AC Not Cooling: Here’s How to Troubleshoot

Is there anything worse on a hot day than your air conditioner not cooling? As temperatures rise, you may notice your AC struggles to cool your home. Another common problem is when it's comfortable downstairs but hot upstairs. It can be frustrating and stress-inducing. Read below to learn why an air conditioner stops cooling, which problems you can solve yourself, and when to call a professional.AC not working? Change the filter!

Reasons An AC is Not Cooling

Low Refrigerant

Refrigerant is the key to cool air. It is what cools air before it enters your home.  A refill may be necessary due to low refrigerant levels. It may, however, have a leak. If there is a refrigerant leak, refilling it won't solve the problem. Therefore, a professional HVAC technician needs to take a closer look.

Faulty Coil

A faulty coil may be due to small leaks. These leaks are called formicary tunneling corrosion and are caused by moisture and VOCs in the air. VOCs stands for volatile organic compounds. These are compounds which easily become a vapor or gas. VOCs exhaust when burning fuels as well as off-gas from products like adhesives, paint, new carpet and mattresses. Coils also freeze due to low refrigerant levels or an issue with the fan. The coil will not cool the air if frozen.

Dirty Filter

Warm air may be due to a dirty air filter. Dirt and debris could be blocking airflow and hindering your AC’s performance.

Lack of Maintenance

AC maintenance is crucial for the health and longevity of your system. Schedule a maintenance every six months to ensure your system is working properly. One combined maintenance is included in our Silver or Gold Service Plans. Technicians often spot small, fixable problems before they become large, costly and more inconvenient. This ultimately saves you time and money in the long run.


Has your air conditioner reached the end of its useful life? Air conditioners can last an average of 15 years with average use and regular preventive maintenance. If you're unsure of your AC unit's age or have recently moved into your home, schedule an inspection or a full tune up. Your HVAC technician is happy to share the age, the estimated energy efficiency and other details about your AC system with you.

If it has required multiple repairs within a short period of time and is inefficient, consider a new AC installation. Between finance options and energy-efficiency gains, you enjoy lower electric bills, a new AC warranty and greater comfort and safety.

AC Not Cooling Problems: DIY

Check the Thermostat

Firstly, check to see if your thermostat is set to "heat" or "auto." At the beginning of a new season, it’s easy to forget to change settings. Additionally, if your thermostat isn’t turning on, it may need new batteries. These quick fixes are very common issues and could save you the time and expense of a service call.

A "smart" thermostat could significantly help and even save you extra money. Many alert you when the AC needs a filter change or to unusual performance, in an effort to prevent major AC repairs. If you have a manual or even a basic programmable thermostat, we are happy to recommend an upgrade.

Newer, modern Wi-Fi thermostats and "smart" thermostats communicate more effectively with your HVAC system for more accurate readings and air conditioner performance. With a Wi-Fi thermostat, adjust the temperature from anywhere you can get online - including the airport or the comfort of your bed.

Be sure to ask an A.B. May consultant for a recommendation. Some thermostats work with single-speed or variable-speed systems better than others. Make sure you're getting the most from your investment with advice from A.B. May!

Change The Filter

Next, go look at your air filter. Dirt and debris blocking airflow and hinder your AC’s performance. If it looks dirty, go ahead and replace it. Afterward, check the temperature of your home to see if it helped.

Clean Outdoor Unit of Debris

If you've neglected the outdoor unit, your system can't cool properly. Be sure to clean the unit of any debris and gently hose off all remaining dirt and mud. If you think rodents or other foreign objects are in or stuck in your AC compressor, call A.B. May. Also, give our team a call if you suspect a bent fan blade. It's safer to let us handle it.

Flip The Breaker

Have you checked the breaker? Turn the electrical breaker on and off. Sometimes, it's an easy fix. If after these steps you still find the air conditioner not cooling, call a professional HVAC contractor like A.B. May.

Call AB May if your AC is not cooling

Air Conditioner NOT Cooling: Call a Pro

The majority of AC mechanical issues should be fixed by a professional technician. As a result, if you notice issues with coolant, coil, compressor, or any leaks, call a certified A.B. May technician. He or she is the best person for the job.

Contact A.B. May in Kansas City for Air Conditioning Repair

Our team is available for 24-hour emergency service if necessary. We travel throughout the Kansas City area including Leawood, Olathe, Fairway, Parkville, Liberty, Brookside, Waldo, Lee's Summit and Prairie Village. We also serve customers in Overland Park, Stillwell, Lenexa, Merriam, Shawnee Mission, Blue Springs, Lake Quivira, Roeland Park, Independence, Plaza and Westwood.

Read More: Why is My AC Not Working?