How to Protect Your HVAC System from Power Surges

Like other home electronics, your HVAC system relies on a precise and controlled flow of electricity to operate. Whenever the flow of electricity spikes—or surges—it can overwhelm the capacity of your HVAC equipment’s sensitive circuitry, risking damage or failure. A power surge during a storm or from utility grid problems can negatively impact your HVAC system. Learn how to avoid costly damage.

What Is a Power Surge?

A power surge is a sudden increase in voltage that exceeds the normal flow of electricity in an electrical system. Power surges can happen in less than a blink of an eye and often last just a few microseconds. Most power surges go completely unnoticed, with the affected electrical system absorbing the increased supply safely and the flow returning to normal.

What Causes Power Surges?

Power surges can originate from internal or external sources of electricity. The main characteristic of a power surge is an oversupply of electricity, which means the cause must either add voltage to the system or cause an imbalance in the flow of electricity.

Internal Power Surges

At home, air conditioning units and refrigerators are the most common causes of a power surge, although smaller appliances can certainly alter voltage distribution. These internal surges are typically associated with inductive loads or the start and stop of a motor connected to the circuit.

Because internal surges are primarily the result of a shift in load distribution, they rarely damage appliances or HVAC equipment. The spike in electricity from an internal power surge isn’t high enough to damage a device’s internal circuitry—most of the time.

External Power Surges

External power surges are more likely to cause more damage because they introduce considerably more electricity than the home or business’s electrical system is designed to absorb. Lightning strikes are the most common example of an external power surge, but malfunctioning electrical utilities can also cause spikes in electricity flow, especially after an outage.

How Common Are Power Surges?

Minor power surges can occur multiple times per day without any consequences. At some level, these surges occur whenever we plug or unplug devices from a wall outlet, or the air conditioning unit turns on.

The highest risk of a major surge occurs during lightning storms. A nearby strike can cause a power surge as electricity jumps from power lines, cable lines, and tree branches to your home’s electrical system.

Lightning damage caused over $1.2 billion in insurance claims in 2023, affecting 70,787 households. While not every claim is HVAC or surge-related, this figure provides a glimpse into just how expensive recovering from lightning damage can be.

Can a Power Surge Damage HVAC Equipment?

Absolutely. Like any electrical device, a sudden or unexpected increase in electricity can damage the internal circuitry of your heating and cooling system. Air conditioning systems tend to experience more damage than furnaces because they are more likely to be plugged in and running during spring, summer, and fall thunderstorms.

How to Protect Your HVAC from Power Surges

Unfortunately, preventing HVAC damage from power surges isn’t as easy as you think. The most accessible solution—the humble surge protector—isn’t designed to power most residential heating and cooling equipment. Plugging your AC into a surge protector power strip may cause either (or both!) devices to malfunction or catch fire.

The best option is to install a whole home surge protector, which can protect all of your appliances and devices against 60-80% of the most common surges experienced in residential settings.

It’s important to note that even the best surge protectors can’t guarantee complete protection from lightning strikes, but they go a long way toward mitigating the risk.

HVAC Lighting Damage: After the Storm

Severe lightning storms are the greatest risk to your home’s electrical system and HVAC. While there isn’t much anyone can do to prevent lightning damage to HVAC units, there are a few ways to lower the risk.

  • Turn off your AC during a thunderstorm. Turning off your AC and other electrical devices can lower the risk of damage. If possible, unplug your AC unit altogether.
  • Cover your outdoor unit. While this won’t protect against lightning, it can prevent light damage from debris like sticks and smaller wind-borne hazards. Just be sure to remove the cover before you restart your AC!
  • Call the professionals. After a storm, visually inspect your outdoor and indoor air conditioning equipment for signs of damage, including scorch marks, signs of melting plastic, or smoke stains. If you see any issues, contact your local One Hour Heating & Air Conditioning before turning your HVAC system back on.

Protect Your HVAC Against Storms, Surges, And More

There are plenty of variables in maintaining your HVAC system, and power surges are yet another consideration for proactive homeowners. Luckily, you don’t have to manage your heating and cooling alone! One Hour Heating & Air Conditioning’s friendly and professional technicians provide reliable maintenance and fast repairs to make home life more comfortable—and predictable. Find a location near you or call 800-893-3523 to request an appointment today!