What to Know about Flickering Lights When the HVAC Is On

Your Heating, Ventilation, and Air Conditioning (HVAC) system is a vital part of your residential property, as it serves to regulate your home temperature and keep the whole household comfortable. While it keeps the space warm during winter, it makes your home cold during summer. 

As a homeowner, you may have been used to turning your HVAC system on and off whenever you use it throughout the year. However, there could be times when you notice the lights are flickering when your cooling or heating systems cycle on. As such, you may have wondered why it happens, and we are here to provide answers!

In this article, we will explore more about why lights tend to flicker when your HVAC system turns on and when they’re considered to be problematic.

The reason lights flicker

It is actually normal for the lights to flicker whenever certain home units or systems are turned on. These flickering lights don’t only apply to your HVAC system alone as they happen to your microwaves, hairdryers, hot plates, and other units as well. 

The truth is that any appliance with high electrical surges causes this usual phenomenon. First, imagine your home’s electrical system and the appliances connected to it. When a high-wattage appliance is powered on, there will be an interruption in the electricity flow, and this causes the lights to flicker.

Why an HVAC system has flickering lights

Same with other home appliances, your HVAC system is no exception when causing lights to flicker. In fact, it is particularly the most vulnerable to this phenomenon since it has one of the highest wattages at home. The lights flicker during the first cycle before the power gets distributed evenly. In most cases, these occurrences are common in HVAC systems installed in older homes or those houses without electrical upgrades for many years.

When flickering lights become a problem

Based on the explanation above, flickering lights are considered to be usual among many home appliances. This means that you need not worry about your HVAC system if you notice those flickering lights regularly, particularly when you turn on the unit. 

However, you may want to consider upgrading your home’s electrical system as these flickering lights might be an indication of an outdated system as well. With the advancement of today’s technology, you can install a highly efficient and safe electrical system that will accommodate all your home appliances and systems, such as your HVAC unit.

However, when do flickering lights caused by your HVAC system become a major problem? That is usually when the flickering lights become prolonged. In fact, the flicker should only be brief—as if blinking an eye. But when they continue to happen even after the HVAC system is running for a while, it might indicate various internal issues that require expert intervention. These professionals will get to the bottom of the problem and make the necessary fix as soon as possible to avoid any safety hazard at home.


At this point, you now know why flickering lights happen with your HVAC system and other home appliances. To that end, be sure to consider all the valuable information discussed above, especially when it comes to calling a professional electrician or an HVAC specialist. Ultimately, we hope this article has shed some light on flickering light occurrences in your system and how you can remedy repeating problems.

Are you experiencing flickering lights whenever you turn on your HVAC system? Let our HVAC contractor deal with it! We provide heating and air conditioning services in Edmonton, such as HVAC repair, replacement, and even installation. Get in touch with us today to get a free quote!

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