How much does evaporator coil replacement cost?
Expect $650 to $2,000 installed, and around $1,200 for a common 2.5 to 3 ton residential system with reasonable access. The split is roughly $180 to $1,500 for the coil and $400 to $900 for labor, plus the refrigerant that has to be weighed back in. Most shops also charge a $75 to $200 diagnostic fee, which the good ones credit toward the repair once you approve the work.
Larger systems cost more because the coil is physically bigger and holds more refrigerant, not because the labor changes much. A small coil for a 1.5 to 2 ton system tends to land at the bottom of the range, while a 4 to 5 ton coil pushes toward $1,800 to $2,500. A condenser coil in the outdoor unit is a different and pricier job at $900 to $2,800, so make sure the quote says which coil actually failed.
The job itself is usually a half day. A tech recovers the existing refrigerant, cuts and unbrazes the line set connections, pulls the old coil out of the air handler or furnace plenum, sets and brazes in the new one, pulls a vacuum to remove moisture, then weighs in the factory charge. That vacuum step is the one homeowners never see and the one that separates a coil that lasts a decade from one that fails again in two years.
What makes one coil replacement cost more than another?
Four things move the price the most: coil size, whether it is cased or uncased, how hard the air handler is to reach, and which refrigerant your system uses. A cased coil (the coil pre-mounted in a sheet metal box) costs $200 to $600 more than an uncased slab but installs faster and seals better, so on many jobs the total lands close either way.
Access is the quiet budget killer. A coil sitting on a furnace in an open basement is straightforward work. The same coil in a low attic in August, or in a closet where the plenum has to be cut apart and rebuilt, can add $200 to $500 in labor. Get the tech to tell you which situation you have before you compare quotes, because two bids on the same house can differ purely on how much sheet metal work each one is planning.
Refrigerant type matters twice. An R-410A system needs 6 to 12 pounds weighed back in at current R-410A prices, which alone can be a few hundred dollars. An older R-22 system is worse, because R-22 now runs $100 to $200 per pound and the replacement coil is getting scarce. The new coil also has to be an AHRI-matched pair with your outdoor unit. A mismatched coil costs less today and quietly costs you efficiency and compressor life for the rest of the system's run.
Does the warranty cover an evaporator coil replacement?
Often yes on the part, almost never on the labor. Most major brands carry a 10-year parts warranty on the evaporator coil, but nearly all of them require the system to have been registered within 60 to 90 days of installation. If the original installer registered it, you are covered. If nobody did, many brands fall back to a shorter 5-year term. Call the manufacturer with your model and serial number before you approve any quote, because this single check is worth several hundred dollars.
A covered coil still leaves you a bill of roughly $400 to $1,200 for labor, refrigerant, and the service call, since labor warranties usually expire after the first year or two. That is the number to compare against replacement, not the full $1,200 sticker. Some shops also add a modest handling charge for processing the warranty claim, which is normal but should be disclosed up front.
Watch for one common upsell. If a coil is under warranty, a contractor has less margin in the repair than in selling you a new system, so you may hear that replacement is the only sensible path. Sometimes that is true, especially on an old unit. But ask directly whether the coil is covered and what the out-of-pocket repair would be, then decide with both numbers in front of you.
How do you know if your evaporator coil is bad?
The classic sign is an AC that runs constantly but blows air that is barely cool, because a leaking coil has lost the refrigerant charge it needs to absorb heat. You may also see ice on the coil or the copper line running to the outdoor unit, hear a faint hissing or bubbling near the indoor air handler, or find an oily residue on or under the coil where refrigerant and compressor oil have seeped out together.
Rising electric bills with no change in habits point the same direction. A system low on charge runs far longer to hit the thermostat setpoint, so the bill climbs before the cooling failure becomes obvious. If your unit is icing over, work through why your AC is freezing up first, because a dirty filter or a failing blower causes the same symptom and costs a fraction to fix.
The honest diagnostic is a pressure test. A tech isolates the coil, pressurizes it with nitrogen, and either finds the leak with an electronic detector or watches the pressure drop. Insist on this before paying for a coil. A shop that diagnoses a bad coil purely from a low charge reading is guessing, and the leak might be in the line set or the condenser instead. For what the part actually does and where it sits, see what an evaporator coil is.
Why do evaporator coils leak in the first place?
