Why HVAC heat exchangers corrode in humid and coastal environments

LOUMIS Air is outlining the main causes of corrosion in HVAC heat exchangers, from moisture and condensation to water chemistry, dissimilar metals and contaminants. The company says the issue is especially relevant in Louisiana and Mississippi, where humidity and coastal exposure can accelerate deterioration.

Why it matters: - Corrosion can reduce heat exchanger efficiency, shorten equipment life and create hidden damage that is not obvious during a casual inspection. - Louisiana and Mississippi face added risk because humidity, coastal air and airborne salts can speed deterioration of exposed metal components. - Early detection matters because corrosion may begin in small areas before broader failure appears.

What happened: - LOUMIS Air published guidance on the common causes of corrosion in HVAC heat exchangers. - Jennifer Lingo of LOUMIS Air said heat exchangers operate in environments where temperature changes, moisture and contaminants can all be present. - Lingo said identifying contributing conditions is important when evaluating equipment condition and performance.

The details: - Heat exchangers transfer thermal energy between air, water, refrigerant or combustion gases while keeping those fluids or gases separate. - Corrosion is metal deterioration caused by chemical or electrochemical reactions with surrounding substances. - Moisture is a major factor because condensation can form when warm, moisture-containing air or combustion gases meet cooler metal surfaces. - In combustion equipment, water vapor created during normal combustion can condense if gases cool enough. - That condensate can contain compounds that accelerate corrosion on susceptible metals, depending on fuel type and combustion conditions. - Modern condensing equipment is designed to manage condensation through suitable materials and drainage systems. - Equipment not designed for sustained condensation may corrode faster when moisture repeatedly forms in areas with limited drainage or corrosion resistance. - Commercial and industrial sites can add more risk through cleaning chemicals, manufacturing processes, pool chemicals and airborne particles. - Corrosion can move faster when moisture combines with contaminants that create an aggressive chemical environment. - Heat exchangers may use stainless steel, copper, aluminum, carbon steel or other alloys, and each material responds differently to heat, strength demands and corrosion exposure. - Galvanic corrosion can occur when dissimilar metals are electrically connected in the presence of an electrolyte such as water. - Water quality matters in hydronic systems, cooling towers, boilers and other water-based equipment. - Mineral content, dissolved oxygen, pH and chemical treatment can affect corrosion rates. - Water outside proper operating parameters can contribute to scaling, corrosion or both. - Scale can reduce heat-transfer efficiency and create localized conditions where corrosion develops beneath deposits. - Corrosion can show up as pitting, surface oxidation or deterioration around specific areas instead of uniform rust. - Pitting corrosion can create small cavities or holes that hide serious damage in a limited area. - Crevice corrosion can develop in joints, seams and spots beneath deposits where moisture or contaminants get trapped. - Heating and cooling cycles can expand and contract metals while changing how moisture and contaminants behave on surfaces. - Improper combustion can alter the composition and temperature of combustion gases and contribute to deposits or corrosive conditions. - Condensate drains, pans and related components are designed to move water away from equipment. - Blocked or poorly draining components can leave nearby metal exposed to moisture for longer periods. - Visible warning signs include discoloration, rust, pitting, deposits and water staining. - Unusual operating behavior can also justify further inspection.

Between the lines: - The guidance points to corrosion as a systems problem, not just a metal problem, because moisture, chemistry, temperature and maintenance conditions interact. - Visual appearance alone is not enough to judge severity, since serious damage may hide beneath deposits or appear only in small areas. - In humid, coastal markets, routine HVAC inspection becomes more important because environmental exposure can stack on top of normal wear.

What's next: - LOUMIS Air says routine inspection and review of operating history can help identify corrosion before damage spreads. - Facility operators should watch for drainage issues, unusual combustion behavior and water-quality problems that can drive future deterioration. - The company continues to provide heating, ventilation and air-conditioning services across Louisiana and Mississippi, including commercial and industrial HVAC maintenance and repair.