Maintaining your HVAC system is critical for keeping your home or business comfortable. One hidden threat that often sneaks up on HVAC systems is corrosion. Left unchecked, corrosion can sabotage the efficiency of your cooling and heating systems, leading to costly repairs or replacements.
The good news? There are practical steps you can take to minimize and prevent corrosion before it wreaks havoc on your HVAC system. In this guide, we’ll break down exactly why corrosion happens and provide actionable tips to keep your system running smoothly.
What Causes HVAC Corrosion?
Metals corrode when they come into contact with acidic or basic (alkaline) substances. These substances interact with surfaces like your HVAC’s coils, causing damage over time. Corrosion is often linked to water. While water may seem harmless, it behaves as both an acid and a base, depending on its environment, and can interact with other molecules to form acids.
The result? Damage to your A/C’s coils, which are critical to moving refrigerant. If these corrode, they can leak refrigerant, leaving your HVAC system unable to effectively cool or heat your space.
Think of it this way: like how leaving a nail outside in the rain leads to rust, your HVAC system can experience similar damage if safeguards aren’t in place.
The Silent Saboteurs Acids in Your HVAC System
Acids don’t just magically appear; they’re formed by your very environment. Here are some common culprits behind acid-induced corrosion for HVAC systems:
- Carbonic acid: Forms when carbon dioxide interacts with water.
- Chlorides: Found in salts, building materials, and cleaning products.
- Acetic and formic acid: Result from off-gassing furniture, paint, and cleaning supplies.
- Nitric acid: Created by some combustion appliances, like furnaces.
Even weak acids can make a coil surface vulnerable to stronger acids over time, creating a dangerous snowball effect.
Prevention is Better Than Cure Stop Corrosion in Its Tracks
The key to keeping acids from damaging your HVAC system is to prevent their formation in the first place. How? By focusing on three critical aspects of indoor air quality:
1. High-Quality Filtration
Invest in filters with high surface area, like MERV 13 or higher media filters, which are excellent at trapping pollutants. These filters are capable of catching even volatile organic compounds (VOCs) that off-gas from furniture and paints.
For superior results, consider activated carbon filters. They don’t just catch pollutants but also “adsorb” VOCs, meaning the pollutants stick to the filter’s surface to prevent them from floating around.
2. Effective Ventilation
Good ventilation is critical for diluting harmful substances. Introducing fresh air through a controlled path, such as with a ventilating dehumidifier, reduces concentrations of carbon dioxide and nitric oxides that contribute to acid formation.
3. Humidity Control
Keeping your indoor humidity under control is more important than you might think. Aim for an indoor relative humidity below 60 percent to prevent dew formation, which can set off harmful chemical reactions.
Pro Tip: Dehumidifiers are your best ally here. They help keep moisture levels low and ensure water molecules don’t interact with VOCs or carbon dioxide, preventing acid formation.
Avoid DIY Corrosion Pitfalls
When it comes to cleaning your HVAC system, taking the wrong approach can make things worse. For example, never use bleach to unclog HVAC drains, as bleach is an alkaline substance that can corrode copper. Instead, use water and a shop vacuum to clean the drain.
Need something to prevent bacterial growth? Pour a cup of white vinegar down your drain monthly. It’s effective without the risky side effects of harsher cleaning solutions.
Recognizing the Signs of Corrosion
Not all corrosion is a cause for alarm, but understanding what you’re seeing is key.
- Reddish corrosion: This is likely galvanic corrosion. While it may eventually lead to leaks, it’s not immediately threatening.
- Ant-like nest patterns on the coil: This is likely formicary corrosion, a more serious problem caused by acetic and formic acids.
If you start to notice these issues, don’t panic. The best approach is to focus on prevention (filtration, ventilation, and humidity control) and monitor the performance of your system closely.
When to Call in the Experts
If your HVAC system isn’t performing as it should, corrosion may already be impacting it. Warning signs like inconsistent cooling or heating, strange noises, or rising energy bills mean it’s time to call in professional help.
Protect Your HVAC System for the Long Run
Preventing corrosion in your HVAC system is all about staying proactive. By improving your indoor air quality, controlling humidity, using safer cleaning practices, and keeping an eye out for corrosion signs, you can extend the life of your HVAC system and save yourself from costly repairs down the line.