HVAC replacement cost calculator

Pick what is being replaced, the size in tons, the furnace fuel and the efficiency. Add ductwork, a thermostat and the permit, and see the low, typical and high installed price for your state with the math behind every line.

$5,888Typical 3 ton central AC, installed

$7,700Typical 3 ton heat pump, installed

By ZIPLabor scaled to your state

Central AC replacement cost

$3,700 to $8,425

Typical $6,063 (US average)

$3,700Low

$8,425High

3 tonsSize

This is a price range, not a sizing. The right size comes from a Manual J load calculation on the house, not from the old unit's label.

Free. Your numbers become an estimate you can send from your phone.

How we got this

Central AC, installed3 tons: $3,650 to $8,125 (typical $5,888)Fixr's installed price by tons and HomeAdvisor's unit price by tons plus its $300 to $1,600 installation labor, averaged. Assumes the old ducts and line set are reused.
Permit and inspection$50 to $300 a job (typical $175)Fixr and HomeAdvisor both give $50 to $300. Most towns require one for equipment changes.
RegionUS average prices (no ZIP entered)Enter a ZIP to scale the labor part of the price to your state's wages.
Total$3,700 to $8,425, typical $6,063

Item	Qty	Low	Typical	High
Central AC, 3 tons (36,000 BTU)	1	$3,650	$5,888	$8,125
Mechanical permit and inspection	1	$50	$175	$300
Total		$3,700	$6,063	$8,425

Sources: Fixr, central air conditioner installation cost; Fixr, furnace replacement cost; Fixr, heat pump installation cost; HomeAdvisor, cost to install an AC unit; HomeAdvisor, furnace replacement cost; HomeAdvisor, heat pump cost; Today's Homeowner, furnace replacement cost; Today's Homeowner, AC installation cost; Today's Homeowner, HVAC installation cost; This Old House, HVAC replacement cost; This Old House, HVAC installation cost; This Old House, air conditioner costs; BLS Occupational Employment and Wage Statistics, May 2025 (state and national files); US Census Bureau, 2020 ZIP Code Tabulation Area to county relationship file. Checked 2026-10-08.

Add this calculator to your websiteFree. Paste the code into any page builder that takes HTML. It fits its own height and works on phones.

<iframe src="https://www.koira.ai/embed/tools/hvac-replacement-cost-calculator" title="HVAC replacement cost calculator" width="100%" height="900" style="width:100%;max-width:100%;height:900px;border:0;display:block" loading="lazy" allow="clipboard-write" data-koira-tool="hvac-replacement-cost-calculator"></iframe>
<p style="margin:6px 0 0;font-size:13px"><a href="https://www.koira.ai/tools/hvac-replacement-cost-calculator" rel="noopener">Free calculator by Koira</a></p>
<script>(function(){if(window.__koiraTools)return;window.__koiraTools=1;var ok=["https://www.koira.ai","https://koira.ai"];addEventListener("message",function(e){var d=e.data;if(!d||d.type!=="koira:tool-height"||ok.indexOf(e.origin)<0)return;var f=document.querySelectorAll("iframe[data-koira-tool]");for(var i=0;i<f.length;i++)if(f[i].contentWindow===e.source)f[i].style.height=Math.max(200,Math.min(8000,Math.ceil(+d.height||0)))+"px";});})();</script>

Key takeaways

A 3 ton central AC typically costs $3,650 to $8,125 installed, $5,888 typical, reusing the old ducts.
A gas furnace runs $3,800 to $10,000 installed and an electric furnace $2,000 to $7,000.
A 3 ton air-source heat pump runs $5,300 to $10,100, and it replaces both the AC and the furnace.
New ductwork adds $1,000 to $6,000. Higher efficiency adds about $1,000 to $6,000 more for the equipment.

How much does a new central AC cost by tons

Central air is sized in tons. One ton is 12,000 BTU an hour of cooling. Most houses take 2 to 5 tons. We combined two published tables for every size: Fixr's installed price by tons, and HomeAdvisor's unit price by tons plus its $300 to $1,600 for installation labor. The low is the average of the two lows, the high the average of the highs, and the typical price the average of the two midpoints.

Size	Low	Typical	High
1.5 tons (18,000 BTU)	$2,625	$4,275	$5,925
2 tons (24,000 BTU)	$3,025	$5,038	$7,050
2.5 tons (30,000 BTU)	$3,275	$5,350	$7,425
3 tons (36,000 BTU)	$3,650	$5,888	$8,125
3.5 tons (42,000 BTU)	$4,025	$6,300	$8,575
4 tons (48,000 BTU)	$4,925	$7,313	$9,700
5 tons (60,000 BTU)	$5,450	$8,325	$11,200

HomeAdvisor has no 2.5 or 3.5 ton row, so for those sizes we use the halfway point of its rows either side. These prices assume a change-out: the old ducts, line set and pad are reused. Today's Homeowner puts a standalone central AC at $5,000 to $14,000, and Fixr's $5,800 to $14,400 national range includes new ductwork, which is why both run higher than a plain swap.