Most coil leaks are formicary corrosion, a pinhole failure caused by formic acid attacking the copper from the outside. The acid comes from ordinary indoor sources: cleaning products, adhesives, new carpet, paint, and building materials that off-gas volatile organic compounds. The pinholes are far too small to see, which is why the failure shows up as a slow loss of cooling over a season rather than a sudden breakdown.
Timing is fairly predictable. Formicary corrosion typically surfaces between year 5 and year 15, and it was bad enough on certain mid-2000s copper coil designs that several manufacturers extended warranties over it. Coils with aluminum tubing resist this failure mode better and are now common on newer equipment, which is one genuine advantage of a modern replacement coil over the one you are pulling out.
The rest of the causes are simpler. Vibration wears through tubing where it contacts a bracket, dirt and biofilm trap moisture against the metal, and a small share of coils simply arrive with a weak braze joint. Keeping the coil clean and the filter changed does not prevent formicary corrosion, but it does prevent the airflow problems that stress the whole system. A yearly AC tune-up is where a tech would catch a slow leak before it strands you in July.
Should you replace the coil or the whole AC system?
Replace the coil if the system is under 10 years old and the coil is under warranty. Replace the whole system if it is over 12 years old, uses R-22, or is facing a second major repair. The quick test most contractors use is the $5,000 rule: multiply the age of the unit by the repair cost, and if the result tops $5,000, put the money toward replacement. A $1,200 coil on an 8-year-old system scores 9,600, which says replace, though warranty coverage can flip that math.
R-22 makes the decision easy. If your system still runs R-22, a coil replacement means paying a premium for an obsolete refrigerant on equipment that is at minimum 15 years old. That money is better spent on a new system that uses a current refrigerant and will not need this conversation again. The same logic applies when the compressor is also showing its age, since replacing a compressor is the one repair that costs even more than a coil.
If you land on replacement, get the sizing right rather than copying whatever is currently installed, since a lot of existing systems were oversized by habit. Run the numbers with the BTU calculator, then read how much a new AC costs so the quotes hold no surprises. If you are only pricing the repair, AC repair costs by part shows where a coil sits against everything else that commonly fails.
Frequently asked questions
Is it worth replacing an evaporator coil?
It is worth it if the system is under about 10 years old, especially when the coil is still under the manufacturer's 10-year parts warranty and your out-of-pocket cost is only the $400 to $1,200 in labor and refrigerant. It is usually not worth it on a system over 12 years old, on an R-22 system, or when a second major component is also failing, because you would be spending over $1,000 on equipment near the end of its 12-to-17-year lifespan.
What is the $5,000 rule for AC?
The $5,000 rule is a quick repair-or-replace test: multiply the age of the unit in years by the cost of the repair, and if the answer is more than $5,000, replace the system instead of fixing it. A $1,200 evaporator coil on a 4-year-old unit scores 4,800, so you repair it. The same coil on a 10-year-old unit scores 12,000, so you replace. Treat it as a starting point, since an active parts warranty can make the repair worth doing well past what the rule suggests.
What is the most expensive part of an AC unit to replace?
The compressor is the most expensive single part at roughly $1,200 to $2,800 out of warranty, because the part is costly and the labor is heavy. Coils come next: an evaporator coil runs $650 to $2,000 installed and a condenser coil $900 to $2,800. All three require recovering and recharging refrigerant, which is a large part of why they cost what they do. If any of them fail on a system older than 10 years, replacement usually makes more financial sense.
How do I tell if my evaporator coil is bad?
The main signs are air that is not getting cold while the unit runs nonstop, ice forming on the coil or the refrigerant line, a hissing or bubbling sound near the indoor air handler, an oily residue around the coil, and electric bills climbing with no change in use. Those symptoms all point to a refrigerant leak, but a dirty filter or a weak blower can mimic them, so have a tech pressure-test the coil with nitrogen before you agree to replace it.
How much does it cost to replace an AC coil?
An evaporator coil (the indoor one) costs $650 to $2,000 installed, averaging about $1,200. A condenser coil (the outdoor one) costs $900 to $2,800. If the part is still under a 10-year parts warranty, you pay only labor and refrigerant, roughly $400 to $1,200. Price differences come down to system size, whether the coil is cased or uncased, how accessible the air handler is, and which refrigerant your system uses.