Why Are My Lights Flickering When My AC Turns On?

image of a kitchen lights depicting lights flickering when ac unit turns on

You aren’t the only one who notices your lights flickering or dimming when you switch on your air conditioner. This problem is a relatively common one and has several causes. This article explores several top reasons your lights flicker when your air conditioner turns on, such as outdated systems, electrical issues, and wiring problems. We also offer some tips on how you can handle and resolve the issue, including advice on when you should call for professional help. Keep reading to learn about the lights flickering when AC turns on.

Explore Our Air Conditioning Services Call To Schedule A Free, In-Home Estimate

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

It is a common occurrence for lights to flicker when switching on your air conditioner. This happens because the air conditioner needs a considerable amount of electricity during startup. This sudden surge in energy use can cause the voltage to drop momentarily, causing the lights to flicker.

Turning the air conditioner compressor on requires a tremendous amount of power. This sudden electrical draw can cause the voltage in your home’s electrical system to drop temporarily. This can impact other appliances connected to the same circuits, like the lights. The voltage should return to normal once the air conditioner stabilizes, and this should stop the lights from flickering.

If there is persistent or severe flickering, it may mean that there is a more severe issue, like faulty wiring or an overloaded circuit. You should contact a qualified electrician to assess the situation if this is the case. They can make the needed repairs or upgrades to your home’s electrical system.

The following can be expected unless you own a geothermal unit:

  • The lights flickering or dimming for a brief moment
  • The lights dimming from 3% to 5% or more

Traditional outdoor AC units have a larger electrical load than geothermal units. The latter get their energy from deep into the earth, and the air conditioning control unit is usually next to the furnace. An expert is needed if your geothermal unit is placing a large amount of burden on your electrical system.

Call Today: (610) 377-1098

Related Article: What To Check When Your Air Conditioner Won’t Turn On

Indication of A Bigger Air Conditioner Problem

image of air conditioner capacitor

When the lights flicker when you turn on your air conditioner, you may have a bigger electrical system problem on your hands. Some likely reasons for severe or persistent flickering are:

  • Overloaded circuit: The lights can flicker when the air conditioner turns on if the circuit the air conditioner and lights are connected to is overloaded. This can be a safety risk and even cause damage to your electrical system as time passes.
  • Faulty wiring: This can result in electrical problems like voltage drops. Persistent flickering may point to faulty wiring that needs repairing or replacing.
  • Low voltage: If your home has a low voltage supply, the lights can flicker when the air conditioner turns on. Problems with the transformer or power grip supplying power to your house can cause this. 
  • Damaged or weakened air conditioner capacitor: A broken or weak capacitor can cause the electrical power to drop, drastically lowering your light output. The lights will typically dim around 30 to 50%. Call for professional assistance if you notice this issue so they can evaluate the AC capacitor.
Learn More About Our HVAC System Services Call To Schedule A Free Estimate

Related Article: Signs Your Air Conditioner Needs A Replacement

How to Stop Lights from Flickering When You Turn On Your Air Conditioner

ohl air conditioner services

Here are some methods you can do to keep your lights from flickering when turning on your air conditioner:

  • Check the electrical system: Hire a certified electrician to check the electrical system in your home. They will inspect for damaged wiring, overloaded circuits, or other issues causing the voltage to drop and the lights to flicker. 
  • Upgrade the electrical system: If you have an outdated electrical system or it isn’t enough for your needs, you may require an upgrade to keep up with the load of your air conditioner and other appliances. This can mean that the electrical panel will be replaced, the wiring upgraded, or additional circuits installed.
  • Use a hard start kit: A hard start kit can help reduce the burden on your air conditioner compressor during startup. In turn, the voltage drop is reduced, and the lights will not flicker. This is a pretty cheap and straightforward solution that a professional can install.
  • Use a dedicated circuit: Consider installing a dedicated circuit for your air conditioner if your cooling system and lights share the same one. This way, the air conditioner gets all the power it requires without affecting other appliances linked to the same circuit.
  • Install voltage stabilizers: A voltage stabilizer assists in regulating your home’s voltage. This prevents fluctuations causing the lights to flicker. This may be a more expensive solution, but it provides long-term advantages and protects your electrical system from damage.
Call To Schedule An Appointment

Related Article: Air Conditioner Noises To Be Aware Of

Do Not Conduct DIY On Electrical Air Conditioner Issues

image of a homeowner dealing with electric shock from DIY air conditioner repair

You should never DIY electrical issues linked to your air conditioner or lights for your safety. Electricity can be hazardous, cause severe injury, or even be fatal if mishandled. Air conditioners and lights use up high voltages and can pose significant risks to people without training in electrical work.

Besides the risk of physical harm, fixing electrical problems without the proper training and knowledge can result in more damage to the system that may need expensive repairs. Electrical systems are complex equipment, and seemingly simple problems can be due to underlying causes that need a trained professional to diagnose and resolve.

Leave any electrical issues in the hands of a licensed and qualified electrician. They have the right tools, extensive training, and knowledge to conduct the work safely and effectively. This way, you will surely have a safe and functional home or business.

Click To Schedule An Appointment Now! Read Our Reviews

Related Article: How Much Clearance Is Necessary Around an Outdoor AC Unit?


Do not ignore flickering lights when the air conditioner turns on because it is essential for your comfort, peace of mind, and safety. Flickers can point to electrical issues that must be resolved immediately by qualified technicians or electricians. Ignoring these signs may cause more severe electrical problems. Ensure you are proactive and vigilant in determining and resolving these issues promptly. This way, you are guaranteed a safe and comfortable home and the peace of mind of knowing you have a properly functioning electrical system.

Get Started - Call R.F. Ohl Todayt

Related Article: Air Balancing – 5 Easy Ways To Avoid Hot And Cold Spots In Your House

Call R.F. Ohl For All Your HVAC Requirements

RF Ohl logo

R.F. Ohl is the leading supplier of HVAC services throughout Northeastern Pennsylvania, including the Poconos and the Greater Lehigh Valley Region. Our highly skilled and certified technicians are experts in heating and cooling maintenance, repairs, replacements, and more. We are happy to deliver top-notch services to all our customers. 

At R.F. Ohl, we understand that having an energy-efficient and comfortable home is important. Hence, we offer affordable rates for our services. Our tune-up services are created to improve comfort and lower your energy costs. Our knowledgeable techs can help you find the best HVAC repair or replacement solutions within your budget. All our work has a satisfaction guarantee.

Book a service appointment with R.F. Ohl by calling us today. We provide free, in-home estimates so you can make informed decisions about your HVAC systems. Trust R.F. Ohl to provide superior heating and cooling services that exceed your expectations!

Call Now: (610) 377-1098 Explore Our Case Studies

Click here to contact us today or give us a call at (610) 377-1098 if you have any questions. Click the link to view our service area.