Which size do you need?The size on the old unit's label is a starting point, not an answer. Houses change: new windows, insulation and additions all change the load. Fixr's table puts a 1,000 sq ft home at about 2 tons and a 2,000 sq ft home at 3 to 4. A proper Manual J load calculation is how a contractor should size it. Our HVAC load calculator gives a first estimate.

Furnace and heat pump replacement cost

Furnaces are sold by fuel and by BTU. Three guides give installed ranges by fuel; we take the middle of their lows, the middle of their highs and the middle of their midpoints.

Furnace	Low	Typical	High
Natural gas	$3,800	$6,900	$10,000
Electric	$2,000	$4,500	$7,000
Oil	$6,700	$8,350	$10,000

Those ranges cover every size of furnace. A small house with a 60,000 BTU unit sits near the bottom, and a big house that needs 120,000 BTU or more sits near the top. Fixr, HomeAdvisor and Today's Homeowner all put the average furnace replacement near $4,800, which mixes cheaper electric units in with gas.

A heat pump heats and cools, so it replaces both the AC and the furnace. We combined HomeAdvisor's price by tons with Fixr's price by home size and recommended tonnage:

Air-source heat pump	Low	Typical	High
2 tons	$4,250	$5,500	$6,750
2.5 tons	$5,200	$7,550	$9,900
3 tons	$5,300	$7,700	$10,100
3.5 tons	$5,950	$9,575	$13,200
4 tons	$6,000	$9,825	$13,650
5 tons	$7,000	$11,200	$15,400

Fixr's figures include hooking the heat pump into a central system, so they run higher than HomeAdvisor's, and averaging the two gives a wide band. This Old House's survey of 1,000 homeowners found an average of $8,007 for an air-source heat pump replacement, which sits inside the 3 ton band.

What changes the price of a new HVAC system

Efficiency. SEER2 is the cooling efficiency rating. The federal minimum depends on where you live: Fixr's table lists SEER 14 (13.4 SEER2) for the North and SEER 15 (14.3 SEER2) for the South and Southwest. Going from SEER 14 to SEER 16 adds $1,150 to $2,400 to an AC in Fixr's equipment prices; going to SEER 20 adds $4,025 to $6,000. For heat pumps, HomeAdvisor's prices put the same steps at $800 to $1,300 and $2,000 to $4,600. Each of those is one source, and the calculator says so.
Ductwork. Reusing good ducts is the biggest saving there is. When they are leaking, crushed, or the wrong size for the new unit, HomeAdvisor gives $1,000 to $5,000 for new ductwork, Fixr $1,400 to $6,000 and Today's Homeowner $1,000 to $6,000.
Access. An attic air handler, a tight closet or a long line set run adds hours. A rooftop unit may need a crane.
Electrical. A bigger unit or an electric furnace may need a new circuit. Fixr puts a new 240 volt circuit for an electric furnace at $175 to $500.
Permit. Fixr and HomeAdvisor both give $50 to $300. Most towns require one when equipment is replaced.
Brand. In This Old House's 2026 survey, average central AC replacement costs ran from about $6,572 for American Standard to $10,069 for Lennox.
Season. Spring and fall are slower for HVAC crews than the first heat wave or cold snap, and prices and schedules show it.

A worked example: AC and gas furnace together

A homeowner has a 20-year-old 3 ton AC and a gas furnace in a 1,800 sq ft house. Both are tired, so they want both replaced at once, standard efficiency, with the permit.

Central AC, 3 tons. $3,650 / $5,888 / $8,125.
Gas furnace. $3,800 / $6,900 / $10,000.
Permit. $50 / $175 / $300.
Total. $7,500 to $18,425, with $12,963 as the typical price at the US average.

That is the sum of the two jobs priced on their own. Today's Homeowner and This Old House both put a standard full HVAC replacement at $5,000 to $12,500, and This Old House's survey average was $8,209. Buying both at once is usually cheaper than the sum, because one crew, one trip and one permit cover both. Ask for a package price and compare it with the calculator's sum.

Labor is about a quarter to a third of an HVAC replacement; Fixr puts the labor on a 3 ton change-out at $1,250 to $3,000. The calculator treats 30% as labor and scales that part to your state's construction wages when you enter a ZIP.

Repair or replace

This Old House's survey found the average HVAC repair cost $775, against $8,209 for a replacement. Its rule of thumb: multiply the repair price by the age of the system in years. If the result is over $5,000, replacing usually makes more sense. A $600 repair on a 12-year-old AC comes to $7,200, so replace. The same repair on a 5-year-old unit comes to $3,000, so repair.

