HVAC Replacement Cost Calculator

Home size
1,800 sq ft
Efficiency
Ductwork
Where the furnace lives
Your ZIP code

Showing the national average. Enter your ZIP code for local cost estimates.

Low $7,175
Typical $8,750
High $10,850

National average

Recommended capacity: — tons A rule of thumb for a moderate climate, with the furnace sized at 24 thousand BTU a ton. A Manual J load calculation is the proper way to size both halves, and replacing everything at once is the moment to have one done.

Where these figures come from
  • Plumbing, heating and air-conditioning contractors, United States: $42.44/hour, August 2026 (BLS CES CES2023822003)
  • Condenser and coil, base unit: $1,418.00 per system (price recorded October 2026, not index-adjusted)
  • Condenser and coil, capacity: $590.00 per ton of capacity (price recorded October 2026, not index-adjusted)
  • Refrigerant line set: $10.36 per linear foot, benchmark observed October 2026, unchanged against BLS WPU102502 to the three months ending August 2026
  • Gas furnace, base unit (80% AFUE): $250.00 per furnace (price recorded October 2026, not index-adjusted)
  • Gas furnace, capacity (80% AFUE): $10.00 per thousand BTU (price recorded October 2026, not index-adjusted)
  • Venting, gas connection, thermostat and filter rack: $280.00 per furnace (price recorded October 2026, not index-adjusted)

HVAC Replacement costs $7,175 to $10,850 for a typical 1,800 sq ft job in 2026, against a national benchmark of $8,750. Labor runs 19.9 crew hours at $42.44 an hour. Enter a ZIP code to apply that area's measured wages for this work and its regional price level.

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What makes up the price

Labor $1,182 19.9 hours at $42.44/hour, 40% burden, 1.00x regional
Condenser and coil, base unit $1,418 1 system at $1,418.00 each
Condenser and coil, capacity $1,770 3 ton of capacity at $590.00 each
Refrigerant line set $259 25 linear foot at $10.36 each
Gas furnace, base unit (80% AFUE) $250 1 furnace at $250.00 each
Gas furnace, capacity (80% AFUE) $720 72 thousand BTU at $10.00 each
Venting, gas connection, thermostat and filter rack $280 1 furnace at $280.00 each
Permit, disposal, pad and fittings $600
Contractor overhead and profit $2,268 35% applied to the work above
Typical total $8,750 $7,175 to $10,850 depending on contractor

Cost by size

National averages, before any local adjustment. Computed from the same model as the calculator above, so the two always agree.

Home size Tons of cooling Typical Range
1,000 sq ft 1.5 $6,900 $5,675 to $8,575
1,450 sq ft 2.5 $8,125 $6,675 to $10,075
1,800 sq ft 3 $8,750 $7,175 to $10,850
2,450 sq ft 4 $9,975 $8,175 to $12,375
3,050 sq ft 5 $11,200 $9,175 to $13,875

What bundling actually saves

1,800 sq ft, 3 tons
Air conditioner on its own $6,375
Furnace on its own $2,875
The two separately $9,250
Both together $8,750

$500. That is the honest number, and it is less than the industry generally implies. It comes from one mechanical permit instead of two, one disposal run, one trip, the plenum opened once, and one commissioning visit — about three hours of overlapping labor and $200 of duplicated fixed costs.

The real arguments for doing both at once are not on the invoice:

And the argument against: if one unit has ten good years in it, $500 does not justify throwing it away. Replacing a working 8-year-old furnace to save $500 on the air conditioner is a bad trade.

What it costs

Standard High efficiency
1,200 sq ft (2 tons) $7,525 $9,750
1,800 sq ft (3 tons) $8,750 $11,125
2,400 sq ft (4 tons) $9,975 $12,500

And what moves it:

1,800 sq ft, standard
Existing ducts, furnace in a basement $8,750
Furnace in a closet $9,800
Furnace in an attic or crawl space $10,925
Some duct modification $10,050
All new ductwork $16,625

Standard means 14.3 SEER2 cooling and an 80% AFUE furnace — the code minimum on both sides and what most changeouts are.

Two things that force the decision

Sometimes you do not get to replace one at a time, and both reasons are worth understanding before a salesperson explains them.

