HVAC Not Working in Lafayette? Here Is What to Check Right Now

It is a hot summer afternoon in Lafayette, Louisiana, and your HVAC is not working. The house is getting warmer by the minute, and you have no idea what is wrong. Sound familiar? You are not alone.

In Lafayette, where summer temperatures regularly climb past 95°F, and the humidity makes it feel even hotter, a broken HVAC system is not just uncomfortable; it can be dangerous. The good news is that many of the most common HVAC problems have simple causes, and some of them you can fix yourself in just a few minutes.

In this guide, the team at Fontenot Air Conditioning and Heating walks you through the 10 most common reasons your HVAC system stops working, how to troubleshoot each one, and exactly when it is time to call in a professional HVAC technician.

��  Quick Answer: Why Is My HVAC Not Working?The most common reasons an HVAC system stops working are: a dirty air filter, a tripped circuit breaker, thermostat issues, low refrigerant, frozen evaporator coils, a clogged condensate drain, or a faulty capacitor. Start by checking your thermostat settings and your circuit breaker panel; these two quick checks resolve over half of all HVAC no-power calls in Lafayette.

Start Here: 3 Quick Checks Before Anything Else

Before you panic or call anyone, run through these three fast checks. They take less than five minutes and solve more HVAC problems than you might think.

1. Check Your Thermostat Settings

This sounds obvious, but it is the number one thing homeowners overlook. Your thermostat might be set to the wrong mode (heat instead of cool), the temperature might be set too high, or the batteries might simply be dead.

What to do: Check that the mode is set to COOL (in summer) or HEAT (in winter), the set temperature is lower than the current room temperature, and the fan is set to AUTO. If the screen is blank, replace the batteries first.

2. Check Your Circuit Breaker

Your HVAC system has its own dedicated circuit breaker, sometimes two (one for the indoor unit, one for the outdoor unit). A power surge, a storm, or an overloaded circuit can trip the breaker, which completely cuts power to the system.

What to do: Go to your electrical panel and look for any breaker that is in the middle or OFF position. Flip it fully off, then back on. Important: if it trips again immediately, do NOT keep resetting it. That signals a deeper electrical problem; call a professional.

3. Check the Emergency Shutoff Switch

Most HVAC systems have a secondary power switch, which looks like a regular light switch, usually located near the indoor air handler in your attic, closet, or utility room. It is easy to accidentally switch this off.

What to do: Find the switch near your indoor unit and make sure it is flipped to ON.

��  Lafayette Tip from Fontenot AirDuring Lafayette’s storm season, tripped breakers are extremely common. After any heavy thunderstorm, the first thing to check is always your circuit breaker panel before calling for HVAC repair.

10 Common Reasons Your HVAC Is Not Working (With Fixes)

If the quick checks above did not solve your problem, one of these ten issues is almost certainly the culprit. We have listed them from the most common to the least common based on what our technicians see most often at service calls across Lafayette.

Reason 1: Dirty or Clogged Air Filter

A dirty air filter is the single most common cause of HVAC problems, and the easiest to fix. When the filter gets clogged with dust, pet hair, and debris, air cannot flow through the system properly. This leads to reduced cooling, higher energy bills, and eventually a complete shutdown.

Symptoms: Weak airflow from vents, HVAC running but not cooling, system turning on and off repeatedly, or ice forming on the indoor unit.

DIY Fix: Turn off your system, locate the filter (usually in the return air vent or inside the air handler), pull it out, and hold it up to a light. If you cannot see light through it, replace it. Filters in Lafayette homes typically need replacing every 30 to 60 days due to high dust and pollen levels.

✅  Filter Replacement Quick Guide1-inch filters: Replace every 30–60 days4-inch filters: Replace every 6–12 monthsHEPA filters: Replace every 12 monthsHomes with pets or allergies: Replace more frequently

Reason 2: Thermostat Problems

Beyond the basic setting checks above, your thermostat itself could be malfunctioning. This is especially common with older thermostats or smart thermostats that have lost their Wi-Fi connection.

