AC Not Working After Power Outage? 4 Reasons Why and What to Do
Keep your cool while you troubleshoot
Highlights
A tripped circuit breaker is a common culprit and requires a reset.
Because many AC systems have built-in surge protection, wait 30 minutes after resetting your circuit breaker to power on your AC again.
In some cases, certain parts of an AC unit, like a compressor or capacitor, can blow from a power surge.
Contact an HVAC pro after basic troubleshooting to fix any permanent issues.
Whether a power outage lasts seconds or hours, it can cause your air conditioner to stop working, but don't worry. It's likely only temporary. When you find your AC not working after a power outage, it’s often due to a tripped circuit breaker or the unit’s built-in surge protection. But in some cases, AC units can be damaged after a power outage. Check out these common reasons your AC is not working after a power outage and what to do in each situation.
1. Built-In Blackout and Brownout Protection
Some types of air conditioners have built-in protection against power surges and power outages. In most cases, there’s a 30-minute reset timeframe that prevents the condenser from power cycling, which can damage your AC unit. By waiting out the reset time, you allow your AC unit to work normally again.
How to identify and fix the problem:
Turn off the air conditioner from your thermostat.
Go to your electrical panel and locate the circuit breakers for your AC units. There are two: one for your outdoor unit and one for your indoor unit.
Flip the switches to the “off" position on the breaker panel and then switch them back to the "on" position.
Wait 30 minutes before starting your AC again. The 30-minute buffer gives the system time to reset fully.
Turn the AC back on from the thermostat.
Wait 10 minutes to see if the AC starts working again and is blowing cool air.
2. Tripped Breaker
The indoor and outdoor units of your cooling system are on individual circuit breakers. When a power surge happens, such as right before an outage, the breakers trip to cut power to the circuit. Sometimes, one breaker or both have tripped.
If the breaker to the outdoor unit trips but the indoor one doesn't, the indoor unit will blow air through the ducts, but it won’t be cool air. If both breakers trip, the AC won’t turn on at all.
How to identify and fix the problem:
Go to your electrical panel.
Identify the circuit breakers that power your cooling system components.
If the circuit breakers marked condenser, indoor AC, or outdoor AC are off, reset them by moving the breaker to the “on” position.
If the breaker trips again immediately, do not reset it. Hire an HVAC pro to fix the problem.
3. Failed Compressor
An AC compressor can fail after a power surge. When this happens, there is no heat exchange, and no cold air comes through. The compressor is not circulating refrigerant to extract the warm air.
How to identify and fix the problem:
If you have a failed compressor, you’re likely to experience airflow issues, warm air blowing through your ducts, and loud noises in your HVAC system.
Contact a local HVAC technician if you notice these symptoms. A trained professional should repair or replace an AC compressor.
4. Failed Capacitor
The AC capacitor starts up the unit's compressor. Power outage surges can cause the capacitor to blow. After power comes back, the capacitor won't work. This means that the outdoor unit won't perform a heat exchange even though the indoor unit is working. Again, the AC will blow air, but it won’t be cool air.
How to identify and fix the problem:
Go to your outdoor AC unit.
Check to see if the capacitor is blown. The capacitor looks like a canister on top of the compressor. If the capacitor blows, the top bulges or leaks oil.
Contact an HVAC technician. A trained professional should replace an AC capacitor.
When to Contact an HVAC Pro
If you’ve tried figuring out why your AC is not working after a power outage and you can’t determine the issue, contact a local HVAC repair technician who can diagnose and fix the issue. The cost of AC repair falls between $450 and $2,000, depending on what component breaks. An HVAC service call is $100 to $250. A trusted pro can help you get your house cool again in no time.
Frequently Asked Questions
You reset your AC after a power outage by turning off the air conditioner from the thermostat, resetting the circuit breaker, waiting 30 minutes, turning on the AC from the thermostat, and waiting 10 minutes to see the impact. Sometimes, with a power outage, the AC needs time to reset itself, so resetting the circuit breaker alone may not do the trick.
Your AC might not cool after a power outage because of a tripped circuit breaker, blown fuse, or damage to the compressor or capacitor. If you notice your AC not working after a power outage, in most cases, the breaker has tripped or the system has built-in brownout and blackout protection. Reboot the AC by turning it off at the thermostat, resetting the circuit breaker, and waiting 30 minutes to turn the AC on again.
A power outage can damage your air conditioner, just like a power surge can damage any electrical device or appliance. In most cases, your circuit breaker or built-in surge protection on your AC unit protects your AC and just needs a reset. But in other cases, it might be that your AC compressor or capacitor was blown during the power surge. You’ll need to have an HVAC professional repair or replace any AC parts.