The indoor coil has to match the condenser. The evaporator coil sits in the furnace's plenum, and it is part of the air conditioning system rather than the heating one. A new condenser on an old coil is a mismatched pair: it will not reach its rated efficiency, it may not reach its rated capacity, and most manufacturers will not warrant it. So an air conditioning replacement almost always includes the coil — and if the furnace is old, the coil is sitting on top of it, which is how one decision becomes two.

The refrigerant has changed. Equipment manufactured from 2025 uses R-454B or R-32 rather than R-410A, under the EPA rules phasing down high-global-warming refrigerants. These are not interchangeable: a 2026 condenser cannot be paired with an R-410A coil or line set charge. In practice:

When to replace one and not both

Typical life
Air conditioner or heat pump 12–15 years
Gas furnace 15–20 years, often more

Furnaces outlive air conditioners, which is why a house commonly needs a new condenser and has a perfectly good furnace. Replace just the air conditioner — and its coil — when:

Replace both when:

A good contractor will tell you which of these applies. One who quotes a full system without having looked at the furnace's heat exchanger or asked its age has not done the diagnosis.

80% or 96% on the furnace

This is the half of the efficiency decision that actually matters, and it is climate-dependent.

A 96% AFUE condensing furnace is a different machine from an 80%: it extracts enough heat from the exhaust that the flue gas condenses, so it vents in PVC through a wall rather than up the existing metal flue, and it produces condensate that has to reach a drain or a pump. That is three extra hours of work as well as a more expensive box.

Rough arithmetic: the step from 80% to 96% saves a sixth of the gas. On a $900 annual heating bill that is $150 a year, against about $2,375 more for high efficiency on both sides here — so it pays in a long cold heating season and does not in the South.

One trap: if the old 80% furnace shares a masonry chimney with a water heater, taking the furnace off that flue can leave the water heater's draft too weak, which is a safety issue and sometimes an extra cost. Ask about it specifically.

On the cooling side, 14.3 to 15.2 SEER2 is about 6% less power for the same cooling, which is a smaller effect than people expect. The upgrade that reliably changes comfort is a two-stage or variable-speed system rather than a higher rating — longer, gentler cycles and much better humidity control.

Sizing: do not replace like for like

The most common mistake in a changeout is matching the old system's tonnage because it was there.

Houses get better. New windows, attic insulation and air sealing all reduce the load, and an oversized system short-cycles — it reaches temperature quickly, shuts off, and never runs long enough to dehumidify. The symptom is a house that is cold and clammy in July.

With both machines being replaced, this is the moment to insist on a Manual J load calculation — a room-by-room heat loss and gain figure rather than a rule of thumb. It costs a few hundred dollars of somebody's time and it is the difference between a system that fits the house and a system that fits the last one.

What you are paying for

An 1,800 square foot house, 3 tons and 72,000 BTU, standard efficiency, existing ducts, furnace in a basement, at $8,750:
Condenser and coil $3,188
Gas furnace $970
Venting, gas connection, thermostat, filter rack $280
Refrigerant line set, 25 ft $259
Labor, about 20 hours around $1,182
Permit, disposal, pad and fittings $600
Overhead and margin the balance

Twenty man-hours is a day and a half for two technicians. Sixteen of those hours are fixed — the removals, the plenum transitions, the gas connection, the flue, the electrical, the vacuum and the commissioning — which is why a four-ton system costs only $1,225 more than a three-ton one.

Getting quotes

Three things to insist on, and they filter out most of the bad quotes by themselves:

  1. A written load calculation, not a tonnage matched to the old unit.
  2. Model numbers for every piece — condenser, coil and furnace — plus the AHRI certificate number for the matched combination. That certificate is what proves the system actually achieves its rated efficiency as paired.
  3. The permit included in the price, and the inspection booked. A changeout without a permit is common and is the installer's convenience rather than yours.

Then compare on what is in the quote rather than the total. Two numbers $2,000 apart are usually not the same job: one includes a new line set, a surge protector, duct sealing and a 10-year labor warranty, and the other does not.

Questions worth asking

Common questions

How much does it cost to replace a whole HVAC system?

About $8,750 for an 1,800 square foot house at code-minimum efficiency on existing ductwork — a 3-ton condenser with its coil and a 72,000 BTU 80% AFUE furnace. High efficiency on both sides is $11,125. A furnace in an attic or crawl space takes it to $10,925, and all new ductwork to $16,625.

Is it cheaper to replace the furnace and AC together?

