Coil cleaning is the process of removing accumulated dirt, scale, algae, and biological deposits from heat exchanger surfaces to restore thermal efficiency. Regular cleaning maintains system capacity, reduces energy consumption, and prevents equipment failure. Professional cleaning can restore coil performance to 90 to 95 percent of original specifications.
Methods and Frequency
Mechanical cleaning uses brushes or compressed air for light deposits, while chemical cleaning addresses scale and biological growth using biodegradable descalents or inhibited acids. Steam cleaning provides effective sanitization without chemicals. Most facilities require spring and fall cleaning, with quarterly cleaning in high-fouling environments such as coastal or industrial areas. ASHRAE recommends cleaning when pressure drop increases by 15 to 20 percent or capacity drops by 5 percent.
Performance Recovery
Neglected coils exhibit increased pressure drop across the coil, reducing airflow by 10 to 20 percent and increasing fan energy consumption by 15 to 30 percent. Clean coils operate at design conditions, reducing energy costs and extending compressor life by minimizing unnecessary runtime. Proper chemical treatment prevents microbial regrowth and corrosion between cleanings.