When it's 102° outside and your AC is running but not cooling, you need answers fast. Here's what's usually wrong, what it costs to fix in Dallas, and when to take the repair-or-replace question seriously.
Get Repair Bids from DFW ContractorsCheck the filter first. A clogged air filter is the most common cause of reduced cooling and costs nothing to fix. If it's gray and matted, replace it and give the system 30 minutes to recover before calling anyone.
Check the thermostat. Make sure it's set to COOL, not FAN. Make sure the set temperature is below the current indoor temperature. This sounds obvious but it's a real call contractors get.
Look at the outdoor unit. Is it running? If the indoor air handler is blowing but the outdoor condenser isn't running, you likely have an electrical issue — capacitor, contactor, or breaker. This is often a $150–$400 fix.
Check for ice. If you see frost or ice on the refrigerant lines or on the indoor coil, turn the system off immediately and let it thaw. Running a frozen system damages the compressor. See the section on frozen coils below.
If none of those apply, the causes below are ranked from most common and cheapest to less common and more expensive. Most AC problems in Dallas fall into the first three categories.
These cover the majority of AC not-cooling calls in DFW. The ranking reflects both frequency and repair cost — the cheap ones fail more often and are easier to diagnose.
A dirty filter restricts airflow across the evaporator coil. The coil can't absorb heat properly, the system runs longer without cooling the space, and in bad cases it freezes entirely. Dallas systems run hard and filters need changing more frequently than the packaging suggests — every 4–6 weeks during peak season for standard 1-inch filters, not the advertised 90 days.
Capacitors are small cylindrical components that help start and run the compressor and fan motors. Contactors are the electrical switches that send power to the outdoor unit. Both fail regularly in Dallas — the heat accelerates wear, and these parts are on almost every AC service call during summer.
Signs: the outdoor unit isn't running even though the indoor air handler is blowing. Or you hear a humming sound from outside but the fan isn't spinning. These are cheap parts and quick fixes — usually diagnosed and resolved in a single visit.
Refrigerant doesn't get consumed — if you're low, there's a leak somewhere. A simple recharge without finding and fixing the leak is a temporary fix that will leave you in the same spot next summer. Costs vary widely: a straightforward recharge on a system without a detectable leak runs $200–$500. Finding and repairing a leak adds $300–$800. A leak in the evaporator coil that requires coil replacement can run $800–$1,800.
Signs: the system runs but the air coming out isn't cold, or it cools fine on mild days but struggles when it's really hot outside. Ice on the refrigerant lines is also a sign of low charge.
The evaporator coil (inside the air handler) can freeze when airflow is restricted — usually from a dirty filter or closed vents — or when refrigerant is low. A frozen coil blocks airflow entirely and the system effectively stops cooling even though it's running.
The ice itself isn't the problem — it's a symptom. Turn the system off and let it thaw completely (a few hours to overnight). Then address the cause: replace the filter, open any closed vents, and if it freezes again, have a tech check refrigerant levels.
The outdoor condenser unit releases heat from your home to the outside air. If the coil fins are clogged with dirt, cottonwood, grass clippings, or debris, it can't shed heat efficiently — especially problematic in a Dallas summer when it's already trying to dump heat into 105° air. A coil cleaning typically restores full capacity.
In Dallas, condenser coils in yards with cottonwood trees or near landscaping can clog within a single season. Annual cleaning during a spring tune-up is cheaper than the diagnostic visit you'd need in July.
The indoor blower motor moves air across the evaporator coil and into your home. The outdoor fan motor draws air across the condenser. Either can fail — bearings wear out, windings burn, capacitors that support them fail. Signs include the system running but no airflow from vents, or the outdoor unit running but the fan not spinning.
Motor replacements are a moderate repair. On a newer system they're straightforward fixes. On a 12+ year old system they raise the question of whether a larger repair is around the corner.
The compressor is the heart of the refrigeration cycle — it pressurizes the refrigerant so the system can move heat. When it fails, the system runs but produces no cooling whatsoever. Signs: outdoor unit is running (fan spinning, power on) but no cooling at all and no cold refrigerant lines.
Compressor replacement is expensive and raises a serious repair-vs-replace question, especially on systems over 10 years old. The repair cost alone ($1,200–$2,500) may be 30–50% of what a replacement would cost. Before approving a compressor replacement, get a replacement bid to run the math properly.
The evaporator coil (inside the air handler) can develop refrigerant leaks due to formicary corrosion — a reaction between copper coil material, moisture, and airborne contaminants. This is more common in certain geographic areas and in homes with VOC exposure (cleaning products, off-gassing materials). Signs: repeated refrigerant loss with no detectable leak in the linesets, or low refrigerant that keeps returning.
Coil replacement is a significant repair. The coil itself runs $400–$1,000 depending on brand and size; labor adds $400–$800. Total can approach $1,800 or more. At this cost on an older system, replacement comparison is almost always worth doing first.
