When Your AC Blows Warm: Evaporator Replacement in San Antonio
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What’s Covered on This Page
- Signs Your Evaporator Coil Has Failed
- Warranty Status Changes Your Replacement Cost
- When Warm Air Doesn’t Mean a Bad Coil
- R-22 Systems and Northwest San Antonio Homes
- What Happens During a Professional Coil Replacement
- How long does evaporator coil replacement take?
- What should I expect when your technician arrives to check my coil?
- Why do evaporator coils fail so often in San Antonio homes?
- How much does evaporator coil replacement cost?
- How do I know if I really need a new evaporator coil, or is something else causing warm air?
- Do older R-22 systems in Northwest San Antonio need special handling for coil replacement?
Signs Your Evaporator Coil Has Failed
When a homeowner calls about warm air blowing from the vents, it often points to the evaporator coil. This part inside your indoor unit cools the air. When it is cracked or corroded, your system loses its ability to cool.
What does a bad coil look like on a service call? We pull the access panel and look for specific issues.
- Ice building up on the copper refrigerant lines, even in July
- A hissing or bubbling noise near the indoor unit when the system runs
- Water pooling under the air handler or dripping from vents
- A musty smell coming through the ducts, a sign of standing condensate
- Higher electric bills with no other explanation
- The system short cycling, running for a few minutes then shutting off
San Antonio attics often get very hot. Most systems sit in the attic, where summer temperatures can climb past 120 degrees. That heat stresses the coil’s metal. It speeds up the corrosion that eats tiny pinholes through the coil walls over time.
Once refrigerant escapes through those pinholes, it is gone. Topping it off is only a temporary patch.
A homeowner called us last summer after noticing a wet spot on the ceiling below the attic unit. This was condensate backing up because the coil had frozen solid overnight. It melted the next day and overflowed the drain pan.
Warranty Status Changes Your Replacement Cost
Most homeowners do not know this until we are in their attic. The biggest factor in AC evaporator coil replacement cost is not the brand of your system or how big your house is. It is whether that coil is still covered under the manufacturer’s factory warranty.
If your evaporator coil is still under warranty, the part itself is free from the manufacturer. You pay for labor, an acid flush, a new filter drier, new refrigerant, balancing the system, and the paperwork to process that warranty claim. That job runs $1,250. It is straightforward.
If the warranty has lapsed, you are buying the coil outright. You pay for the same labor, acid flush, filter drier, refrigerant, and system balancing. Now the coil itself is on the invoice. That version runs $3,220, and it is the most common job we see.
- New evaporator coil (warranty covered or purchased, depending on status)
- Acid flush to clear contamination from the line set
- New filter drier
- New refrigerant charge
- Labor to remove the old coil and install the new one
- System balancing and a full operational test
- Warranty processing paperwork, when it applies
We check warranty status before we quote you a number. Many people assume their coil is out of warranty just because the system is a few years old. Most coils carry longer coverage than people expect. Do not guess. Do not let anyone quote you a price without pulling that serial number first.
We offer a free estimate for this reason. We will check the warranty, look at the coil, and tell you which scenario you are in before you spend a dime.
When Warm Air Doesn’t Mean a Bad Coil
Warm air blowing out of your vents feels like an emergency. It is not always the coil. We get calls almost every week from homeowners sure their evaporator coil is shot. About half the time it is something else.
A dirty air filter chokes airflow across the coil. That alone can make air feel warm even when the coil is fine. San Antonio homes pull in a lot of fine dust from the caliche soil. Filters here clog faster than you expect. A weak capacitor or a failing blower motor can also starve the system of airflow. Low refrigerant from a leak elsewhere in the line set will mimic coil failure. The coil cannot do its job without the right charge running through it.
How do you tell the difference? You usually cannot, not from the living room.
- Ice forming on the copper refrigerant lines outside, often a sign of low airflow or low charge rather than coil failure
- Water pooling near the indoor unit, which points to a clogged condensate line before it points to the coil
- A musty smell from the vents, usually mold in the drain pan or duct, not the coil itself
- Warm air only during peak afternoon heat, which can mean an undersized or overworked system rather than a bad coil
A technician has to check refrigerant pressures, inspect for oil residue at the coil fins, and run the system under load before condemning the coil. Skip that step and you might pay for a coil you did not need. We offer a free estimate. You get an actual diagnosis instead of a guess based on symptoms alone.
Have questions? We’re happy to help.
Get a Free Estimate. Atlas AC Repair is ready to help.
