Evaporator Coil Cleaning, Repair & Replacement — Above & Beyond Air Conditioning & Heating
Indoor coil cleaning, leak repair, full coil replacement, microchannel-safe chemistry, and attic AHU access. 30-day warranty on every repair.
The evaporator coil is the indoor half of your AC system, the cold heat-exchanger that absorbs heat from your house air, turning warm return air into cool supply air. When it freezes, leaks refrigerant, gets clogged with dust and biofilm, or corrodes through, your AC stops cooling effectively even when the compressor is running fine. Evaporator coil issues are responsible for roughly 25% of the no-cool calls we field in San Antonio.
Above & Beyond services evaporator coils on every major brand. Free $89 diagnostic credited back with repair. Written estimate with verbatim parts and labor before any work. We carry coil cleaning chemistry on every truck, plus electronic leak detectors for refrigerant work, plus replacement coils for the most common SA installations (microchannel and tube-and-fin, R-410A and R-454B/R-32 systems).
Evaporator coil replacement is one of the larger repair items on an AC system, and one where the repair-vs-replace decision often tips toward full condenser-and-coil replacement on older systems. We walk through the math during the diagnostic, side-by-side.
The Three Ways a Capacitor Fails in San Antonio
Nearly every AC will not start call traces to one of three patterns. The symptom tells us most of what we need before we open the panel.
Frozen Coil
Airflow-Restriction Failure
Refrigerant Leak
Slow-Build Failure
Biofilm and Dust Clog
Slow-Build IAQ Failure
Failure #1: Frozen Coil (the airflow-restriction failure)
When the evaporator coil's surface temperature drops below 32 degrees during operation, condensate freezes on the fins, ice builds up, and airflow stops entirely. SA homeowners call this AC blowing warm air or no cooling. The root causes are almost always upstream: dirty air filter restricting return airflow, blower motor weakening, duct restriction, or low refrigerant from a slow leak. We diagnose the root cause, thaw the coil safely (4-6 hours powered off with the blower running fan-only), then fix the underlying restriction. Skipping root cause and just thawing the coil means refreezing within days. Cost: $145-$245 for diagnostic plus filter or blower fix; $385-$685 if refrigerant leak repair is needed.
Failure #2: Refrigerant Leak in the Coil (the slow-build failure)
Aluminum microchannel coils develop micro-cracks at brazed joints after 8-12 years in SA's 130 degree-plus summer attic environments. Copper-tube aluminum-fin coils develop corrosion-through holes from formicary corrosion (caused by indoor air contaminants including cooking fumes, cleaning products, and off-gassing) after 10-15 years. Symptoms: long runtimes, weak cool air, frozen coil (refrigerant short-charge causes freeze too), and rising electric bills. We use electronic leak detectors per Tommy's protocol, no UV dye, no soap bubbles, no guesswork. Repair if leak is repairable (rare on coils), full coil replacement $1,400-$2,400 if not.
Failure #3: Biofilm and Dust Clog (the slow-build IAQ failure)
Evaporator coils run wet in cooling mode. Wet aluminum fins plus indoor dust, pet hair, and pollen creates biofilm and dirt accumulation on the coil surface. Symptoms: reduced cooling capacity, longer runtimes, mold smell from vents, elevated indoor humidity that will not drop, and asthma or allergy symptoms worsening when AC runs. Cleaning the coil restores efficiency and indoor air quality. Cost: $150-$400 depending on coil accessibility and severity. Most needed every 3-5 years for typical residential installs; every 18-24 months for pet-heavy households or near-construction homes.
Our Coil Diagnostic and Service Process
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A real San Antonio team member answers. We ask whether you are seeing reduced cooling, water issues, ice, or smells. That frames whether the call is dirty coil, leaking coil, frozen coil, or replacement decision.
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Text with the tech's name and photo. No mystery dispatch.
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Roughly 30-40 minutes on site. Visual inspection of the coil (accessible inspection only on some installations; full inspection requires panel removal). Refrigerant pressures measured with calibrated gauges. Static pressure across the coil (a fast indicator of dirty-coil restriction). Superheat and subcool readings to verify charge. Electronic leak detector traverse of all visible fittings and the coil surface itself. We diagnose the root cause before quoting any work.
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Verbatim parts and labor. For coils, the choice points are: cleaning only, leak repair and recharge, or full coil replacement. For coil replacement on older systems, we quote both coil-only and full system replacement so you can make the repair-vs-replace decision with full information.
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Coil cleaning: 60-90 minutes including chemistry dwell time.
Leak repair: 60-120 minutes depending on leak location, includes refrigerant recovery, repair, deep vacuum to 500 microns, and recharge by weight.
Coil replacement: 4-6 hours typical, often a same-day finish. We document the work on the service record.
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Final commissioning: refrigerant pressures, superheat/subcool, temperature split (return to supply), static pressure across the coil. We log the readings. 30-day callback warranty on every coil service.
