Why Are My Lights Flickering When My AC Turns On?

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If you’ve noticed that your lights flicker or dim when you turn on your air conditioning unit, you are not alone. This phenomenon is quite common and can be caused by a variety of reasons. This guide will explore some of the most common causes of flickering lights when your air conditioner turns on, including electrical issues, wiring problems, and outdated equipment. We will also provide you with some tips on how to handle and fix the problem, as well as advice on when it is best to call in a professional. Keep reading to explore more about the lights flickering when AC turns on.

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

It is pretty common for lights to flicker when the air conditioning turns on. This happens because the AC requires a lot of electricity to start up. The sudden surge in power consumption can cause a momentary drop in voltage, which can cause the lights to flicker.

When the AC compressor turns on, it requires a large amount of power to start up and begin cooling the air. This sudden draw of electricity can cause a temporary voltage drop in your home’s electrical system, which can affect other appliances connected to the same circuit, including lights. As the AC stabilizes, the voltage should return to normal, and the lights should stop flickering.

If the flickering is persistent or severe, it could be an indication of a more significant problem, such as an overloaded circuit or faulty wiring. In such cases, it is best to consult a qualified electrician to assess the situation and make any necessary repairs or upgrades to the electrical system.

Unless you have a geothermal unit, the following can be anticipated:

  • Brief flickering or dimming of lights
  • Dimming of lights ranging from 3-5%, or potentially more

Standard outdoor air conditioning units draw a larger electrical load compared to geothermal air conditioners. Geothermal units derive their energy from deep within the earth, and the AC control unit is typically located next to the furnace. If the geothermal unit is placing a significant burden on your electrical system, it requires the expertise of a specialist.

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Indication of A Bigger Cooling System Problem

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Flickering lights when the AC turns on can indicate a bigger problem with the electrical system. Some possible causes of persistent or severe flickering include:

  • Overloaded circuit: If the circuit that the AC and lights are on is overloaded, it can cause the lights to flicker when the AC turns on. This can be a safety hazard and damage the electrical system over time.
  • Faulty wiring: Faulty wiring can cause voltage drops and other electrical problems. If the flickering is persistent, it may indicate faulty wiring that needs to be repaired or replaced.
  • Low voltage: If the voltage supplied to your home is low, it can cause flickering lights when the AC turns on. This may be caused by problems with the power grid or the transformer supplying power to your home.
  • The AC capacitor may be damaged or weakened: Just like a weak or broken car battery, a weak or broken AC capacitor can cause a significant drop in electrical power, drastically reducing light output. Usually, the lights will dim by around 30 to 50 percent. If you observe this issue, it is advisable to seek the assistance of a professional to evaluate the AC capacitor.
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How to Stop Lights from Flickering When You Turn On Your Air Conditioner

There are measures you can take to stop lights from flickering when you turn on your air conditioner:

  • Check the electrical system: Have a qualified electrician inspect the electrical system in your home. They will check for overloaded circuits, faulty wiring, or other problems that could be causing the voltage drop that results in the flickering lights.
  • Upgrade the electrical system: If your electrical system is outdated or insufficient for your needs, you may need to upgrade it to handle the load of your air conditioner and other appliances. This could involve replacing the electrical panel, upgrading the wiring, or installing additional circuits.
  • Use a hard start kit: Installing a hard start kit can help reduce the strain on your air conditioner’s compressor when it starts up, which can reduce the voltage drop and prevent the lights from flickering. This is a relatively inexpensive and straightforward solution that can be installed by a professional.
  • Use a dedicated circuit: If your air conditioner and lights are on the same circuit, consider having a dedicated circuit installed for your air conditioner. This will ensure the air conditioner has the power it needs without affecting other appliances on the same circuit.
  • Install voltage stabilizers: A voltage stabilizer can help regulate the voltage in your home, preventing fluctuations that could cause flickering lights. This is a more expensive solution but can provide long-term benefits and protect your electrical system from damage.
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Related Article: 10 Reasons Why Your AC Unit Isn’t Blowing Cool Air

Do Not DIY Electrical Air Conditioner Issues

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It is important not to DIY any electrical issues related to AC or lights for safety reasons. Electricity can be extremely dangerous and cause severe injury or even death if not handled properly. AC and lighting systems operate at high voltages and can pose a significant risk to individuals who are not trained in electrical work.

In addition to the risk of physical harm, attempting to fix electrical issues without the proper training and knowledge can lead to further damage to the system and potentially costly repairs. Electrical systems are complex, and even seemingly simple issues can have underlying causes that require a trained professional to diagnose and repair.

Always hire a licensed and qualified electrician to handle any electrical issues. They have the necessary knowledge, training, and equipment to perform the work safely and effectively, ensuring that your home or business remains safe and functional.

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Paying attention to lights flickering when the AC turns on is essential for safety, comfort, and peace of mind. These flickers could be a sign of electrical issues that need immediate attention from qualified technicians or electricians. Ignoring these signs may result in more significant electrical problems. It is important to be proactive and vigilant in identifying and addressing these issues promptly. By doing so, you can guarantee that your home is safe and comfortable, and you can enjoy peace of mind knowing that your electrical system is functioning correctly.

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