R-22 Systems and Northwest San Antonio Homes
Many homes in Northwest San Antonio went up in the 1980s and 90s. Plenty of those original AC systems still run on R-22 refrigerant. R-22 got phased out of production years back. It is harder to find now, and it costs more than newer refrigerant blends.
Here is what that means for you. If your evaporator coil fails on an old R-22 system, we cannot swap it under a factory warranty. The coil is old. The manufacturer coverage ran out long ago. The job runs as a full replacement job with new refrigerant included.
We see this often on service calls in older parts of San Antonio. The system works fine for years. Then a slow leak in the coil catches up with it during a hot stretch.
- Ice forming on the copper lines even when the unit is running
- A hissing or bubbling sound near the indoor unit
- Higher indoor humidity than usual, even with the AC on
- Rooms that used to cool fine now staying warm
If your home still has one of these older systems, do not wait for a full breakdown in July. We will look at the coil, check the refrigerant type, and give you a free estimate before anything gets torn apart.
What Happens During a Professional Coil Replacement
Most San Antonio air handlers sit in a closet, garage, or attic. That attic space can hit well over 120 degrees by July. We work fast up there for a reason. Here is the order things usually go once we confirm the coil is the problem.
- We recover the existing refrigerant safely. Then we pull the old coil out of the cabinet.
- The line set and cabinet get an acid flush. This clears out any acid or debris left behind from the failed coil. It keeps it from contaminating the new one.
- We install a new filter drier every time. Skipping this step is a mistake we see other shops make. It shortens the life of the new coil.
- The new evaporator coil goes in and gets sealed to the cabinet and duct connections.
- We pull a vacuum on the system to remove moisture and air from the lines.
- New refrigerant gets weighed to the manufacturer’s spec. We do not just top it off by feel.
- We balance the system, run it, and check temperatures at the vents and the coil itself.
Once the coil is replaced and the system is balanced, the airflow problem the homeowner called about disappears. We test the system running for a while before we call it done. We clean up the work area. We walk the homeowner through what we found and what we did. If the coil is still under manufacturer warranty, we handle the warranty paperwork ourselves so the homeowner does not have to chase it down.
Frequently Asked Questions
Common questions about Evaporator replacement
How long does evaporator coil replacement take?
Most evaporator coil replacements take one full day, sometimes less. We remove the old coil, run an acid flush to clear the line set, install the new coil, add fresh refrigerant, and balance the system before we leave. If your coil is still under manufacturer warranty, the paperwork can add a little time upfront. Once the new coil is in, we test the system under load to make sure it cools properly before we call the job done.
What should I expect when your technician arrives to check my coil?
Your technician will pull the access panel on your indoor unit and inspect the coil directly. You should expect us to check for ice on the copper lines, listen for hissing near the unit, and look for water pooling under the air handler. We also check refrigerant pressure and pull the coil’s serial number to confirm warranty status. You get a clear answer about what is wrong before any work starts, not just a guess based on warm air alone.
Why do evaporator coils fail so often in San Antonio homes?
San Antonio attics get brutally hot, and that heat speeds up coil corrosion faster than in cooler climates. Most indoor units sit in attics where summer temperatures climb past 120 degrees. That heat stresses the coil’s metal and creates tiny pinholes over time, which let refrigerant leak out. Once refrigerant escapes through those pinholes, topping it off only buys you a little time. This is why coil failures show up sooner here than in many other parts of the country.
How much does evaporator coil replacement cost?
The cost depends mainly on whether your coil is still covered under the manufacturer’s factory warranty. If it is, you pay for labor, an acid flush, filter drier, refrigerant, and system balancing, but the coil part itself is free. If the warranty has lapsed, you also pay for the coil on top of that same labor and materials. We check your serial number and warranty status first, so you know which scenario applies before we quote any work.
How do I know if I really need a new evaporator coil, or is something else causing warm air?
Warm air does not always mean a bad coil. About half the calls we get turn out to be a dirty air filter, a weak capacitor, or low refrigerant from a leak elsewhere in the line set. San Antonio’s dusty caliche soil clogs filters faster than most homeowners expect, which chokes airflow across the coil. A technician needs to check refrigerant pressure and inspect the coil fins under load before deciding the coil itself has failed.
Do older R-22 systems in Northwest San Antonio need special handling for coil replacement?
Yes, R-22 systems usually need a full replacement job rather than a warranty repair. Many homes in Northwest San Antonio were built in the 1980s and 90s and still run original R-22 systems. R-22 is no longer manufactured, so it costs more and manufacturer coverage on these old coils has typically run out. When the coil fails on one of these systems, the job includes new refrigerant along with the coil, since a warranty claim usually is not an option.
