How much does it cost to replace an HVAC system?

HomeGuide publishes $5,000 to $8,300 installed for a standard-efficiency air conditioner in a 2,000 square foot home, and a tonnage table running from $4,700 for 1.5 tons to $9,500 for 5 tons. Angi puts the national average at $5,977 with a range of $1,400 to $12,500. Neither figure includes ductwork.

What is the $5,000 rule for HVAC?

Multiply the equipment's age in years by the repair quote in dollars. If the result tops $5,000, the rule says replace rather than repair. A 10-year-old system with a $300 repair comes to $3,000, so you fix it. The same system with a $600 repair comes to $6,000, so you start pricing a replacement.

Is it worth replacing just the compressor?

HomeGuide says that if the unit is still under warranty, most HVAC technicians recommend replacing just the compressor, and lists four reasons to replace the whole unit instead: the compressor is out of warranty, the unit is more than 10 years old, it has a history of other problems, or the repair costs 50% or more of a new AC.

What size air conditioner do I need?

HomeGuide's rule of thumb is 16 to 30 BTU per square foot, and one ton equals 12,000 BTU. That spread is nearly a factor of two, which is why the rule of thumb cannot size a system. The Air Conditioning Contractors of America publishes Manual J, the ANSI-approved residential load calculation, and that is what actually sizes one.

Does this calculator give me a quote?

No. It gives you two published ranges, the arithmetic on two published rules of thumb, and the numbers you typed in. Only a licensed HVAC contractor who has looked at your equipment can quote your job, and you should get three of those in writing.

Why do the cost guides disagree with each other?

Because they collect their prices differently. On a compressor replacement HomeGuide publishes $1,800 to $2,800 while This Old House and Angi both publish $800 to $2,300. On ductwork they disagree on the price per linear foot and on how many feet a house has. We print both rather than averaging them into a number nobody stands behind.

HVAC replacement cost calculator

A repair is worth doing when it costs less than half the price of a new system and the equipment still has years left. Past either line the money goes into a replacement, and this calculator prices both sides and shows the arithmetic.

This page is general information, not professional advice. It cannot see your equipment, your refrigerant or your climate, and the only number that counts is a written quote from a licensed HVAC contractor who has stood in front of your system.

1. What is being priced?

Pick the part the technician named on the quote. Each one is priced from a published cost guide, and the guide is linked next to the number.

Compressor (priced by system size)The pump in the outdoor unit. HomeGuide calls it the heart of the system — when it stops, the cooling stops.Capacitor (one published range, whatever the size)A small cylinder in the outdoor unit that gives the motors the jolt they need to start. The cheapest thing on this list by a wide margin.Blower motor (indoor) (one published range, whatever the size)The motor in the furnace or air handler that pushes air through the ducts. HomeGuide says a combined heating and cooling system may use the same blower motor for both.Condenser fan motor (outdoor) (one published range, whatever the size)A different motor from the blower. This one sits in the outdoor unit and blows heat off the condenser coil.Evaporator coil (priced by system size)The indoor coil that pulls heat and moisture out of the air. Its price swings on the warranty more than on anything else.Ductwork (one published range, whatever the size)The sheet metal and flex running through the attic, crawl space or basement. Priced by the house, never by the tonnage.The whole air conditioner (priced by system size)A full replacement — outdoor condenser and indoor coil together. There is no repair figure here, because this is the repair's alternative.

2. How big is the system?

In tons. It is printed on the data plate on the side of the outdoor unit, and it is usually in the model number as well — a 036 means 36,000 BTU, which is 3 tons.

Do not know the tonnage? Enter the square footage

3. How old is the equipment?

Years. Look for the manufacture date on the data plate, usually inside the serial number. The $5,000 rule cannot run without it.

Age in years

4. What is the repair quote?

The written number the technician gave you, parts and labor together. Leave it blank and the panel uses the top of the published range instead, and says so.

Quoted repair, in dollars

5. Is the part under warranty?

HomeGuide says most compressors carry a manufacturer warranty of 5 to 12 years, and that most warranties cover the part but not the labor. It is the single call worth making before you decide anything.

