HVAC system replacement in Nashville means swapping the outdoor unit, the indoor coil and the furnace or air handler as one matched set, sized by a Manual J load calculation instead of the old unit's tonnage. You choose gas heat, a heat pump or dual fuel, and we price each option before work starts. Call (615) 412-2815 at any hour.
What gets replaced and how the new system is sized
Replacing a whole system is a sizing job before it's an equipment job. We measure the house, test the ductwork for size and leakage, and run a load calculation. The old unit's tonnage is only a clue, because many houses have gained insulation or new windows since it went in.
Then we match the outdoor unit, indoor coil and furnace or air handler so the rated efficiency is real. New equipment uses a newer refrigerant than R-22 and R-410A systems, so a new condenser cannot run on an old coil.
Full split system replacement
This is the most common setup around Nashville: a condenser outside and a gas or electric furnace inside with the cooling coil on top. When the condenser still runs R-22, or the furnace heat exchanger shows wear, replacing only one half leaves a mismatched pair that never reaches its rated efficiency.
Replacing both lets us install the coil, furnace blower and condenser as a tested combination. HomeGuide lists $5,000 to $11,000 for an AC and furnace together. The work also covers refrigerant recovery, the line set, a new pad and a fresh condensate trap.
Heat pump and air handler sets
Homes without gas service usually heat with a heat pump and an air handler that carries backup electric heat strips. When that pair wears out, the replacement is another matched set, often with a variable-speed blower that pulls more moisture out of a humid July.
We size the heat strips for the coldest nights so the backup doesn't trip breakers or leave the house short. The thermostat matters too, since a heat pump needs one that stages the strips correctly instead of firing them every time the setting moves a degree. HomeGuide lists heat pump installation at $3,800 to $8,200.
Load calculations
An oversized system cools the air fast, shuts off and leaves the house clammy, because it never runs long enough to pull out moisture. An undersized one runs all afternoon and still loses ground on the hottest days.
A Manual J load calculation works room by room: wall and attic insulation, window area and direction, air leakage and how many people live there. Manual S then picks equipment that fits that load. We also measure static pressure in the ductwork, since a new system on undersized ducts will be loud and short on airflow no matter how well it's sized.
Gas, heat pump or dual fuel: which replacement fits
| Option | Gas furnace and AC | Heat pump and air handler | Dual fuel |
|---|---|---|---|
| Heat source | Burns natural gas or propane | Moves heat with electricity, strips as backup | Heat pump first, gas furnace on cold nights |
| Needs gas service | Yes | No | Yes |
| Cooling | Separate AC condenser | Same outdoor unit cools and heats | Same outdoor unit cools and heats |
| Usual fit | Homes with gas already piped | All-electric homes | Homes with gas that want electric heat most of the winter |
What drives the price of a full system replacement
The range is wide because the system type and the condition of the ductwork move the total more than anything else.
For planning, HomeGuide puts typical national pricing for this kind of job at $5,000 to $11,000 for an AC and furnace together (HomeGuide, August 2025). That is a market range, not our quote; the figure for your home comes after we see the equipment.
- Fuel and system type. Gas furnace with AC, heat pump with air handler, and dual fuel each carry different equipment and wiring costs.
- Efficiency and staging. Two-stage and variable-speed equipment costs more up front and runs quieter with better humidity control.
- Ductwork condition. Leaky or undersized ducts may need sealing, resizing or partial replacement to work with new equipment.
- Indoor unit location. Attic and crawl space installs take more labor than a basement or a hall closet.
- Electrical and line set. A new disconnect, a breaker change or a new line set adds to the base equipment price.
Where Nashville housing ages line up with replacement
Madison was built mostly from the 1950s through the 1980s, peaking in the 1960s, so a house there may be on its third system while still running ductwork sized for the first. Antioch went up mostly from 1980 to 2019, peaking in the 2000s, and many systems installed in that boom are reaching the end of a normal service life. Storms set the timing too. The March 3, 2020 EF-3 tornado crossed East Nashville and Donelson, and a condenser hit by debris usually means replacing the matched set rather than one part.
What a full replacement includes
- Manual J load calculation and duct static pressure test
- Refrigerant recovery and removal of the old equipment
- Matched outdoor unit, coil and furnace or air handler
- Line set flush or replacement, new pad and disconnect
- Condensate line, trap and overflow float switch
- Startup charge check, airflow test and thermostat setup
From load calculation to the first full cycle
- 1
Measure the house
We run the load calculation and test duct static pressure before recommending a size.
- 2
Price the options
You see gas, heat pump and dual fuel side by side, along with any ductwork each one needs.
- 3
Remove and set
Old refrigerant is recovered, the old equipment comes out and the new matched set goes in.
- 4
Commission it
We pressure test, evacuate, charge to the manufacturer target and check airflow and temperature split.
How long a system replacement takes
A like-for-like split system swap with the indoor unit in a basement or closet usually takes one full day, with commissioning running into the afternoon.
Plan on a second day when the indoor unit sits in a tight attic or crawl space, when ductwork is being resized, or when a gas home moves to a heat pump and needs new wiring.
Brands we work on
We service and install equipment from the major manufacturers, including Carrier, Trane, Lennox, Rheem, Goodman, American Standard, Daikin, Mitsubishi Electric, Bryant, Ruud, York and Amana.
Replacement questions Nashville homeowners ask
Not always. If the furnace is sound and its blower can move enough air for the new coil, we can replace only the cooling side, but the new coil must match the new condenser.
A Manual J load calculation answers that. The old unit size is only a clue, because insulation, windows and duct changes over the years shift the load.
For most homes, yes, with backup heat strips or a gas furnace in a dual fuel setup carrying the coldest nights.
If it uses R-22, needs a major part or keeps running up the bills, replacing it on your schedule beats replacing it during a heat wave.
Yes. The phone is answered 24 hours a day, every day.