HVAC System Replacement Cost in Knoxville, Tennessee
Expect to pay $7,800 to $17,000 for full HVAC system replacement in Knoxville, TN. Most homeowners end up near $12,900, depending on the equipment tier and how much of the old setup can be reused.
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Knoxville Weather and HVAC Load
NOAA's 1991-2020 climate normals put Knoxville at 3,911 heating degree days and 1,363 cooling degree days per year. Heating is the bigger job here, and furnaces and heat pumps in Knoxville put in far more hours than the air conditioner. Count on roughly 87 nights below 32°F and 36 afternoons past 90°F in a typical year. Snowfall averages about 5 inches. For a 2,000 sq ft house, this climate points to a heating load somewhere near 50,000 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 | 3,911 |
|---|---|
| Cooling degree days / year | 1,363 |
| Nights at or below 32°F | 87 |
| Days above 90°F | 36 |
| Average low / high | 45.9°F / 70°F |
Knoxville Housing Stock
Census figures put the median build year in Knoxville at 1974, so a typical house here has about 52 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. Knoxville has roughly 40,000 owner-occupied homes, or 46.6% of households. The median home value is $214,000, and median household income is $50,994. We use both figures to adjust labor and pricing for this page.
Knox County had 12 hail days and 54 days with damaging thunderstorm winds from 2020 through 2025, according to NOAA storm records. The largest hail reported was 1.75 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.
When Replacement Makes Sense
- Both the heating and cooling equipment are 15 years old or more
- Both units keep needing repairs
- Some rooms are uncomfortable, and the energy bills are high
What Moves the Price
- Furnace plus AC, or heat pump plus air handler
- Thermostat and zoning upgrades
- Equipment sized to the house and climate
- Efficiency ratings: SEER2, AFUE and HSPF2
- Permits and electrical work
- Duct repair or replacement
We lowered the national figures about 8% for Knoxville 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
- Duct connections and sealing
- A load calculation and system design
- Removing the old equipment
- Startup, testing and warranty registration
- New, matched heating and cooling equipment
Tennessee Permits, Efficiency Rules and Rebates
Tennessee is in the DOE's Southeast region, where new split central air conditioners need at least 14.3 SEER2 (13.8 SEER2 for systems of 45,000 BTU/h and up). Expect the contractor to pull a mechanical permit for a replacement job in Knoxville. If a bidder suggests skipping it, move on. Also ask for a Tennessee license or registration number and proof of insurance. 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
- Get one quote for a heat pump system and one for a furnace plus AC.
- Ask for a duct leakage test. Leaky ducts can lose 20 to 30% of what the system puts out.
- Make every bidder quote the same efficiency ratings, or the prices won't compare.
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HVAC System Replacement Questions from Knoxville Homeowners
How much is full HVAC system replacement in Knoxville?
Plan on $7,800 to $17,000, with most jobs near $12,900. Equipment efficiency, house size and the condition of the ducts and wiring decide where your quote falls.
When is the best time to schedule full HVAC system replacement in Knoxville?
Between late spring and early fall. Knoxville averages 87 freezing nights a year, and heating calls spike from November through February.
How often should an HVAC system be replaced?
Most systems get replaced every 15 to 20 years. AC units and heat pumps usually wear out before gas furnaces do.
Can I replace only the AC and keep my furnace?
Yes, as long as the indoor coil and blower work with the new AC. A mismatched system loses efficiency and can void the warranty.
HVAC System Replacement Near Knoxville
- Memphis $7,800 to $17,000
- Chattanooga $8,300 to $18,000
- Nashville $9,100 to $19,900
- Clarksville $8,300 to $18,100
Sources: U.S. Census Bureau ACS 5-year estimates 2019-2023 and 2024 population estimates; NOAA NCEI U.S. Climate Normals 1991-2020, station Knoxville Experiment Station; NOAA Storm Events Database 2020-2025, Knox County. Prices are our estimates, not contractor quotes. Updated 2026.