Nicor rebates. In northern Illinois, most homeowners have ComEd for electricity and Nicor for gas. You can claim rebates from both utilities on a single HVAC project, plus the federal tax credit. A dual-fuel heat pump system with a high-efficiency gas furnace backup could yield $200–$400 (Nicor for furnace) + $300–$1,000 (ComEd for heat pump) + $2,000 (federal tax credit) = $2,500–$3,400 in combined incentives.
Seasonal Pricing in Illinois
Illinois has distinct HVAC pricing seasons:
Summer peak (June–August): AC demand highest. Emergency replacements command 10–20% premiums. Contractors booked 1–3 weeks out.
Fall heating rush (September–November): Furnace demand spikes as homeowners prepare for winter. The October–November window is especially busy. Prices moderate but availability is tight.
Winter bargains (December–February): Best pricing of the year. Contractor demand drops to its lowest. Many offer winter specials with 10–20% discounts. Don't worry about installing a furnace in January — contractors do this every day and it takes just 4–8 hours.
Spring shoulder (March–May): Moderate pricing. Good availability. Solid window for planned replacements before summer.
Key Takeaways
- Illinois HVAC installation averages $9,600, about 16% above the national average
- Chicago metro ($10,800–$15,500) costs 40–50% more than downstate ($7,100–$11,000)
- Over 80% of Illinois homes use gas furnaces — gas is cheap here at $1.05/therm
- 96% AFUE two-stage furnaces offer the best value for Illinois heating
- Dual-fuel systems (heat pump + gas furnace) provide the lowest operating cost
- Federal tax credit ($2,000) + ComEd/Ameren + Nicor rebates can offset $2,500–$3,400+
- December–February offers the best HVAC pricing and shortest wait times
- Always verify contractor licensing and get 3+ itemized quotes
Frequently Asked Questions
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