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AC Not Cooling?

• TDLR License TACLB00018282E
• Family-owned since 2004 · Plano, TX
• ★★★★★ 4.7 rating · 457+ reviews
• 5-Year Parts Warranty (Comfort Club, viable systems)
• 7 days a week · same-day service most days

Call Randy & Teresa’s Team — (972) 398-6151

What “Running But Not Cooling” Means

“Running but not cooling” means the AC is on, the box outside hums, and the fan inside blows — but the air from the vents is not cold. This is not the same as an AC that will not turn on at all. Something is stopping the cold part, but the power is fine.

This matters a lot in Texas. The U.S. Energy Information Administration reports that AC is the biggest single use of home electricity in the South.^[1] A unit that runs but does not cool wastes that power.

The good news: most causes are simple, cheap, and fixable in 30 minutes with no tools. A few get worse the longer you run the AC, so before you call anyone — even us — check these 7 things.

If your AC has ice on it right now, jump to step 5. Otherwise, start at the top.

The 7 Things to Check Before You Call

1. Pull out the air filter

The filter is the rectangle of fluffy material in a slot near your AC or thermostat. Pull it out and hold it up to a light. If you cannot see light through it, that is almost surely your problem.

A dirty filter blocks air. When air cannot flow, the cold part inside (called the coil) gets too cold and freezes over. A frozen coil cannot cool your house.

The U.S. Department of Energy says a clean filter can cut your AC’s power use by 5% to 15%. In a Plano summer running 12+ hours a day, that is real money — and often the difference between cool air and warm air.

If the filter is gray, fuzzy, or you cannot see through it, swap it for a new one and wait 30 minutes.

2. Check the thermostat

Walk to your thermostat. Check three things in this order:

• Mode. Make sure it says “Cool.” Not “Off,” “Fan,” or “Heat.” Sounds silly. Happens a lot.
• Set point. Set it at least 5 degrees lower than the room is right now. If the room is 78 and you set it to 76, the AC may have already shut off because it thinks it is done.
• Batteries. Many thermostats run on AA or AAA batteries. Pop the cover and check — weak batteries cause odd problems before they fully die.

If the screen is blank or shows a warning, start there. Do not look at the AC yet.

3. Check the breaker

Walk to your home’s electrical panel — the gray metal box on a wall in your garage, basement, or laundry room. Look for a switch labeled “AC,” “A/C,” “Air Conditioner,” “Compressor,” or “Air Handler.” There may be two: one inside, one outside.

If a switch is sitting in the middle (not fully on, not fully off), it is “tripped.” Push it all the way to “Off,” wait 5 seconds, then push it firmly to “On.”

If it trips again right away, stop. Forcing the breaker can damage the big motor (called the compressor), which is a costly part. Call us instead.

4. Look at the outdoor unit

Go outside to the big metal box on the side or back of your house (called the condenser). While the AC is on, you should see and hear two things:

• The fan on top is spinning.
• A low hum from inside the box.

If you hear the hum but the fan is not spinning, the fan motor or a small part called a capacitor is failing. Time to call. If you hear nothing at all but the breaker is on, also call us.

If both are running and the unit just feels hot, clear away any leaves, grass, or fluffy seeds blocking the metal fins on the sides. Stuff stuck there blocks airflow and weakens cooling.

5. Look at the indoor unit for ice

The indoor unit (called the air handler) is usually in the attic, a closet, or the garage. Look at the bigger copper pipe going into it. If you see frost or ice on the pipe — or a sheet of ice on the coil — the system is frozen.

Right now: turn the AC off at the thermostat and set the fan to “On” (not “Auto”). The fan helps the ice melt faster. Wait at least 4 hours.

If you keep running a frozen AC, it can break the compressor — a $1,800+ part. The thaw is the cheap fix. While it thaws, swap the filter for a clean one (a dirty filter is the most common reason coils freeze).

6. Listen for a click outside

Stand next to the outdoor unit. Have someone drop the thermostat 5 degrees. You should hear a soft click within 30 seconds — a small switch (called a contactor) turning on. If you hear nothing, the wires that tell the AC to start are not working. Call us.

7. Check the vents

Walk every room. Make sure all the vents are open. Move any furniture, rugs, or laundry baskets away from the big return-air vent (the bigger grille, often in a hallway). Closed vents and blocked returns drop cooling in every room, not just the closed one.

When to Stop and Call

Some signs are not worth a second try. If any of these are happening, stop and call — running longer makes it worse:

• The breaker trips again every time you flip it back on.
• The outside unit is silent (no fan, no hum) but the breaker is on.
• The outside unit runs but the air inside is still warm, even after a clean filter.
• There is still ice on the pipe after a 4-hour thaw with the AC off.
• You smell anything burning, electrical, or chemical near either unit.
• The thermostat shows an error code and will not reset.