Compressor, 3 tons

Repair, published range

$2,000 – $2,600

Source: HomeGuide. This one is published per system size, so the tonnage above moved it.

A new air conditioner, installed

$5,800 – $7,800

Source: HomeGuide, its published table by tonnage. Ducts are not in that figure.

Repair or replace?

Fix it.

The published rules of thumb point at fixing it. 1 of the 1 that could run said repair.

The $5,000 rule — did not run
Needs two things this calculator will not guess: how old the equipment is, and the written repair quote. Fill both in and the rule runs.
Half the price of a new one — says repair
$2,600 at the top of the published range against $5,800 for a new 3 tons system installed is 45% of it. HomeGuide's own replace-it list includes a repair costing 50% or more of a new unit.
How old the equipment is — did not run
Look for the manufacture date on the data plate on the side of the outdoor unit, usually inside the serial number.
Whether the part is under warranty — did not run
Worth a phone call before you decide anything. HomeGuide says most compressors carry a manufacturer warranty of 5 to 12 years, and most warranties cover the part but not the labor.

Every choice above is in the web address, so the link opens on the same numbers.

The published sources do not agree on this part, and the gap is too wide to average away. HomeGuide puts a compressor replacement at $1,800 to $2,800 with a national average of $2,300. This Old House puts it at $800 to $2,300, average $1,550, and Angi at the same $800 to $2,300 with most people paying $1,200. The panel uses HomeGuide because it is the only one publishing a per-ton table. Take the other two as the reason to keep shopping the quote.

HomeGuide’s published cost to replace an air conditioner by home size. The tonnage column is its own, and it is a starting point rather than a load calculation.
Home size	Tons	Installed cost
1,000 sq ft	1.5 – 2	$4,500 – $7,000
1,200 sq ft	2 – 2.5	$5,000 – $7,500
1,500 sq ft	2.5 – 3	$6,000 – $8,500
1,600 sq ft	3 – 3.5	$6,200 – $9,000
1,800 sq ft	3 – 4	$6,500 – $10,000
2,000 sq ft	3.5 – 4.5	$7,000 – $11,500
2,200 sq ft	4 – 5	$7,800 – $12,500
2,500 sq ft	4.5 – 5	$8,500 – $13,500
3,000 sq ft	5+	$10,000 – $16,000

Source: HomeGuide.

Figures last read from their sources on August 19, 2026.

The two rules this tool runs, and where each one breaks

The first is the $5,000 rule: multiply the equipment’s age in years by the repair quote in dollars, and replace if the result tops $5,000. A 10-year-old system with a $300 repair comes to $3,000, so you fix it. The same system with a $600 repair comes to $6,000, so you start pricing a replacement. It is quick, it is memorable, and it is blind to the warranty.

The second is HomeGuide’s own line: replace when repairs will cost at least 50% of the cost of a new AC. That one is blind to age. A $2,600 compressor on a three-year-old system clears the 50% bar and is still usually the right repair, because you would be throwing away twelve good years of equipment to avoid it.

Which is why the calculator runs both and reports them separately instead of blending them into one score. When they point the same way, that is a real signal. When they split, the panel says they split and shows you each one’s arithmetic, because the disagreement is the useful part.

Where every price on this page comes from

HomeGuide for compressors, HomeGuide for capacitors, HomeGuide for blower motors, HomeGuide for evaporator coils, HomeGuide for ducts, and HomeGuide for whole systems, tonnage tables and the home-size table. Angi and This Old House are the second and third readings on the parts where one exists. Each was read first-hand on the date stamped above, and each is linked next to the figure it produced.

They do not all agree, and that is printed rather than smoothed over. On a compressor replacement HomeGuide publishes $1,800 to $2,800 while This Old House and Angi both publish $800 to $2,300— not a rounding difference, a different answer. On ductwork the two sources disagree on the price per linear foot and on how many feet a house has, which is how one of them arrives at a national average of $3,500 and the other at $1,251. Averaging those would invent a number no one published.

