Every time your air conditioner kicks on, the lights in your home begin to flicker, giving off strong haunted house vibes. What’s going on?
Is there a problem with your AC unit? Is something up with your home’s electricity?
Maybe and maybe.
Join the team at AAA Heating and Cooling as they share the basics about how air conditioners work and reveal six reasons lights flicker when your home’s AC is running.
Table of Contents
- Understanding Your Residential Air Conditioning Unit
- 6 Reasons Lights Flash When the AC Turns on in Your Home
- AAA Heating and Cooling: Trusted HVAC Provider to Portland and the Surrounding Areas Since 1961
Understanding Your Residential Air Conditioning Unit
Think of electricity in your home the same way you do your residential plumbing.
Much like the water in your pipes, there is only so much electricity available in your home at any given time. When you flush your home toilet while the shower is running, the water pressure splits between the two fixtures.
Electricity behaves similarly.
When you turn on a high-energy device, like your air conditioner unit, the initial power draw can put a substantial drain on your available electricity, causing your lights to dim. While flickering lights might seem like a big deal, this is often a normal electrical response to power being diverted.
How can you tell if the house lights dimming when the AC turns on is normal or a sign of a larger problem?
For a normally functioning air conditioner, you’ll experience lights:
- Dimming for a split second
- Losing only about 5% of their brightness
You may have more serious electrical issues if your lights:
- Dim for a long amount time
- Rapidly flicker on and off
- Only dim on particular circuits
Not sure if your wires need repair? Make an appointment with the HVAC professionals at AAA Heating and Cooling to find out if your wires are discolored, charred, or loose.
6 Reasons Lights Flash When the AC Turns on in Your Home
#1. Damaged or Loose Wires
If your lights flash when the AC turns on, it could be indicative of loose or damaged electrical wires. Faulty wires may decrease the flow of electrical current to your lightbulbs. The voltage drop that occurs when your air conditioner kicks on can also exacerbate the problem, making your lights flicker rapidly.
#2. Weak or Broken Capacitor
If your lights are losing 30% to 40% percent of their illumination when the AC starts, that’s a sign of a capacitor issue.
Your AC capacitor functions like a battery, giving your compression motor the boost of energy it needs to power up. Much like your car battery, your air conditioning compressor can lose its ability to store and maintain power.
What does this mean? Your AC is pulling more voltage from other appliances and putting more stress on your compressor to start up. This can cause the house lights to dim when the AC turns on.
#3. Overloaded Circuits
Overloaded circuits can present a serious problem.
According to the National Electric Safety Code, all major appliances should be on their own dedicated circuit.
If you trip your circuit breaker or hear any buzzing sounds when you turn on your AC unit, you could be overloading your circuits.
Should you notice any of these signs, unplug any household devices that share the same circuit as your AC unit to reduce your risk of fires and electrical shock.
For a long-term solution, call AAA Heating and Cooling for a complete assessment.
#4: Aging Electrical System
If you live in a home that has an older electrical system, this could explain why your lights flash when the AC turns on. Older systems often lack the capacity to handle the increased electrical demand of our high-powered, modern appliances, including air conditioners.
Older or outdated electrical wiring may also degrade over time and lose its effectiveness at efficiently transmitting electricity. When this occurs and the air conditioner is turned on, the sudden surge in electrical demand puts stress on these aging components and causes the lights to flicker.
#5: Short Cycling
Short cycling occurs when your air conditioner turns off and on repeatedly over a short period. This continual turning off and on places significant strain on your home’s electrical system, causing your lights to flash when the AC turns on.
If your air conditioner is experiencing short-cycling, get it checked by a professional HVAC technician, like the team at AAA Heating and Cooling, to prevent damaging both your AC and your home’s electrical system.
#6: Undersized Electrical Service Panel
The electrical service panels of many older homes were designed to handle considerably lower energy demands than what’s required by today’s appliances.
When your electrical panel experiences overload, it may struggle to allocate enough power to sustain your home’s needs, resulting in lights flashing when the AC turns on.
If this is the cause, consider upgrading your electrical service panel to a modern capacity of at least 200 amps to avoid costly repairs and increased energy costs.
This electrical upgrade is a great step toward an energy-efficient home and ensures your home can safely and efficiently handle the electrical requirements of your appliances and devices.
AAA Heating and Cooling: Trusted HVAC Provider to Portland and the Surrounding Areas Since 1961
If you aren’t sure why your house lights flicker when your AC turns on, it’s time to call in the experts.
AAA Heating and Cooling is your go-to residential and commercial HVAC servicing and installation company.
With locations in Portland and Beaverton, our family-owned business has dedicated over 60 years to meeting local HVAC needs by providing the highest quality services, repairs, installations, and customer care.
Whether your lights flicker when your AC turns on or your air conditioner isn’t towing the line when it comes to keeping your home cool and comfortable, the team at AAA can ensure your Portland residential air conditioner is running properly and ready to beat the heat.