Symptoms: The display is blank or frozen, the system does not respond to temperature changes, or the HVAC runs constantly without reaching the set temperature.

DIY Fix: For standard thermostats, replace the batteries and check the wiring connections at the back. For smart thermostats (like Nest or Ecobee), check your Wi-Fi connection and try a factory reset. If the problem persists, the thermostat may need to be replaced, a relatively affordable fix.

Reason 3: Tripped Circuit Breaker or Blown Fuse

We covered this in the quick checks, but it is worth going deeper. A breaker trips as a safety mechanism. If yours keeps tripping after you reset it, your HVAC system may be drawing too much electricity, which points to a failing motor, a short circuit, or a compressor problem.

DIY Fix: Reset once. If it trips again, stop and call a professional. Repeatedly resetting a tripping breaker can damage your system and create a fire hazard.

Reason 4, Low or Leaking Refrigerant

Refrigerant (commonly called Freon, though newer systems use R-410A) is the substance that actually cools the air in your home. Your HVAC system is a closed loop; refrigerant does not get “used up” like gas. If levels are low, it means there is a leak somewhere in the system.

Symptoms: HVAC is running but only blowing warm air, you hear a hissing or bubbling sound near the outdoor unit, or you see ice forming on the copper refrigerant lines.

Fix: This is NOT a DIY repair. Handling refrigerant requires EPA Section 608 certification. A licensed technician needs to find the leak, repair it, and then recharge the system. Skipping the leak repair and just adding refrigerant is a temporary fix that will fail again quickly.

⚠️  Important: Do Not Ignore Refrigerant LeaksIn Lafayette’s heat, running your system with low refrigerant can permanently damage the compressor, the most expensive part of your HVAC system. If you suspect a refrigerant leak, turn the system off and call Fontenot Air Conditioning and Heating right away.

Reason 5, Frozen Evaporator Coils

The evaporator coil inside your air handler absorbs heat from the indoor air. If airflow is restricted (usually from a dirty filter or low refrigerant), the coil gets too cold and literally freezes up, blocking all air exchange.

Symptoms: Little to no airflow from vents, warm air despite the system running, visible ice on the indoor unit or the refrigerant lines, or water pooling around the unit as ice melts.

DIY Steps:

1. Turn the thermostat to OFF (not just FAN).

2. Switch the fan to ON so it can circulate warm air over the coils.

3. Let it thaw completely; this can take 2 to 24 hours.

4. Replace the air filter while you wait.

5. Once thawed, turn the system back on and monitor it.

6. If it freezes again within a day, call a professional; you likely have a refrigerant leak.

Reason 6 Dirty Condenser Coils (Outdoor Unit)

Your outdoor unit releases the heat that was pulled from inside your home. The condenser coils do this work, but over time, they get coated with dirt, grass clippings, cottonwood seeds, and grim, especially in Lafayette’s humid environment. Dirty coils cannot release heat efficiently, causing the system to overheat and shut down.

Symptoms: HVAC runs constantly but cannot reach the set temperature, the outdoor unit feels extremely hot to the touch, or the system keeps shutting off.

DIY Fix: Turn the system off at the breaker. Clear any vegetation or debris from around the unit (maintain at least 2 feet of clearance on all sides). Using a garden hose on a gentle setting, rinse the coils from the inside out. Never use a pressure washer; the fins bend easily. Schedule a professional coil cleaning once a year for best results.

Reason 7, Faulty Capacitor or Fan Motor

The capacitor is the component that gives your HVAC’s motors the initial burst of electricity needed to start up. Over time, especially with Lafayette’s heat and long cooling seasons, capacitors wear out and fail.

Symptoms: You hear the outdoor unit humming, but the fan is not spinning, the system tries to start but shuts off immediately, or you notice a clicking sound when the system tries to turn on.

Fix: This requires a professional. Capacitors store a large electrical charge even when the power is off; they can cause a serious shock if mishandled. Capacitor replacement is typically an affordable repair ($150–$400), and a technician can usually complete it in under an hour.

