When the summer heat rolls through Cottonwood, AZ, the last thing you want is for your AC unit to run without actually cooling your home. If you’ve noticed that your air conditioner is humming along but the indoor temperature won’t budge, it can be frustrating—and uncomfortable. At Trio Cooling, Heating & Plumbing, we often get calls from homeowners asking why their AC unit is running but not cooling, and what they can do about it.

This issue can stem from a number of common problems, some of which you can troubleshoot yourself. In this post, we’ll cover what to check first, when to call a professional, and how to prevent it from happening again.

Check the Thermostat First

Before assuming the worst, take a moment to check your thermostat settings. Make sure it’s set to “cool” and not just “fan.” Sometimes, the thermostat might be set to a higher temperature than expected, or switched to a different mode.

It’s also a good idea to verify that the batteries are working (if your thermostat uses them) and that the display is functioning correctly. If the thermostat is malfunctioning, it won’t properly communicate with your AC unit—and that could be the entire problem.

AC Unit Running But Not Cooling? A Dirty Filter Could Be the Problem

A clogged or dirty air filter is one of the most common reasons an AC unit is running but not cooling. When the filter becomes blocked with dust, pet hair, or debris, it restricts airflow. As a result, your AC can’t circulate cold air effectively, even if the system is otherwise working.

Check your air filter and replace it if it looks dirty or hasn’t been changed in over a month. This simple fix can often restore proper airflow and cooling in minutes.

Outdoor Unit Not Functioning Properly

Head outside and inspect your outdoor condenser unit. Make sure it’s free from dirt, leaves, and obstructions. If the fan isn’t spinning or you hear unusual noises, it could indicate a problem with the motor, capacitor, or compressor.

Even if the indoor unit is blowing air, the outdoor condenser is responsible for actually removing heat from your home. If it’s not doing its job, your system can’t cool the air, no matter how long it runs.

AC Unit Running But Not Cooling Due to Low Refrigerant

Low refrigerant levels are another reason your AC unit is running but not cooling. Refrigerant is the chemical that absorbs and transfers heat. If your system is low—often due to a leak—it won’t be able to cool the air effectively.

Unfortunately, this isn’t something you can fix yourself. Handling refrigerant requires EPA certification, and leaks need to be located and sealed before recharging the system. If you suspect a refrigerant issue, call the professionals at Trio Cooling, Heating & Plumbing for a diagnosis and repair.

Evaporator Coil Could Be Frozen

If you’ve checked your filter and airflow still seems weak, a frozen evaporator coil may be to blame. When airflow is restricted or refrigerant is low, the coil can freeze up, preventing it from absorbing heat. You may even notice ice forming on the indoor unit or refrigerant lines.

Turn off the system to let it thaw, and avoid running the AC until the issue is resolved. If this happens repeatedly, it’s a sign that deeper issues are at play and you’ll need a technician to inspect the system.

Ductwork Leaks or Blockages

Even if the AC unit is functioning, cool air may not be reaching your living spaces if your ductwork has leaks or blockages. Over time, ducts can develop holes or become disconnected, especially in older homes in Cottonwood.

You might notice uneven cooling between rooms or hear whistling noises coming from the vents. A duct inspection can identify and resolve these hidden airflow problems.

AC Unit Running But Not Cooling? Electrical Issues May Be the Cause

Capacitors help start and run the motors that power your AC unit. If one fails, the system may power on but won’t actually cool the air. You might also experience intermittent cooling or hear a clicking noise when the system tries to start.

Since this involves working with high-voltage components, it’s best to leave the diagnosis and repair to qualified HVAC professionals like our team at Trio Cooling, Heating & Plumbing.

When to Call a Professional

While it’s helpful to perform basic checks on your own, many cooling issues require professional tools and training to fix properly. If you’ve changed the filter, checked the thermostat, and ensured the outdoor unit is clear—but your AC unit is running but not cooling—don’t wait for it to get worse.

Our licensed technicians can quickly diagnose the issue, whether it’s electrical, mechanical, or related to refrigerant. We serve homeowners across Cottonwood, Camp Verde, Village of Oak Creek, and surrounding areas with fast, reliable repairs that restore comfort fast.

How to Prevent Future Cooling Issues

Routine maintenance is the key to preventing cooling issues before they start. We recommend scheduling a professional AC tune-up at least once per year—ideally in the spring—so your system is ready to handle the heat.

During a tune-up, we:

• Clean and inspect the coils

• Check refrigerant pressure

• Test electrical components

• Replace filters if needed

• Ensure all parts are running at peak performance

This proactive care can help your system last longer, run more efficiently, and avoid surprise breakdowns during peak summer months.

Stay Cool with Trio Cooling, Heating & Plumbing

Dealing with an AC unit that’s running but not cooling is frustrating, but the solution may be simpler than you think. Whether it’s a clogged filter, frozen coil, or a more serious mechanical issue, the experts at Trio Cooling, Heating & Plumbing in Cottonwood, AZ are here to help.

We’ve been serving the Verde Valley with trusted HVAC and plumbing services built on honesty, integrity, and exceptional craftsmanship. When you need fast, effective AC repair, give our team a call—we’ll get your system back to peak performance so you can stay cool and comfortable all season long.