The Lights Flash When I Use My HVAC. Should I Be Nervous?

Most things in your home run on electricity—from charging your cell phone to keeping the temperature inside where you want it. That’s why it’s infuriating when electricity in our homes doesn’t work the way we expect. For many homeowners, this stress can come to a head when lights flicker after their air conditioning or heating system starts to kick in.

The question remains: Do dimming or flickering lights at the beginning of HVAC cycles show a serious electrical problem? It varies.

When are dimming or flickering lights considered usual?

If you’re seeing dimming that lasts for a fraction of a second when your HVAC kicks in, it usually isn’t something to be stressed about.

While it might not feel like it, your home has a regulated amount of electricity it can use at any given time. Large appliances—like your HVAC system—need a significant amount of electricity to start up. When those appliances turn on, they take a larger amount of the available electricity. This means the other appliances in your home, like your lights, don’t have as much power available to them.

If this is the lone issue you are facing, your lights should dim for less than a second and quickly return to full brightness. If you’re done with the flickering, schedule an appointment with Precision Mechanical. We’ll assess the situation and see if an equipment upgrade or circuit changes can alleviate the problem.

When should I worry about flickering lights?

Flickering lights can also indicate a more serious matter. Don’t investigate yourself. The problem could be unsafe for you or your home. Contact a professional if you see:

• Lights that continue to flicker. The normal flickering that occurs when there isn’t enough power to support all appliances in your home should last a fraction of a second. If your lights continue to flicker on and off when you start your HVAC system—or consistently at any other time—you could have an issue with your wiring.
• Lights that dim significantly. When you experience usual dimming, the effect is enough that you notice a small, brief change. If the intensity of your lights abruptly drops considerably, you could have something wrong with the outdoor compressor on your air conditioner.
• A circuit breaker trip when you switch on your HVAC. Circuit breakers are a critical part of your home’s electrical system. When they trip and shut off power to a part of your house (powered by a specific circuit), they are attempting to protect you from an issue with your circuit. While it might be that you have too many appliances on the same circuit, it’s smart to bring a professional in to confirm there isn’t a more serious problem.

Any time your HVAC system and lights don’t work together, it’s safe to call a technician in to take a look. The team at Precision Mechanical is here to help. When you need us, you can give us a call at 605-206-3766 or make an appointment online. We’ll make sure everything is in order so you can feel safe in your home.