Evaporator Coil Service Pricing in San Antonio
Diagnostic: $89 diagnostic fee. Credited back when you approve the repair. $89 if you decline, no pressure, no upsell.
| Service | Price Range |
|---|---|
| Coil cleaning (accessible installations, light biofilm) | $150 – $285 |
| Coil cleaning (attic installations, heavy biofilm, requires panel removal) | $245 – $400 |
| Coil fin straightening (hail or debris damage) | $145 – $285 |
| Schrader core replacement at coil service valve | $145 – $185 |
| Drain pan cleaning and tablets | $85 – $145 |
| Refrigerant leak repair and recharge R-22 (where serviceable) | $585 – $985 |
| Refrigerant leak repair and recharge R-410A | $385 – $685 |
| Refrigerant leak repair and recharge R-454B and R-32 (A2L) | $485 – $785 |
| Full system refrigerant recovery and recharge by weight | $345 – $585 |
| Universal aluminum microchannel coil, 2–3 ton | $1,400 – $1,800 |
| Universal aluminum microchannel coil, 3.5–5 ton | $1,800 – $2,400 |
| OEM coil (Carrier, Day & Night, American Standard, Trane), 2–3 ton | $1,800 – $2,400 |
| OEM coil, 3.5–5 ton | $2,200 – $2,800 |
| Full system replacement (often better economic choice on 10+ year systems) | $7,500 – $15,000 depending on tier and tonnage |
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Above & Beyond Coil Service vs. National HVAC Chains
| Feature | Above & Beyond | National HVAC Chains |
|---|---|---|
| Diagnostic Approach | Root cause first (filter, blower, ductwork), then coil work | Often jump straight to coil work or refrigerant top-off |
| Leak Detection Method | Electronic detector per Tommy's protocol, UV dye, no soap bubbles | Often UV dye injection or soap bubbles (less accurate, takes longer) |
| Coil Cleaning Chemistry | Right cleaner for coil type, non-acid for microchannel, acid-rinse for copper-fin | Often same generic cleaner regardless of coil type |
| Refrigerant Coverage | R-22, R-410A, R-454B, R-32 all stocked on every truck | Often R-410A only; A2L requires schedule |
| Diagnostic Pricing | $89 credited back when you approve the repair | $89 to $149 charged upfront, often not refundable |
| Charge By Weight | Every recharge is weighed to manufacturer spec | Often charged by gauge pressure (less accurate in SA heat) |
| Coil Replacement vs Full System | Side-by-side written estimate so you decide | Often only full system replacement quoted |
| Estimate Format | Written estimate with verbatim parts and labor | Verbal estimates, change orders common |
| Technician Compensation | Hourly and completion pay, no commission pressure | Commission-driven, techs paid percentage of what you spend |
| Warranty on Repair | 30-day callback warranty included | Often 7 to 14 days, sometimes nothing |
Frequently Asked Questions
How much does evaporator coil service cost in San Antonio?
Coil cleaning runs $150-$400, depending on coil accessibility and biofilm severity. Refrigerant leak repair plus recharge runs $385-$985 depending on refrigerant type. Coil replacement runs $1,400-$2,800, depending on tonnage and universal vs OEM choice. The $89 diagnostic is credited back when you approve the repair.
Why does my evaporator coil keep freezing?
Frozen coils have four common root causes: dirty air filter (most common), weak blower motor, ductwork restriction, or low refrigerant charge from a slow leak. We diagnose the root cause first. Thawing the coil without fixing the underlying problem just lets it refreeze within days.
Should I repair or replace a leaking evaporator coil?
Depends on system age and refrigerant type. Under 8 years old on R-410A or A2L: repair almost always wins. 10 or more years old: repair often makes economic sense for one leak, but recurring leaks suggest replacement. R-22 systems with major leaks: replacement usually wins because R-22 currently runs $190-$260 per pound. We show you the side-by-side math during the diagnostic.
Why does my house smell like mildew when the AC runs?
Most common cause: biofilm buildup on the wet evaporator coil surface. The coil pulls humidity out of indoor air, and that water on the aluminum fins becomes a perfect substrate for bacterial and mold growth. Cleaning the coil eliminates the smell within 48-72 hours. For chronic cases, UV-C light installation near the coil ($245-$485) prevents recurrence.
Ready to Book Your AC Maintenance? Call Above & Beyond Today
A real San Antonio team member answers, never a phone tree. Free written estimate before any work. TDLR Class A licensed, $20M general liability, 30 years in the SA trade.
(210) 897-8658
Same-Day Capacitor Replacement
Monday through Friday: 7:00 AM to 7:00 PM | Saturday: 8:00 AM to 5:00 PM | Sunday: Emergency Dispatch Only | After-Hours Emergencies: 24/7, call (210) 837-1466