Those six are real call-the-pros moments. Anything else can wait for same-day service if you call before noon. We answer 7 days a week.

When you call (972) 398-6151, have your address, AC brand, and rough age ready. We will usually tell you the likely fix on the phone before sending a truck. See our AC repair page or book online at schedule in about 90 seconds — that unlocks the $50 first-time rate.

What a 1st Class Visit Looks Like

We are a family-owned HVAC shop in Plano. Randy and Teresa Lazenby started it in 2004. Our state license is TACLB00018282E. We only do home heating and cooling — no plumbing, no electrical, no upsells you do not need.

A service call with us looks like this:

• $99 for the visit ($50 the first time when you book online).
• The check-up is included — no extra “just to look” fee.
• We hand you a written, line-by-line price before any work starts.
• 5-Year Parts Warranty if your system can be saved and you are an active Comfort Club member — the longest in DFW for homes.
• 7 days a week. Same-day service for calls before noon.
• No extra evening or weekend fees for Comfort Club members.

One thing to know about older AC units: in January 2023 the U.S. Department of Energy raised the rules for new AC units in the South (which includes Texas) to a higher energy score called 14.3 SEER2.^[2] Units 12+ years old can often be repaired, but cannot always be brought up to today’s rules. We will lay out the repair-or-replace math in writing first. No surprises.

How a Comfort Club Tune-Up Catches This Early

A dirty filter, low refrigerant, a slow-failing capacitor — each one drops hints for weeks before it leaves you stuck in a hot house at 3 PM in July. A spring tune-up catches those hints early.

Our Comfort Club is $29.95 a month. You get 2 tune-ups a year (spring AC + fall furnace, about $200 separately), 15% off all repairs, your emergency rate drops from $189 to $99, priority scheduling in July and January, and no extra evening or weekend fees.

If a Comfort Club tune-up had caught this, you would be paying $99 instead of $189 — or nothing, because we would have spotted it last spring.

For more on clean air at home: Indoor Air Quality FAQs.

Frequently Asked Questions

How long should I wait after a new filter?

Wait 30 minutes with the AC running. If the air from the vents is clearly cooler, the filter was the problem. If it still feels warm, move to the next check. If you saw ice, wait 4 hours with the AC off and fan on first.

My AC has ice on it. Can I keep running it to melt the ice?

No. A frozen AC pushes liquid back into the compressor (the big motor) and ruins it. A new compressor is $1,800+. Turn the AC off at the thermostat, set the fan to “On” (not “Auto”), and wait at least 4 hours before testing. A dirty filter is the most common cause, so swap it during the wait.

Can I add the cold gas (refrigerant) myself?

No. Federal law (the EPA’s Section 608 rule) says only certified pros can handle refrigerant. The older gas (R-410A) is also being phased out in 2025 for a new one (R-454B), and the two cannot be mixed. If your AC is low on gas, the leak also has to be found and fixed.

What does an AC service call cost in DFW in 2026?

Our standard home service call is $99 ($50 the first time if you book online). Emergency after-hours calls are $189 for non-members and $99 for Comfort Club members. The check-up is included — no extra fee just to look. If you say yes to the repair right then, we waive the service call.

Do you offer same-day service in Plano, Frisco, McKinney, and Allen?

Yes. Same-day is available 7 days a week for calls before noon, based on our schedule. We have served all four cities since 2004 from our Plano shop. After-noon calls are usually next morning.

How can I check your TDLR license before I let a tech in my house?

Smart move. Our license is TACLB00018282E. Check it free on the state’s site: Texas Department of Licensing and Regulation. Every real Texas HVAC company has one. If a contractor will not give you theirs, that is your answer.

Where We Got Our Numbers

Here are the trusted sources we used in this post. You can click each one to read or verify what we cited.

1. U.S. Energy Information Administration (EIA) — the federal agency that tracks how much energy U.S. homes use. Their home survey is called the Residential Energy Consumption Survey. It is where the “AC is the biggest electricity use in the South” finding comes from.
2. U.S. Department of Energy (DOE) — the federal agency that sets the rules for AC efficiency. Their plain-English homeowner guides: Air Conditioner Maintenance and Common AC Problems. The 2023 rule for new AC units in the South (14.3 SEER2 minimum) lives in federal regulation 10 CFR Part 430.
3. U.S. Environmental Protection Agency (EPA) — the federal agency that regulates the cold gas (refrigerant) in your AC. Their Section 608 program is the law that says only certified pros can handle it.
4. Texas Department of Licensing and Regulation (TDLR) — the state agency that licenses HVAC contractors in Texas. Verify any contractor’s license here: License Verification.