While it won’t fix some mechanical problems, a quick AC reset is the first step in troubleshooting common AC issues. Whether your air conditioner stopped running or is experiencing recurring issues, here’s how to troubleshoot air conditioner problems with a good old-fashioned reset. 

First, Here’s When to Reset an AC Unit 

We recommend manually resetting your AC system as a preliminary troubleshooting step, especially if you’re experiencing AC issues like:

  • AC blowing warm air
  • Inconsistent temperatures
  • Short cycling

If a reset doesn’t work or you're experiencing foul smells, strange sounds, or increased energy bills, it’s time to call the professionals for an in-depth inspection and reliable repairs.

Why Do I Need to Reset My Air Conditioner?

The most common reason to reset an AC unit is when the protection circuit breaker in your AC unit kicks in. In most cases, the protection circuit breaker is triggered during a power outage and is designed to prevent fires and explosions. 

In other situations, a manual reset can correct an AC that’s only blowing warm air, even when the thermostat is set to “cool.” While there are several possible reasons your AC could be blowing warm air, a quick AC reset readily addresses a general thermostat error. 

Related: Why Your AC Is Making Noise (& How to Fix It)

Getting Started: Where Is the AC Reset Button?

Resetting your AC unit might seem complicated, but even older models have a readily accessible reset button or a series of actions you can do to reset the system. While the following steps will work for most systems, you may need to find your owner’s manual or contact the manufacturer for model-specific instructions.

How to Reset Portable AC Units

In AC systems, the air conditioner reset button is on the outside unit’s lower edge, typically close to the ground. Some models have the reset button located behind the service panel, which may require tools to remove. Reset buttons are usually red or yellow with a clear “reset” label. 

How to Reset Portable Window AC Units?

On window air conditioners, the reset button is usually on the control panel or located where the power cord connects to the base of the unit. If your window AC unit doesn’t have a reset button, try unplugging it for a few seconds and then plug it back in. If you’re having trouble with your window unit, it may be a good time to invest in an air-source heat pump to provide cooling and heating for your home! 

How to Reset an Air Conditioner in Four Steps

  1. Power down your AC. Turn off the power at the circuit breaker. This prevents the unit from cycling before or during the reset and protects you from electric shock. Don’t worry, these units are designed to reset with the power off! 
  2. Press the reset button.  Most models require you to hold the button down for 3-5 seconds before releasing. 
  3. Restore power to your AC. Restore power to the unit at the circuit breaker, and make sure the unit is set to “on” and your thermostat is set to “cool.” 
  4. Listen and monitor. Listen for the unit to cycle on and make sure it's blowing cool air by placing your hand over an air vent. 

After a few seconds, your air conditioner should start up. You’ve successfully completed a reset! Next, go to your thermostat and make sure it’s set to a temperature that’s lower than the current temperature inside your home. 

If the AC reset button is not working, there may be underlying mechanical or electrical issues prohibiting a successful reset. Your local One Hour Heating & Air Conditioning® can find the root cause and recommend the repair you need to get your AC working again quickly! 

What Is an AC Compressor?

Some savvy homeowners may discover that they have an issue specifically with the AC compressor. The AC compressor is a vital part of your air conditioning system. It acts like the heart of your HVAC unit, circulating refrigerant through the system to help remove heat from your home. When your AC is on, the compressor works hard to compress and move refrigerant between the evaporator and condenser coils. If your compressor isn’t functioning properly, your system won’t be able to cool your home efficiently—if at all.

A failing compressor may show signs like loud noises, warm air blowing from vents, or the outdoor unit not turning on. Since the compressor is such a critical and complex component, it's important to leave most repairs to licensed HVAC professionals. Most homeowners can, however, attempt to reset the compressor by following steps similar to those previously outlined.

How to Reset an AC Compressor

  1. Turn off your AC system at the thermostat. This stops the system from calling for cooling while you reset the compressor.

  2. Shut off power at the breaker. Locate your electrical panel and turn off the breaker connected to your HVAC unit to fully power it down.

  3. Wait 30 seconds to 1 minute. Give the system a brief rest to allow internal pressure to equalize and the control board to reset.

  4. Restore power and restart your system. Turn the breaker back on, wait a few seconds, then turn your thermostat back on and set it to cool.

If the compressor doesn’t turn back on or your AC still isn’t cooling properly, it could be a sign of a deeper issue—such as a blown capacitor, refrigerant leak, or compressor failure. In that case, it’s time to call the professionals at One Hour Heating & Air Conditioning for a full inspection.

When the AC Reset Doesn’t Work, We’ll Get the Job Done

Every One Hour® technician is licensed, experienced, and equipped to handle any air conditioning problems. We provide prompt and professional cooling service and repairs to keep you and your family comfortable no matter how hot it gets outdoors. 

If an AC reset doesn’t fix the problem, we will. Find a location near you or call (800) 893-3523 to schedule service today.