Yes, by about $500 on a typical house — $8,750 together against $9,250 as two separate jobs. That comes from one permit, one disposal run, one trip, the plenum opened once and one commissioning visit. The better arguments for bundling are not on the invoice: the ducts are accessible with both machines out, and access to an attic or crawl space is paid for once instead of twice.

Should I replace both units if only one has failed?

Not automatically. A $500 bundling saving does not justify throwing away a unit with ten good years in it. Replace just the air conditioner and its coil if the furnace is under about 12 years old with a sound heat exchanger. Replace both if they are both past 12 years, if the heat exchanger is cracked, if the blower cannot handle the new system's airflow, or if you are moving to a 96% furnace, which changes the venting anyway.

Why does the indoor coil have to be replaced with the condenser?

Because they are one system. A new condenser on an old coil will not reach its rated efficiency or capacity, and most manufacturers will not warrant the pairing. Since the coil sits in the furnace's plenum, replacing it means opening the furnace up — which is how an air conditioning decision turns into a conversation about the furnace. Ask for the AHRI certificate number for the matched combination, which is the proof that the pair performs as rated.

What refrigerant do new air conditioners use in 2026?

R-454B or R-32. Equipment manufactured from 2025 uses these lower-global-warming refrigerants under the EPA phase-down, replacing R-410A, and they are not interchangeable — a 2026 condenser cannot be paired with an R-410A coil. The practical effect is that replacing a failed condenser in an R-410A system now means the coil as well, and often the line set, which makes a failure in an older house a bigger job than it was five years ago.

Can an R-22 air conditioner still be repaired?

Effectively no. R-22 has not been produced or imported since 2020, so repairs depend on reclaimed stock priced accordingly — a significant leak repair and recharge on an R-22 system is usually money spent on a machine that is already fifteen years old. Anything from before about 2010 is likely R-22, and finding out is the moment to price a replacement rather than a repair.

How long do a furnace and air conditioner last?

An air conditioner or heat pump 12 to 15 years, a gas furnace 15 to 20 and often more. That asymmetry is why houses commonly need a new condenser while the furnace is still sound, and it is the main case for replacing one rather than both. What shortens either is poor installation — an incorrect refrigerant charge, an airflow problem nobody measured, or oversizing that short-cycles the equipment.

Is a 96% efficient furnace worth it?

In a long cold heating season, usually; in the South, usually not. The step from 80% to 96% saves about a sixth of the gas — roughly $150 a year on a $900 heating bill — against about $2,375 more for high efficiency on both sides. A condensing furnace also vents in PVC through a wall rather than the existing flue and needs a condensate drain, which is three extra hours of work. One trap: if the old furnace shares a masonry chimney with the water heater, taking it off that flue can leave the water heater's draft too weak.

Does a higher SEER2 rating make much difference?

Less than people expect. Going from 14.3 to 15.2 SEER2 is about 6% less power for the same cooling, which on a typical cooling bill is modest. The upgrade that reliably changes how a house feels is a two-stage or variable-speed system rather than a higher rating — it runs longer, gentler cycles and controls humidity far better, which is what people actually mean when they say a house is uncomfortable at the right temperature.

What size HVAC system do I need?

Not necessarily the size you have. Houses get better — new windows, attic insulation and air sealing all cut the load — and an oversized system short-cycles, never running long enough to dehumidify, which is why some houses feel cold and clammy in summer. With both machines being replaced, insist on a Manual J load calculation: a room-by-room heat loss and gain figure rather than a rule of thumb, and the difference between a system that fits the house and one that fits the last system.

Should duct sealing be done at the same time?

If it is ever going to be done, yes. With both machines out and the plenum open, the ductwork is more accessible than it will ever be again, and sealing it then costs a fraction of what it costs as a separate job later. Ducts that leak a third of what they carry will make new equipment behave like old equipment, so it is also the cheapest way to protect the money being spent on the system.

How do I compare HVAC quotes?

Insist on three things and most bad quotes filter themselves out: a written load calculation rather than a tonnage copied from the old unit; model numbers for the condenser, the coil and the furnace plus the AHRI certificate number for the matched set; and the permit included with the inspection booked. Then compare what is in the quotes rather than the totals — two numbers $2,000 apart are usually not the same job, and the difference is a line set, a surge protector, duct sealing or a labor warranty.

Where these numbers come from

Nothing here is copied from a contractor directory. Labor is priced from what the trades are actually paid, materials from published producer prices, and both are adjusted to your area using federal cost-of-living data.