Jul 17

Why Are My Lights Flickering When My AC Turns On?

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Experiencing flickering or dimming lights when you turn on your air conditioning unit is a common occurrence that many people encounter. There are many potential causes for this issue, including electrical problems, wiring issues, and outdated equipment. In this guide, we will tackle common causes and provide helpful tips on addressing and resolving the problem, lights flickering when AC turns on.

We understand that dealing with flickering lights can be frustrating, so we will offer practical advice on troubleshooting and fixing the issue. However, it is best to seek professional assistance to ensure a safe and effective resolution.

Continue reading to understand why your lights flicker when your AC turns on, and learn effective strategies for addressing this common problem.

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Is It Normal for Lights to Flicker When the Air Conditioner Turns On?

When the air conditioning turns on, it is common for lights to flicker due to the high electricity demand during startup. The sudden power surge can cause a temporary voltage drop, resulting in flickering lights.

The AC compressor requires substantial power to initiate the cooling process. This rapid electricity consumption can lead to a momentary decrease in voltage, affecting other appliances on the same circuit, including lights. As the AC stabilizes, the voltage should normalize, and the flickering lights should cease.

However, persistent or severe flickering may indicate underlying issues like overloaded circuits or faulty wiring. In such cases, seek assistance from a qualified electrician to assess and address the problem.

Unless you have a geothermal unit, the following scenarios are typical:

  • Brief flickering or dimming of lights
  • Lights dimming around 3-5% or potentially more

Conventional outdoor air conditioning units draw more electrical load than geothermal units, which derive energy from the earth. If your geothermal unit is putting excessive strain on the electrical system, it requires the expertise of a specialist to address the issue.

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Related Article: 10 Reasons Why Your AC Unit Isn’t Blowing Cool Air

Indication of A Bigger Air Conditioner Problem

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Flickering lights when the AC turns on can indicate underlying electrical system issues. Some potential causes of persistent or severe flickering include:

  1. Overloaded circuit: If the circuit supporting both the AC and lights is overloaded, it can lead to flickering. This poses safety risks and can harm the electrical system in the long run.
  2. Faulty wiring: Faulty wiring can result in voltage drops and other electrical problems. If the flickering persists, it might indicate the need for wiring repairs or replacements.
  3. Low voltage: Insufficient voltage supplied to your home can cause flickering when the AC kicks in. This could stem from power grid issues or problems with the transformer delivering power.
  4. Damaged or weakened AC capacitor: Similar to a weak or faulty car battery, a damaged or weakened AC capacitor can cause a significant drop in electrical power, resulting in noticeable light dimming of approximately 30 to 50 percent. If you notice this issue, consult a professional to assess the AC capacitor.
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Related Article: Tell-Tale Signs of An Overcharged Air Conditioner

How to Stop Lights from Flickering When You Turn On Your AC

To prevent lights from flickering when you turn on your air conditioner, you can take the following measures:

  • Check the electrical system: Engage a qualified electrician to inspect your home’s electrical system. They will examine for overloaded circuits, faulty wiring, or other issues leading to voltage drops and flickering lights.
  • Upgrade the electrical system: If it is outdated or insufficient for your needs, consider upgrading it to handle the load of your air conditioner and other appliances. This may involve replacing the electrical panel, upgrading wiring, or adding extra circuits.
  • Use a hard start kit: Installing a hard start kit can alleviate the strain on your air conditioner’s compressor during startup, reducing voltage drops and preventing lights from flickering. A professional can easily install this cost-effective solution.
  • Use a dedicated circuit: If your air conditioner and lights share the same circuit, consider installing a dedicated circuit exclusively for your air conditioner. This ensures the air conditioner receives sufficient power without affecting other appliances on the same circuit.
  • Install voltage stabilizers: Voltage stabilizers can regulate the voltage in your home, preventing fluctuations that can cause lights to flicker. While this is a pricier solution, it offers long-term benefits and protects your electrical system from potential damage.
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Related Article: Smoke Coming From Vents When AC Is On

Do Not DIY Air Conditioner Electrical Issues

It is crucial to prioritize safety and avoid attempting any DIY electrical work concerning air conditioning or lighting systems. Dealing with electricity can be highly hazardous, with the potential for severe injuries or even fatal accidents if mishandled. AC and lighting systems operate at high voltages, posing significant risks to individuals without proper electrical training.

Beyond physical harm, attempting to fix electrical issues without the necessary expertise can result in further damage to the system, potentially leading to costly repairs. Electrical systems are intricate, and seemingly minor problems can have underlying causes that require the expertise of a trained professional to diagnose and resolve.

Always enlist the services of a licensed and qualified electrician to address any electrical issues. These professionals possess the requisite knowledge, training, and specialized tools to carry out the work safely and effectively, ensuring your home or business’s ongoing safety and functionality.

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Related Article: Why Is My Air Conditioner Running In Short Bursts?


Being mindful of lights flickering when the AC turns on is crucial for safety, comfort, and peace of mind. Flickering can indicate underlying electrical issues that require the expertise of qualified technicians or electricians. Neglecting these warning signs may lead to more significant electrical problems. Take a proactive and vigilant approach to identifying and resolving these issues promptly. Doing so ensures the safety and comfort of your home while enjoying the reassurance that your electrical system is functioning properly.

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Related Article: 5 Most Common Thermostat Problems Impacting Your Comfort

Call Skylands Energy Service For All Of Your HVAC Requirements

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Skylands Energy Service is the premier provider of heating and cooling solutions throughout central New Jersey. Our HVAC team consists of highly-trained, skilled, and certified technicians specializing in a wide range of HVAC services, including tune-ups, repairs, installations, replacements, and more. We take pride in providing exceptional HVAC services to our valued clients.

At Skylands Energy Service, we understand the importance of a comfortable and energy-efficient home. That’s why we offer competitive pricing for our services. Our maintenance programs are designed to optimize comfort while reducing energy costs. If you need HVAC repair or replacement, our knowledgeable technicians will recommend the best solution tailored to your budget. We stand behind our professional work and offer a satisfaction guarantee.

Scheduling a maintenance or service appointment with us is easy. Call us, and we’ll provide a free, in-home estimate to help you make informed decisions about your HVAC systems. Trust Skylands Energy Service to exceed your expectations with our outstanding heating and cooling services!

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