Reason: Clogged Condensate Drain Line

As your HVAC cools the air, it also removes humidity, which is especially important in Lafayette. That moisture drips off the evaporator coil, collects in a drain pan, and exits through a PVC condensate drain line. In Louisiana’s humidity, this line can clog with algae, mold, and sludge within weeks.

Symptoms: Water dripping or pooling around the indoor unit, musty smell from the vents, or the system shuts off on its own (the safety float switch trips when the drain pan overflows).

DIY Fix: Find the white PVC drain line near your indoor unit. Pour a cup of diluted white vinegar (or a bleach-water mix) down the drain line access port monthly. If clogged, use a wet-dry vacuum at the outdoor end of the drain line to suck out the blockage.

��  Lafayette Monthly Maintenance TipBecause of our extreme humidity, condensate drain clogs are far more common in Lafayette than in drier climates. Fontenot Air recommends pouring a cup of diluted bleach down your condensate drain line every month during the cooling season to prevent algae buildup.

Reason 9, Ignition or Pilot Light Failure (Furnaces and Heat Pumps)

If your HVAC is not working in heating mode, the problem may be with the ignition system, burners, or flame sensor in your furnace.

Symptoms: The system runs but blows cold air in heating mode, you hear clicking without ignition, or the furnace shuts off shortly after starting.

Fix: Do not attempt to repair gas components yourself. A faulty ignition on a gas furnace can create a gas leak or carbon monoxide risk. Call a certified HVAC technician to inspect the flame sensor, ignitor, and burners.

Reason 10 System Age or Lack of Maintenance

Sometimes, an HVAC system is not working because it is simply at the end of its life. The average central AC unit lasts 10 to 15 years in Louisiana’s demanding climate. Furnaces last 15 to 20 years. If your system is older and requires frequent repairs, the cost of continuing to fix it may exceed the cost of replacement.

Use the 5,000 Rule: Multiply the cost of the repair by the age of the system. If the result is more than $5,000, it is usually smarter to replace than repair. For example, a $300 repair on a 10-year-old system = $3,000, so repair it. A $400 repair on a 15-year-old system = $6,000; consider replacement.

HVAC Not Working? Troubleshoot by What You Are Experiencing

Not sure which of the above applies to you? Use your symptoms to narrow it down.

Symptom	Most Likely Cause(s)
HVAC is running but not cooling	Dirty filter, low refrigerant, frozen coils, dirty condenser coils
HVAC is not turning on at all	Tripped breaker, dead thermostat batteries, blown fuse, faulty capacitor
HVAC blowing warm air	Thermostat set to HEAT or FAN-only, low refrigerant, dirty condenser
HVAC keeps turning off (short cycling)	Clogged filter, frozen coils, oversized unit, thermostat placement near heat source
HVAC is making a loud noise	Loose parts (banging), refrigerant leak (hissing), motor failure (grinding/squealing)
HVAC is not blowing air at all	Blower motor failure, blocked return vents, disconnected ductwork
Water is leaking from the indoor unit	Clogged condensate drain, frozen coils thawing, and cracked drain pan
Musty smell from vents	Mold or algae in the drain pan or ducts isvery common in Lafayette’s humidity
High energy bills, no other symptoms	Dirty coils, low refrigerant, failing capacitor, duct leaks, aging system

What You Can Fix Yourself vs. What Needs a Professional

Here is a simple breakdown to help you decide when to grab a screwdriver and when to pick up the phone.

Task	DIY or Call a Pro?
Replace the air filter	DI, Do this every 30–60 days
Reset circuit breaker (once)	DIY Quick and safe
Replace thermostat batteries	DI , 2-minute task
Clear debris from the outdoor unit	DIY, Monthly/seasonal
Unclog the condensate drain line	DIY, with vinegar or a wet vac
Thaw frozen evaporator coils	DIY, turn to fan mode, and wait
Refrigerant recharge or leak repair	PRO ONLY, Requires EPA certification
Capacitor or fan motor replacement	PRO ONLY, Electrical safety risk
Ignition or flame sensor repair	PRO ONLY, Gas safety risk
Ductwork sealing or replacement	PRO ONLY Needs specialized tools
Compressor repair or replacement	PRO ONLY, Complex, expensive

