Nothing ruins a perfect summer day like a broken air conditioner. When you go inside expecting a blast of cold air, you are instead met with stale, lukewarm air.
When your air conditioning system breaks down, your home quickly becomes unbearable and you may want to move out. At least you can feel the fresh air and breeze outside.
Fortunately, a lack of cold air doesn’t necessarily mean you need a new HVAC system. But that certainly means you need a professional HVAC company to come to your home as soon as possible.
USA TODAY breaks down common reasons why your air conditioner might turn on when it won’t cool. Learn easy air conditioner troubleshooting tips, DIY fixes, and how to know when it’s time to call a professional.
Reasons why the air conditioner does not cool and what to do about it
Hot air coming from your air conditioner is a surprisingly common problem for homeowners. Often the system is still running, pumping air through the vents, but the temperature never drops.
If your central air isn’t cooling your home properly, the cause usually falls into one of two categories:
- Easy airflow restrictions that you can fix yourself
- Mechanical failure requiring professional repair
Before you call to schedule an appointment, you may be able to diagnose the problem yourself by running through a basic checklist. Additionally, understanding how the unit works makes it easier to pinpoint the exact fault.
How does an air conditioner work?
Air conditioners don’t actually produce cold air. It works by removing heat and moisture from indoor spaces and venting it outdoors. However, achieving that relocation requires the process to work in a continuous loop.
- An indoor fan pushes warm air into a cold evaporator coil.
- A chemical refrigerant inside the coil absorbs heat from the indoor air.
- The cooled air is forced back into the home through the ducts.
- The refrigerant moves to an outdoor condenser unit where a compressor releases the trapped heat to the outside.
“The importance of maintenance may vary a little depending on where you are in the U.S., but semi-annual maintenance is the basics,” says Joey Dooley, general manager of ARS, Texas, with more than 20 years of experience in the HVAC industry. “Nearly all manufacturers recommend it, but many also require substantial maintenance to protect their warranties.”
While it’s important to protect your HVAC warranty, regular maintenance also protects your wallet. The U.S. Department of Energy asserts that regular HVAC maintenance is essential to keep the heat exchange process operating efficiently. If any part of this cycle is interrupted, the system will struggle to cool down and may require repair.
The most common reasons why your air conditioner won’t cool down
Some of the most common reasons why your air conditioner won’t cool can be fixed without professional help. These include:
- Clogged air filter: Dirty filters restrict airflow and prevent warm air from passing through the cooling coils. If you don’t replace your filters when needed, your AC system can become less efficient. “[Modern]systems help us understand what is really going on and diagnose problems before panic or major failures occur,” Dooley says. This problem is often avoidable.
- Thermostat settings are incorrect: In some cases, the fix can be surprisingly easy. Check your thermostat to see if it’s accidentally set to “Heat” or if the fan is set to “On” instead of “Auto.” Setting your thermostat to “auto” is a good way to save energy and ensure your air conditioner responds accurately to indoor temperature.
- Dirty outdoor condenser unit: The outdoor unit requires space for heat to escape. Choking with tall grass, leaves, dirt, etc. traps heat in the system. Clear the area to ensure at least 2 feet of clear space on all sides.
- Low or leaking refrigerant: Refrigerants are the lifeblood of the cooling process. If your system has a small leak, it won’t have enough chemical power to absorb the heat in your room. This usually causes lukewarm air to be blown out of the system.
AC Troubleshooting Quick Checklist
Before you spend money on a service call, take these simple steps to eliminate minor issues.
- Check your thermostat. Make sure it is set to “Cool” and the temperature is lower than the current room temperature. In some cases, smart home technology can even diagnose the problem and report it to your home’s thermostat hub.
- Check the air filter. If the filter looks gray or is clogged with dust, replace it.
- Look at the outdoor unit. Remove any debris, branches, or weeds blocking the metal fins.
- Check the circuit breaker. Make sure that the breakers for the indoor fan and outdoor unit are turned on.
When to contact an HVAC professional to repair your air conditioner.
Homeowners can perform filters and basic cleaning, but certain tasks are dangerous or require special tools.
For example, Dooley points out that one of the most common problems that HVAC technicians discover early on is a bad capacitor. “Depending on where you live in the country, most people will have their system fail at least once within the first year or two. Capacitors don’t last as long as they used to.”
Diagnosing capacitor problems at home is difficult. So, after going through the troubleshooting checklist, contact a certified technician. Contact a technician immediately if you notice any of the following:
- There is a hissing or bubbling sound coming from the refrigerant line.
- Ice forms on copper wires or indoor evaporator coils.
- My outdoor compressor keeps clicking but won’t turn on.
- There is a burning electrical odor or smoke coming from any part of the system.
Handling chemical refrigerants can be dangerous, and EPA certification is often required to purchase chemical refrigerants. Leave your AC refrigerant-related problems to our HVAC experts. Don’t risk solving the problem with a DIY solution.
How much does it cost to repair an air conditioner?
Air conditioner repair costs vary depending on the nature of the problem. Minor adjustments only incur a standard diagnostic fee, while replacing major parts requires a larger investment.
“Prices range from $8,000 to $35,000,” says Josh Condor, division operations manager for ARS Central Division, a national HVAC installer. “I know it’s good to have a solid answer, but there are so many variables and factors involved: the size of your ducts, the current condition of your home, etc…”
The cost of purchasing a new air conditioner depends on the size of your home, system efficiency, air conditioner brand, ductwork, and more.
How to prevent AC cooling problems
The best way to deal with your air conditioner not cooling is to prevent the problem from happening in the first place. Regular maintenance is important to keep your home comfortable.
These simple habits will help keep your air conditioner running smoothly.
- Change your filters regularly. Replace standard filters every 30 to 90 days.
- Schedule annual reconciliation: Have your system inspected by a technician each spring before the summer heat arrives.
- Keep the register organized. Make sure that furniture and curtains do not block the indoor air supply vents.
Investing a small amount of time into preventive maintenance can extend the life of your system and potentially reduce your monthly energy bills.
FAQ
Why is my AC running but not cooling?
This usually indicates an airflow restriction, such as a clogged filter, or a mechanical problem, such as a failed condenser or low refrigerant. If you can’t resolve the problem yourself by cleaning the filter or adjusting the thermostat, contact a certified technician for a more accurate diagnosis.
How do I reset my AC?
This may vary slightly depending on brand and model, but powering down the unit, waiting 60 seconds, and powering it back on may help. You can also turn off the AC circuit breaker on your electrical panel, wait one minute, and then turn it back on.
Why is my air conditioner suddenly blowing warm air?
If warm air suddenly blows out, the outdoor unit may be turned off or the compressor may be overheating. Check if the circuit breaker is tripped.
Can refrigerant deficiency be repaired naturally?
No, air conditioners operate in a closed loop, so they don’t consume refrigerant like gas in your car’s tank. If the refrigerant is low, there is a physical leak and you will need to have it professionally repaired.
