Why You Need to Prevent HVAC Coil Corrosion

Depending on your HVAC unit, its lifespan could be up to 25 years. However, coil corrosion can negatively impact the longevity of your HVAC system. If you’re not actively preventing coil corrosion, you may be caught unawares by a ruined condenser or evaporator coil and end up facing an expensive, premature HVAC replacement. It’s better for both your HVAC system and your wallet to prevent coil corrosion in the first place.

What Are the Coils in an HVAC System?

Within your HVAC system, the coils are one of the most important components. This is because it’s in the coils that heat is exchanged. There are two coils in an HVAC system: a condenser coil and an evaporator coil.

What Is a Condenser Coil?

An HVAC condenser coil is located within the outdoor HVAC unit and is responsible for regulating the refrigerant’s temperature. It’s the condenser coil that takes hot air and releases it out of the HVAC system into the outside.

What Is an Evaporator Coil?

The evaporator coil is an HVAC component that resides within the house. It’s what pulls heat from the air inside and sends that hot air to the HVAC unit to be absorbed into the refrigerant that’s in the condenser coil.

What Causes Coil Corrosion?

Coil corrosion occurs in one of two ways:

• The outdoor condenser coil becomes pitted from exposure to corrosive substances in the air and rain, such as fluoride and chloride.
• The indoor evaporator coil corrodes due to airborne volatile organic compounds (VOCs) that are off-gassed by building materials, pressed-wood furniture components, as well as textiles, fabrics, and various everyday household products. Once these compounds settle on the coil surface, they turn into caustic formic and acetic acids.

How Does Coil Corrosion Impact the HVAC Unit?

No matter what causes the corrosion in the first place, corrosion causes holes to form in the coil. Refrigerants can then leak out through these holes. This in turn can cause:

• Higher energy bills
• Decreased efficiency
• Decline in comfort
• Shortened lifespan

How Does Coil Corrosion Cost Money?

Coil corrosion reduces the efficiency of the HVAC unit, which means that the unit has to work harder to produce subpar results. This costs money in the form of increased energy bills. Plus, you’ll also have to spend money on a new HVAC unit sooner rather than later.

What Are the Signs of Coil Corrosion?

Coil corrosion may be difficult to see because the coils are located within the HVAC system. However, corrosion does cause coil leaks, which have the following signs:

• Higher energy bills
• Hissing sounds
• Frozen coils
• Water leaks
• Longer cooling cycles
• HVAC unit not producing cold air
• Bubbles within the evaporator coil

How to Prevent Coil Corrosion

Regular professional HVAC maintenance that includes cleaning the coils is the best way to keep corrosion under control. An experienced HVAC pro knows the right methods and products to use to safely neutralize and remove caustic accumulations from the coils. A pro may also recommend:

• Have an anti-corrosive coating applied on the coils once they’re clean.
• Install a whole-house air cleaner on your HVAC system to capture and eliminate airborne VOCs.
• Rinse down your outdoor unit with the hose every month to limit the buildup of potentially-harmful debris.