How to Prevent HVAC Problems in Lafayette (Seasonal Checklist)

The best way to avoid an HVAC breakdown in Lafayette’s extreme heat is to stay ahead of problems with regular maintenance. Here is what Fontenot Air recommends:

Every Month (Cooling Season)

• Check and replace the air filter if dirty

• Pour diluted bleach or white vinegar down the condensate drain line

• Check that the outdoor unit is clear of grass, vines, and debris

Every Spring (Before Cooling Season Starts)

• Schedule a professional AC tune-up with Fontenot Air Conditioning and Heating

• Clean evaporator and condenser coils

• Test thermostat calibration

• Check refrigerant levels

• Inspect all electrical connections

• Check and clean the condensate drain pan

Every Fall (Before Heating Season)

• Schedule a furnace or heat pump inspection

• Replace air filter

• Test heating mode on thermostat

• Check burners, ignition, and flame sensor

• Inspect the heat exchanger for cracks

Every Year

• Have ductwork inspected for leaks. Duct leaks in Lafayette homes can waste 20–30% of conditioned air

• Check insulation around refrigerant lines

• Test carbon monoxide detectors

How Much Does HVAC Repair Cost in Lafayette, LA?

Repair costs vary depending on the issue, the brand of your system, and the time of the service call. Here are typical HVAC repair costs in the Lafayette area:

Repair Type	Estimated Cost (Lafayette Area)
Air filter replacement	$10–$40 (DIY) or included in a tune-up
Thermostat replacement	$150–$500 including labor
Capacitor replacement	$150–$400
Condensate drain cleaning	$75–$200
Refrigerant recharge (R-410A)	$250–$600+ (plus leak repair)
Evaporator coil cleaning	$100–$400
Condenser coil cleaning	$75–$300
Fan motor replacement	$300–$700
Compressor replacement	$800–$2,800
Full system replacement (AC)	$3,500–$8,000+ installed

Note: These are estimates. Actual costs depend on your system brand, model, and the time of service. Fontenot Air Conditioning and Heating offers upfront pricing; you will always know the cost before any work begins.

Frequently Asked Questions About HVAC Not Working

Dealing with a Bigger HVAC Emergency in Lafayette?

Sometimes an HVAC problem cannot wait, especially in the middle of a Louisiana summer when indoor temperatures can become unsafe within hours. If you are dealing with a complete HVAC failure, a refrigerant leak, or a furnace that will not start, you need more than troubleshooting tips.

��  Get Emergency HVAC Help in LafayetteFontenot Air Conditioning and Heating provides emergency HVAC service throughout Lafayette and the surrounding Acadiana area. Whether it is the middle of the night or a holiday weekend, our certified technicians are ready to respond. → Learn more: Emergency HVAC Service in Lafayette [INTERNAL LINK TO PILLAR PAGE] Do not let a broken HVAC system put your family at risk in Lafayette’s heat. Call Fontenot Air. We have been serving Lafayette homeowners and businesses for years, and we stand behind every repair we make.

Conclusion: Get Your HVAC Working Again

HVAC not working is one of the most stressful problems a Lafayette homeowner can face, but in most cases, it does not have to stay broken for long.

Start with the basics: check your thermostat, flip your circuit breaker, and look at your air filter. These three steps alone will fix more than half of all HVAC calls. If those do not solve it, work through the 10 common causes in this guide, from frozen coils and clogged drains to a failing capacitor or low refrigerant.

And remember,r when the problem is beyond a DIY fix, Fontenot Air Conditioning and Heating is right here in Lafayette. Our team knows this climate, knows the challenges Louisiana homes face, and is ready to get your system running again fast.

��  Contact Fontenot Air Conditioning and Heating, Lafayette, LAServing Lafayette and the Acadiana areaLicensed, certified HVAC techniciansUpfront pricing, no surprisesEmergency HVAC service available→ [INSERT PHONE NUMBER AND BOOKING LINK HERE]