Other signs that point to replacement:

The system uses R-22 refrigerant, which is no longer made, so refrigerant repairs are expensive.
Repairs are coming every season.
Some rooms are always too hot or too cold, which can mean the system was sized wrong in the first place.
Energy bills keep climbing for the same weather, which often means a tired compressor or a furnace that has lost efficiency.
The furnace has a cracked heat exchanger. That is a safety issue, because it can leak carbon monoxide into the house.

SafetyThis calculator gives a price range, not a sizing or a design. The right size comes from a Manual J load calculation on the house, and gas, refrigerant and electrical work need a licensed HVAC contractor and, in most places, a permit. Every house with a fuel-burning furnace should have working carbon monoxide alarms.

How to compare HVAC quotes

Get three quotes and make them comparable:

Same size, same efficiency. A quote for a 3 ton SEER 14 unit and one for a 3.5 ton SEER 16 unit are not the same job. Ask each contractor how they sized it. A contractor who measures the house and runs a load calculation is a good sign.
Model numbers. Ask for the outdoor unit, the indoor coil or air handler, and the furnace by model number, so you can check that the AC and coil are a matched pair.
What is included. Line set, pad, disconnect, thermostat, haul-away of the old unit, permit and startup.
Ductwork. Whether the ducts are being reused, sealed or replaced, and why.
Warranty. Parts and labor, how long, and whether the equipment needs registering.
Rebates. Ask about utility and state rebates for high-efficiency equipment, and check the current federal rules yourself.

A quote well under the low end usually leaves something out. A quote well above the high end should come with a reason: new ducts, a hard install, a premium brand or a high-efficiency unit.

How HVAC contractors price a replacement

If you install HVAC equipment, the ranges above are what homeowners read before they call. Your own price should come from your own numbers:

Equipment at your cost, plus the coil, line set, pad, thermostat, refrigerant and small parts.
Crew hours at what each hour really costs you, with payroll taxes and insurance. Our HVAC labor rate calculator works that out.
Permit, crane or lift, disposal as their own lines.
Margin on top. Our profit margin calculator shows the price that hits the margin you want.
Good, better, best. Offer standard, high and premium efficiency side by side. The calculator's efficiency step shows the difference in equipment price for each tier.

The "Save as an estimate" button above carries the equipment, the efficiency upgrade, ducts and permit into a Koira estimate. You can send it from Koira, let the customer approve and pay a deposit on their phone, and offer financing on a big ticket.

Last checked October 8, 2026. More for your trade: how HVAC companies run on Koira.

FAQ

How much does it cost to replace an HVAC system?

A standard full system, AC and furnace, typically costs $5,000 to $12,500 according to Today's Homeowner and This Old House. Priced separately, a 3 ton AC runs $3,650 to $8,125 and a gas furnace $3,800 to $10,000, and a package price for both is usually below that sum.

How much does a new AC unit cost per ton?

Installed, a 2 ton central AC typically costs $3,025 to $7,050, a 3 ton $3,650 to $8,125 and a 5 ton $5,450 to $11,200, reusing the existing ducts.

How much does a new furnace cost?

A gas furnace costs $3,800 to $10,000 installed, an electric furnace $2,000 to $7,000 and an oil furnace $6,700 to $10,000. The average furnace replacement is near $4,800.

How much does a heat pump cost to install?

An air-source heat pump costs about $5,300 to $10,100 for 3 tons and $7,000 to $15,400 for 5 tons. It replaces both the AC and the furnace.

What size AC do I need?

Fixr's table puts a 1,000 sq ft home at about 2 tons and a 2,000 sq ft home at 3 to 4 tons. The right answer comes from a Manual J load calculation on the house, not the size of the old unit.

Should I replace my AC and furnace at the same time?

Often, yes, if both are near the end of their life. One crew, one trip and one permit cover both, and the indoor coil and outdoor unit are matched. Ask for a package price.

Is it worth paying for a higher SEER rating?

It depends on how much you run the AC and what power costs where you live. Going from SEER 14 to SEER 16 adds about $1,150 to $2,400 to an AC. Our SEER savings calculator shows how long the savings take to pay that back.

More free tools

Trade mathHVAC load calculatorCooling and heating load, part by part, with the tons and furnace range.Trade mathSEER savings calculatorOld AC vs new: yearly savings and payback, in SEER or SEER2.Price a jobAir duct cleaning cost calculatorDuct cleaning by square foot or vent, with extra systems and add-ons.Price a jobInsulation cost calculatorBlown-in, batts, spray foam or board, in attics and walls, with R-values.Run the businessHVAC labor rate calculatorHVAC rate per billable hour, starting from the BLS median tech wage.