Yes. A power surge can damage the electrical parts of an air conditioner, and the damage does not always show up right away. The Electrical Safety Foundation International (ESFI) lists heating and air conditioning systems among the home equipment that surges can damage or wear out early. If your AC stopped working after a storm or an outage, a surge is one possible cause. Other faults can look the same, though, and only testing the system shows what actually failed.
Where surges come from
ESFI describes a power surge as a brief overvoltage event. Lightning, damaged power lines and utility grid switching are the outside sources. ESFI estimates that 80% of surges start inside the home, from large appliances turning on and off, faulty wiring or loose connections, overloaded or shorted circuits, and power coming back after an outage.
That last source is why an AC problem can show up right after the lights come back on, even if there was no lightning nearby.
What a surge can do to an AC
An air conditioner depends on a control board and several motors. ESFI lists circuit board failure and motor failure among the symptoms of power surges, and notes that surges can shorten the life of equipment as well as damage it outright. So a part can fail during the surge, or keep working for a while and fail later.
Signs to watch for after a surge or outage
- The thermostat calls for cooling, but the system does not start.
- The indoor fan runs while the outdoor unit stays off.
- The AC breaker trips again after it has been reset.
- The system starts and stops on its own.
- A burning smell, buzzing or another new noise.
None of these proves a surge caused the problem. Worn parts, wiring faults and thermostat problems can produce the same symptoms, so treat the list as a reason to have the system checked, not as a diagnosis.
What to do first
- If you see smoke or flames, get everyone out of the house and call 911.
- If you smell burning, turn the system off at the thermostat and leave it off. ESFI treats a burning smell as a possible sign of a serious wiring problem.
- Breakers are designed to be reset after a trip, but if the AC breaker trips again, leave it off. ESFI says frequent breaker trips point to a problem that a qualified electrician should inspect.
- During an outage, set the thermostat to off until power is back and steady. Ready.gov advises turning off or disconnecting appliances during an outage because power can return with surges.
- Write down when the problem started and what happened just before it, such as a storm, an outage or flickering lights. That helps whoever checks the system.
Does a surge protector help?
It can lower the risk, and it is the only device designed for the job. ESFI states that only surge protective devices protect against power surges; breakers, GFCIs and typical power strips do not.
For homes, ESFI describes permanently connected devices installed at or near the breaker box (Type 1 and Type 2) and point-of-use devices (Type 3), and recommends using them together for the best protection. It also notes that the 2020 National Electrical Code requires Type 1 or Type 2 protection in new and renovated homes. A whole-home device is wired into the electrical system, so have a qualified electrician advise on it and install it.
A surge protector reduces the chance of future damage. It does not repair a part that was already hit.
Getting the AC checked in Arlington
If your AC is not running normally after a surge, an outage or a storm, the next step is testing, not guessing at parts. ENERGY STAR’s maintenance checklist describes what a typical check-up covers, including tightening electrical connections, measuring voltage and current on motors, and checking the system’s controls and starting cycle. That kind of testing is how a technician tells surge damage apart from other faults.
Air Clinic handles AC repair in Arlington. To set up a visit, call (817) 226-2665 or use the contact page.