Why Do Your Lights Flicker When Your AC Unit Turns On?

April 24, 2019

Murrieta homeowners may notice that the lights in their home flicker slightly whenever their HVAC turns on. This is because your AC requires a large amount of electricity to initially start up. When it starts, it temporarily drains power from other appliances like your lights, causing them to flicker slightly. This is usually a completely normal result of high demand on a limited power supply, especially in older homes that weren’t built to accommodate the power requirements of a modern AC unit. If your lights only dim for less than a second, and they lose about 5 percent of their brightness, then the likelihood is that you have nothing to worry about. However, if your lights constantly flicker, brighten before flickering, or dim significantly, it could also be a sign of a more significant electrical problem.

Damaged or loose wires

If you notice that your lights turn on and off rapidly and repeatedly when your AC turns on, then it’s possible that you may have damaged or loose wires. This damage, such as discolored or charred wiring, is likely causing current loss to your lightbulb. In combination with the temporary voltage drop that occurs when your AC turns on, it could cause your lights to dim or flicker more significantly than is normal. If you suspect that your wiring may be damaged, call a professional AC repair service right away to have them inspect the problem.

Damaged or weak capacitor

It’s normal for your lights to dim 3-5 percent when your AC unit starts. However, if your lights lose almost half of their brightness when the HVAC turns on, you likely have a damaged or weak capacitor. Your capacitor gives your compressor motor the extra power it needs to start. Over time, capacitors can lose their ability to store energy, and when this happens your AC requires more voltage from other appliances to start up. This causes your light bulbs to dim much more than usual. If you notice your lights dimming much more significantly than you feel is normal, call an AC repair professional to assess your capacitor and have it replaced.

Overloaded circuit

If you hear a crackling or sizzling sound accompanying the dimming of your lights, or if the lights go out completely when your AC turns on, you may have an overloaded circuit. Your air conditioner requires its own dedicated circuit to function correctly and safely. If there are other appliances on the same circuit as your air conditioning, they could be overloading the circuit. This is especially common in older houses that were not originally designed for modern air conditioners. An overloaded circuit is dangerous, as it could cause fires and electric shock. If you suspect that your circuit may be overloaded, immediately unplug any appliances that are on the same circuit as your AC. Afterwards, call an AC repair professional right away to inspect your home’s electrical system and find an alternate solution that will prevent an overloaded circuit.

Most of the time, flickering lights in your home are nothing to worry about. They’re a normal consequence of an AC unit’s initial energy pull, and they don’t pose any danger to you or your home. However, if you’ve noticed any of the symptoms above or if you’re still worried about what’s causing the lights to flicker in your Murrieta home, call the experts at ProFlo today at (951) 694-1300. We’ll investigate the problem and provide high-quality AC repair service right away.

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