AC Installation Cost in Mount Prospect, Illinois
Expect to pay $4,500 to $10,200 for new AC installation in Mount Prospect, IL. Most homeowners end up near $7,600, depending on the equipment tier and how much of the old setup can be reused.
Compare Free Quotes in Mount Prospect
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. The AC still runs every summer, but it works far fewer hours than the furnace does. A normal year brings 122 nights at or below freezing and 17 days over 90°F. Snowfall averages about 38 inches. On the cooling side, a 2,000 sq ft house here usually needs around 3 tons. A tight, well-insulated house may get by with half a ton less.
| 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 It Makes Sense
- The house can't reach the thermostat setting on hot afternoons
- It still runs on R-22 refrigerant
- The AC is 12 to 15 years old or more
- It has had more than one refrigerant leak
What Moves the Price
- SEER2 rating and whether the compressor is single-stage or variable-speed
- Electrical work such as a new disconnect, breaker or wiring
- Tonnage, based on house size and local climate
- Whether the coil and line set also need replacing
- The pad, permit and refrigerant (R-410A or the newer R-454B)
We raised the national figures about 7% 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
- Startup, an airflow check and warranty registration
- Removing the old condenser and coil
- Refrigerant charge and a leak test
- The electrical disconnect and wiring
- The new condenser, coil and, if needed, line set
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
- Ask what federal, state or utility incentives apply to the model you're quoted.
- Ask for a Manual J calculation. "Same size as the old one" isn't sizing.
- Buy the condenser and coil as a matched set, or you may void the manufacturer warranty.
Get Free AC Installation Quotes in Mount Prospect
Tell us where you are and up to three licensed local pros will get in touch. You don't have to hire any of them.
AC Installation Questions from Mount Prospect Homeowners
How much is new AC installation in Mount Prospect?
Plan on $4,500 to $10,200, with most jobs near $7,600. Equipment efficiency, house size and the condition of the ducts and wiring decide where your quote falls.
When is the best time to schedule new AC installation 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.
How long does a new AC last?
With yearly maintenance, 12 to 17 years. Salt air and extreme heat shorten that.
What size AC do I need?
It depends on square footage, insulation, windows and climate. The rough rule is a ton for every 450 to 650 sq ft, but only a Manual J calculation gives you a real number.
AC Installation Near Mount Prospect
- Des Plaines $4,300 to $9,700
- Arlington Heights $4,700 to $10,700
- Oak Lawn $4,100 to $9,300
- Berwyn $4,000 to $9,100
- Orland Park $4,500 to $10,100
- Tinley Park $4,300 to $9,700
- Wheaton $4,800 to $11,000
- Skokie $4,300 to $9,700
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.