Sizing: what the tonnage control is really doing

The tonnage is on the data plate on the side of the outdoor unit, and it is usually in the model number too — a 036 is 36,000 BTU, and HomeGuide gives the conversion: one ton of cooling equals 12,000BTU. If you do not know it, the calculator will take a square footage instead and read HomeGuide’s published home-size table.

That table is a starting point and the page will not pretend otherwise. HomeGuide’s own rule of thumb is 16 to 30 BTU per square foot, and the two ends of that are nearly a factor of two apart. What actually sizes a system is a load calculation: Air Conditioning Contractors of America publishes Manual J, the ANSI-approved residential load calculation, alongside Manual S for equipment selection and Manual D for duct design. If a contractor quotes you a tonnage without doing one, that is the question to ask.

The ducts are the part nobody prices

Every installed figure on this page excludes them, and ENERGY STAR is blunt about what that costs a homeowner: about 20 to 30 percent of the air moving through a typical duct system is lost to leaks, holes and poorly connected ducts. A new condenser pushing conditioned air into an attic is an expensive way to heat an attic.

HomeGuide prices minor duct sealing and repairs at $300 to $1,500 and a full ductwork replacement at $1,400 to $5,600. Ask any contractor quoting a system swap whether they tested the ducts, and what the answer was.

What to ask before you sign anything

Three written quotes on the same tonnage and the same efficiency rating, so the numbers are actually comparable. Whether the part is under warranty, because HomeGuidesays compressors typically carry a manufacturer warranty of 5 to 12 years and most warranties cover the part but not the labor. What the diagnostic fee is and whether it comes off the repair. And whether the quote includes the permit — HomeGuide prices those at $100 to $250 for a straight replacement and $250 to $1,500 when ducts are involved.

On age, the honest framing is that 10 years is where the published guidance starts pointing at replacement, not where equipment stops working. HomeGuide says a new system lasts 15 to 20 years. A 12-year-old air conditioner with a cheap fault is still worth fixing; a 12-year-old air conditioner on its third repair is telling you something.

Pricing one specific part? We have the published ranges broken out on their own pages: AC compressor replacement, AC capacitor replacement, furnace and HVAC blower motors, evaporator coils and ductwork.

Questions people ask about this

How much does it cost to replace an HVAC system?: HomeGuide publishes $5,000 to $8,300 installed for a standard-efficiency air conditioner in a 2,000 square foot home, and a tonnage table running from $4,700 for 1.5 tons to $9,500 for 5 tons. Angi puts the national average at $5,977 with a range of $1,400 to $12,500. Neither figure includes ductwork.
What is the $5,000 rule for HVAC?: Multiply the equipment's age in years by the repair quote in dollars. If the result tops $5,000, the rule says replace rather than repair. A 10-year-old system with a $300 repair comes to $3,000, so you fix it. The same system with a $600 repair comes to $6,000, so you start pricing a replacement.
Is it worth replacing just the compressor?: HomeGuide says that if the unit is still under warranty, most HVAC technicians recommend replacing just the compressor, and lists four reasons to replace the whole unit instead: the compressor is out of warranty, the unit is more than 10 years old, it has a history of other problems, or the repair costs 50% or more of a new AC.
What size air conditioner do I need?: HomeGuide's rule of thumb is 16 to 30 BTU per square foot, and one ton equals 12,000 BTU. That spread is nearly a factor of two, which is why the rule of thumb cannot size a system. The Air Conditioning Contractors of America publishes Manual J, the ANSI-approved residential load calculation, and that is what actually sizes one.
Does this calculator give me a quote?: No. It gives you two published ranges, the arithmetic on two published rules of thumb, and the numbers you typed in. Only a licensed HVAC contractor who has looked at your equipment can quote your job, and you should get three of those in writing.
Why do the cost guides disagree with each other?: Because they collect their prices differently. On a compressor replacement HomeGuide publishes $1,800 to $2,800 while This Old House and Angi both publish $800 to $2,300. On ductwork they disagree on the price per linear foot and on how many feet a house has. We print both rather than averaging them into a number nobody stands behind.

When you are ready to get those three quotes, these are the HVAC companies AI assistants actually name when homeowners ask. Nobody can pay to be on these lists.