Will vinegar damage AC coils?

No, distilled white vinegar will not damage your air conditioning evaporator or condenser coils when used properly in diluted amounts for routine cleaning and maintenance. Vinegar is a mild organic acid containing about five percent acetic acid, making it safe to use on copper, aluminum, and plastic components commonly found in HVAC systems without causing chemical corrosion or pitting. In fact, diluted vinegar is frequently recommended by technicians as a natural, safe agent to clean dirty coils or keep condensate drain pans and PVC lines free of algae and mold slime. However, it is always important to rinse the coils thoroughly with clean water after applying any cleaning solution to remove loosened debris and prevent lingering acidic residues. You should strictly avoid using harsh industrial acids, strong bleach concentrations, or aggressive chemical drain cleaners on your coils, as those caustic substances will rapidly corrode aluminum fins and copper tubing.