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San Antonio · AC Capacitor Repair · Family-Owned Since 1996

Your AC Won't Start? It's Almost Always the Capacitor.

If your outdoor unit is humming but the fan isn't spinning — or it kicks on for a few seconds and quits — a $25 capacitor is the part that died. Most San Antonio capacitor jobs are done in under an hour.

Typical price

$180–$280 installed

Time to fix

30–60 minutes

Urgency

High — don't run it

In plain English — what's going on with your ac capacitor

A capacitor is a little can-shaped battery bolted inside your outdoor AC unit. Its only job is to give the motors (the compressor and the fan) a hard electrical kick to get them spinning, then keep them running smoothly.

In San Antonio heat, capacitors are the #1 part that fails — usually after 5 to 7 years. When one weakens, your AC starts struggling. When it dies completely, the unit just hums or clicks and shuts off. The repair is genuinely simple: the part itself is $15–$40 wholesale, and a good tech can swap it in 20 minutes.

Because the job is so quick, this is also the repair most companies try to mark up the hardest. We charge $180–$280 all-in. If anyone quotes you $500+ for 'a capacitor and a check,' get a second opinion.

What it costs in San Antonio

$180–$280 installedIncludes the part, labor, and a system check. No surprise fees. Our $59 diagnostic is waived when you approve the repair, so you only pay for the fix itself.

Symptoms you'll notice at home

If two or more of these sound familiar, it's probably your ac capacitor.

Outdoor unit hums but the fan doesn't spin
AC kicks on for 5–10 seconds, then shuts off
You hear a clicking sound from the outdoor unit
Warm air blowing from the vents on a 100° day
Bulging or leaking oil on top of the cylindrical part inside the disconnect box
Capacitor is more than 5 years old (San Antonio summers are brutal on them)

Why ac capacitors fail in San Antonio

  • Texas heat — San Antonio's 100°+ summers cook capacitors faster than almost anywhere else in the country.
  • Voltage spikes from CPS Energy grid surges, especially during August storms.
  • Age — most factory capacitors last 5 to 7 years here. Premium replacements last 10+.
  • Dirty condenser coils forcing the motors to work harder, which overloads the cap.
  • An undersized or wrong-microfarad capacitor installed by a previous tech.

How we diagnose and replace it

Here's exactly what a Carnes and Sons tech does at your house — no mystery, no upselling.

  1. 1

    Pull the disconnect and test with a multimeter

    We safely cut power, discharge the capacitor (it stores a lethal shock), and measure the microfarads against the rating printed on the can. Anything more than 6% below rated is failed.

  2. 2

    Inspect for physical failure

    A bulging top, oil residue, or burn marks means it's already blown. We also check the contactor right next to it — they often fail together in San Antonio heat.

  3. 3

    Match the exact microfarad and voltage

    We carry the common sizes (35/5, 40/5, 45/5, 55/5 MFD) on every truck. We install a 440V dual-rated cap even when the original was 370V — runs cooler, lasts longer.

  4. 4

    Test under load before we leave

    We re-energize the unit, watch the startup, measure amp draw on the compressor and fan, and verify supply-air temperature drop is at least 18°F. Then we show you the readings.

What Your Neighbors Are Saying

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AC Capacitor questions San Antonio homeowners actually ask

How much does a capacitor cost in San Antonio?

$180 to $280 installed, depending on the size and whether it's a single-run or dual-run capacitor. Our $59 diagnostic gets waived when you approve the repair, so that's your total out the door. Beware of anyone quoting $400+ for a basic capacitor — it's a 20-minute job.

Can I replace an AC capacitor myself?

Technically yes, but capacitors store enough charge to seriously hurt or kill you even with the power off. They have to be safely discharged with an insulated tool before you touch the terminals. We also see DIY swaps where the wrong microfarad was used, which fries the compressor — a $2,000+ mistake. For $180 it's not worth the risk.

How long does a new capacitor last?

A quality 440V dual-rated capacitor (what we install) lasts 8 to 12 years in San Antonio. Cheap units from a parts house can fail in 2 to 3 summers. We back ours with a 5-year parts warranty.

Why do capacitors fail so often in Texas?

Heat. Capacitors are rated for an internal temperature, and when your outdoor unit is sitting in 105° afternoon sun with the compressor running hot, the cap is the first thing to give up. Shade over the condenser, clean coils, and annual maintenance can double its life.

Should I run my AC if the capacitor is bad?

No. A weak or failing capacitor makes the compressor work harder, draw more amps, and run hotter — which can kill the compressor itself. A $200 capacitor failure can turn into a $2,500 compressor failure if you ignore it for a few weeks.

Can you come out today?

Yes — we keep same-day slots open every weekday for capacitor calls because they're the most common emergency. Text (210) 600-5091 and we'll give you a real arrival window.

Do you charge a service call fee?

$59 to diagnose. Waived entirely when you approve the repair. So if it's a capacitor and you say go, you only pay the repair price.

What's the difference between a single-run and dual-run capacitor?

A single-run capacitor powers one motor (fan or compressor). A dual-run capacitor powers both from one unit — it has three terminals (HERM, FAN, C). Most residential San Antonio systems use a dual-run. We carry both.

Do you warranty the part?

Yes — 5 years parts on the capacitor itself, and we stand behind the labor for 1 year. If the new cap fails inside 5 years, we replace it free.

Serving ac capacitor repairs across the greater San Antonio area

We're based in Stone Oak and roll trucks across San Antonio and the surrounding Hill Country every day.

Carnes and Sons Air Conditioning

License TACLB29435E · Family-Owned Since 1996

401 E Sonterra Blvd Suite 375
San Antonio, TX 78258
(210) 600-5091
Mon–Sat: 7AM – 8PM · Emergency same-day service

Cities & neighborhoods we serve

San Antonio · Stone Oak · Alamo Heights · Hollywood Park · Hill Country Village · Shavano Park · Castle Hills · Leon Valley · Helotes · Boerne · Fair Oaks Ranch · Bulverde · Timberwood Park · Garden Ridge · Schertz · Cibolo · Selma · Universal City · Live Oak · Converse · Windcrest · New Braunfels

Talk to a real person about your ac capacitor

No call center. The owner or one of his sons picks up.

(210) 600-5091