Furnace Replacement Cost in Mount Prospect, Illinois
Our 2026 estimate for furnace replacement in Mount Prospect, IL is $4,200 to $10,200. That puts Mount Prospect 31% above the national average, mainly because of higher incomes and home values, which push labor rates up and the bigger heating equipment this climate calls for.
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Mount Prospect Weather and HVAC Load
In a normal year, Mount Prospect racks up 6,085 heating and 933 cooling degree days (NOAA 1991-2020 normals). Heating is the bigger job here, and furnaces and heat pumps in Mount Prospect put in far more hours than the air conditioner. A normal year brings 122 nights at or below freezing and 17 days over 90°F. Snowfall averages about 38 inches. For a 2,000 sq ft house, this climate points to a heating load somewhere near 65,000 BTU/h. Treat that as a starting number. A Manual J calculation will move it up or down based on insulation and windows.
| Heating degree days / year | 6,085 |
|---|---|
| Cooling degree days / year | 933 |
| Nights at or below 32°F | 122 |
| Days above 90°F | 17 |
| Average low / high | 42.3°F / 59.2°F |
Mount Prospect Housing Stock
Census figures put the median build year in Mount Prospect at 1969, so a typical house here has about 57 years on it. A lot of these homes are on their second or third system by now. The ductwork is usually original, and leaky joints are common. Mount Prospect has roughly 15,000 owner-occupied homes, or 70% of households. The median home value is $377,000, and median household income is $103,911. We use both figures to adjust labor and pricing for this page.
NOAA storm reports for Cook County show 27 hail days and 75 days with damaging thunderstorm winds over the six years from 2020 to 2025. The largest hail reported was 2.75 inches across. Hail flattens the thin aluminum fins on condenser coils and cuts airflow. After a big storm, take a look at the outdoor unit; homeowners insurance often covers the damage. Cook County also had 8 tornado days in that period. In Mount Prospect, 18.3% of residents are 65 or older. For older adults, a house with no heat in January or no AC during a heat wave is a medical risk. Mention it when you call, since many companies put those calls first.
When Replacement Makes Sense
- Some rooms stay cold, the burner short-cycles, or the ignitor keeps failing
- A repair quote runs past a third of the cost of a new unit
- The furnace is 15 to 20 years old or more
- Gas or electric bills keep climbing even though usage hasn't changed
What Moves the Price
- AFUE rating: a basic 80% unit vs. a 96% condensing furnace
- BTU size, which should come from a Manual J load calculation
- Permit and inspection fees, which the local building department sets
- Condition of the existing ductwork and any changes it needs
- Single-stage, two-stage or modulating gas valve
- New PVC venting if you move to a condensing model
We raised the national figures about 31% for Mount Prospect using local income, home values and the equipment size this climate needs. Real bids can still come in outside the range, so collect three written quotes.
What the Quote Should Cover
- The permit and the manufacturer warranty registration
- Removing and hauling away the old furnace
- Gas line and vent connections
- Combustion and safety tests
- The new furnace, filter rack and thermostat wiring
Illinois Permits, Efficiency Rules and Rebates
Illinois falls in the DOE's North region. New split central air conditioners must meet at least 13.4 SEER2, and heat pumps sold anywhere in the U.S. need 14.3 SEER2 and 7.5 HSPF2. Equipment replacements in Mount Prospect generally need a mechanical permit, and a reputable contractor will pull it for you. Ask for their Illinois license or registration number and a certificate of insurance with the quote. The federal 25C tax credit ended for equipment installed after December 31, 2025, so incentives now come mostly from utilities and state programs. Check your electric and gas utility's rebate page before you pick equipment.
Before You Hire
- Look up utility rebates on 95%+ AFUE units before you buy.
- Ask for the Manual J load calculation in writing. Oversized furnaces are the most common mistake we see.
- Make sure all three quotes are for the same AFUE and staging, or you can't compare them.
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Furnace Replacement Questions from Mount Prospect Homeowners
How much is furnace replacement in Mount Prospect?
Plan on $4,200 to $10,200, with most jobs near $7,500. Equipment efficiency, house size and the condition of the ducts and wiring decide where your quote falls.
When is the best time to schedule furnace replacement in Mount Prospect?
Between late spring and early fall. Mount Prospect averages 122 freezing nights a year, and heating calls spike from November through February.
Is a high-efficiency furnace worth it?
In cold climates, a 95%+ AFUE furnace usually earns back the price difference in lower gas bills. Where winters are mild, the payback can take a very long time.
How long does a furnace replacement take?
A straight swap is usually done in one day, somewhere between 4 and 10 hours. Moving to a condensing furnace with new PVC venting can add a few more.
Furnace Replacement Near Mount Prospect
- Des Plaines $3,900 to $9,600
- Arlington Heights $4,400 to $10,800
- Oak Lawn $3,700 to $8,900
- Berwyn $3,600 to $8,800
- Orland Park $4,100 to $9,900
- Tinley Park $4,100 to $9,900
- Wheaton $4,500 to $11,000
- Skokie $4,100 to $10,000
Sources: U.S. Census Bureau ACS 5-year estimates 2019-2023 and 2024 population estimates; NOAA NCEI U.S. Climate Normals 1991-2020, station Chicago Palwaukee Airport; NOAA Storm Events Database 2020-2025, Cook County. Prices are our estimates, not contractor quotes. Updated 2026.