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How To Stop Lights From Dimming When AC Comes On

How To Stop Lights From Dimming When AC Comes On

Having problems with your lighting when you turn on your air conditioning unit is annoying, yet it’s a common issue in many households. While there are many reasons as to why this is happening, it’s usually an easy fix.

Here’s how you can stop lights from dimming when the AC comes on:

  1. Check the capacitor.
  2. Check the wires.
  3. Check the circuits.
  4. Call a professional.

While there are several reasons why your lights are dimming when the AC comes on, without knowing how to repair or replace the possible issues, you won’t have much to do. The best thing to do is to call a professional to take a look. If you’d like a more thorough guide on how to identify critical problems and what you can do, continue reading.

1. Check the Capacitor

A damaged capacitor is the most likely reason why your lights are dimming when the AC comes on. A capacitor stores electrical energy, like a battery, and gives the compressor the power to start.

If the capacitor is weak or damaged, it can cause lights to dim significantly when the AC starts because the compressor doesn’t have enough power. Having a professional check your capacitor is the best option, as it might need to be replaced. 

Installing a hard start kit, such as the Tomoral SPP6 Hard Start Kit from, can help stop the lights from dimming. This hard start kit improves the compressor’s starting torque by 500%, therefore prolonging the compressor’s life span and decreasing the chances of dimming lights.

Note: This particular model shows to be for an RV but you can likely find one specific for your HVAC.

However, a hard start kit won’t do any good on a capacitor that needs to be replaced, so ensuring your capacitor is in good working order is essential.

2. Check the Wires

Another issue that could be causing the lights to dim is faulty wiring. Faulty wiring can cause more problems than just dimming lights, so getting this issue fixed quickly is essential. 

A damaged wire can result in a current loss in your lights. So, if you have a problem with your wires, you’ll most likely notice the lights both dimming and flickering when the AC comes on. You may also hear a buzzing sound, which is a sure sign of a wiring problem.

There could also be bite marks on the wiring that is causing dimming or flickering lights. Unfortunately, bitten wires aren’t uncommon, so it could be the root of the issue. 

Aside from causing issues with your wiring, bitten wires are also a sign that you have or have had a pest problem, which means you may also need to call pest control services.

You can physically check the wiring for any damage or frays. However, repairing the wires is best left to the professionals (source).

3. Check the Circuits

Having a problem with the circuits is a more severe issue that could be causing dimming lights. When it comes to air conditioning and dimming lights, the problem is usually an overloaded circuit.

Air conditioner units typically need their own circuit to function correctly. Therefore, if other appliances are in the same circuit, it can overload and cause issues. This is especially common in older homes, and it can cause many other dangerous problems in the house, such as electric shock or even fires.

Checking to see if the circuits are overloaded will be difficult if you don’t know what you’re looking for. The main sign of an overloaded circuit include:

Since an overloaded circuit can be dangerous, it’s best to contact a professional to come out and look at your circuits. If they need to be fixed or replaced, it will have to be done by someone that can do so safely (source).

4. Call a Professional

Lastly, you may need to call a professional to find out why your lights are dimming when the AC comes on. While you can do more minor things and check to get to the root of the issue or even prevent the problem from happening again, you may need to contact a professional to fix the current situation.

Who Do I Call If My Lights Dim When the AC Comes On?

You should call an electrician if your lights dim when the air conditioning comes on. Electricians will rule out more significant problems such as overloaded circuits or damaged wires with flickering or dimming lights. Additionally, they are also trained to address more serious issues safely.

Why Does My Lights Dim When AC Turns On?

Lights dimming when the AC turns on doesn’t always mean there’s a problem that needs to be fixed. Unless the power dims so significantly that you can’t live with it, a small amount of dimming is usually a normal occurrence.

Your lights dims when the air conditioning turns on because of the compressor. When the compressor kicks on to run the air conditioning, it needs significant power, which causes all of the power to be directed towards the compressor. It’s normal for lights to dim a small amount during this time.

Final Thoughts

Stopping your lights from dimming when the AC comes on usually takes some time. First, you must identify the issue, which could be anything from a damaged capacitor to faulty wires or even overloaded circuits. If you don’t know much about electrical circuits or wiring, there isn’t much you can do yourself.

Therefore, paying attention to the other warning signs, such as flickering lights or buzzing sounds, is essential to finding the cause of concern. Contacting an electrician to come to fix the issue is recommended.

Recommended Reading:

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