These are typical ranges for Dallas-area repair calls. Actual cost depends on the specific brand, part availability, labor time, and whether additional issues are found during the visit. For context on full replacement pricing, see our HVAC replacement cost guide for Dallas.
| Repair | Typical DFW Cost | Notes |
|---|---|---|
| Air filter replacement | $5–$30 | DIY. Do this before calling anyone. |
| Capacitor replacement | $150–$350 | Common summer failure. Quick fix. |
| Contactor replacement | $150–$300 | Often replaced alongside capacitor. |
| Refrigerant recharge (no leak found) | $200–$500 | Temporary if leak source isn't addressed. |
| Refrigerant leak repair + recharge | $400–$1,200 | Cost varies by leak location. |
| Condenser coil cleaning | $150–$350 | Often part of annual tune-up. |
| Blower motor replacement | $400–$900 | Raises replacement question on older units. |
| Evaporator coil replacement | $800–$2,000 | Compare to replacement cost before approving. |
| Compressor replacement | $1,200–$2,500+ | Almost always compare to full replacement first. |
| Full system replacement (3-ton mid-tier) | $6,000–$9,000 | Context for the math on major repairs. |
Diagnostic fees ($75–$150) are typically charged separately and sometimes credited toward the repair. Ask upfront.
Before approving a major repair, see what a replacement would cost. VentBid matches you with licensed DFW contractors who itemize equipment and labor separately.
Request a Match — It's FreeMost AC problems are repairs. But a few situations genuinely shift the math toward replacement — and it's worth knowing them so you can evaluate a contractor recommendation honestly rather than just reacting to the diagnosis.
A compressor replacement on a 12-year-old Dallas unit costs $1,200–$2,500. A new mid-tier system might run $7,000–$9,000 installed. The repair is 15–30% of replacement cost — which sounds like a clear repair case, until you factor in that the system has likely already had its best years in Dallas heat. You're paying $2,000 to potentially get 2–4 more summers from a system that's going to need more repairs.
This is one of the cleaner cases where getting a replacement bid alongside the repair quote — before approving anything — is genuinely valuable. You might still choose the repair, but you'd be making that decision with real numbers on both sides.
A system that needed a $600 repair last summer and now needs $1,000 more isn't just unlucky. Aging HVAC systems often decline in clusters — one component failure stresses others. Two or three major repairs within a few years is a pattern worth taking seriously, even if each individual repair technically "pencils out."
If you're recharging refrigerant every year and the leak source hasn't been found and fixed, you have an ongoing problem that's also potentially a coil replacement conversation. Continuing to recharge without addressing the source isn't maintenance — it's deferral.
A system that cools adequately on 85° days but can't keep up at 103° is either undersized, significantly low on refrigerant, or showing compressor decline. In Dallas, where you routinely hit 100°+ from June through September, a system that can't perform at those temperatures isn't really doing its job.
For a more detailed walkthrough of this decision, see our HVAC Repair vs. Replace guide for Dallas homeowners.
When a contractor diagnoses your AC, the information they give you shapes a decision that could cost anywhere from $200 to $10,000. Understanding the common patterns helps you ask better questions.
Some contractors will recommend full replacement on a system that could be repaired — particularly when the repair involves a component they don't stock or when the replacement margin is appealing. This isn't always bad advice, but it deserves scrutiny.
What to ask: "What specifically failed? What would it cost to repair just that component? And what would a comparable replacement cost?" If the contractor can answer those three questions clearly, you can evaluate the recommendation. If they can only give you the replacement number, that's a yellow flag.
Adding refrigerant without finding the leak source treats the symptom, not the problem. You'll be in the same position next summer. Ask explicitly: "Did you find where the refrigerant went? What's the source of the loss?"
A $100–$150 diagnostic fee is reasonable and standard. Some contractors waive it if you proceed with the repair — which is fine. What to watch for: a diagnostic visit that quickly turns into a $3,000 recommendation without a clear itemized breakdown of what's failing and what each component costs.
"I can have a new unit in tomorrow but I need your decision today" is a pressure tactic more often than a genuine logistics constraint. Equipment availability is real during peak season — but a reputable contractor will give you time to think through a major decision, even if they're busy.
If your AC isn't cooling and the diagnosis is pointing toward a repair over $800, the most useful thing you can do before approving it is get a replacement quote that shows equipment and labor on separate lines. That gives you the real denominator for the repair-vs-replace math.
VentBid connects Dallas-area homeowners with licensed local contractors who submit bids with equipment cost and labor cost shown separately. When you're deciding whether a $1,500 repair makes sense, knowing that a full replacement would run $7,500 — broken out clearly — is the information you actually need to make a good call.
VentBid is still early, but the core idea is simple: help homeowners get clearer bids from local contractors without the usual back-and-forth. There's no cost to homeowners to request a match. If you want to compare real itemized bids from licensed Dallas contractors, you can request matches here.
Request a MatchYou don't have to have already decided to replace. Requesting a bid is just getting information — and it's the information that makes both the repair and the replacement decision cleaner.
See what repair and replacement would actually cost — equipment and labor on separate lines — before approving anything major.
Request a Match — It's FreeCommon questions from DFW homeowners dealing with an AC that isn't cooling.