Haessly Air Duct Service in La Mesa's Casa de Oro district is a veteran-owned air duct cleaning operation based on Palm Avenue in the 91941 ZIP below Mt Helix. The service removes accumulated dust, pet dander, and microbial growth from supply and return registers, plenums, and main trunk lines—contaminants that also degrade the furnace and condenser systems serviced by Hamel's Air Conditioning & Heating Inc. Negative-pressure extraction using HEPA-filtered vacuum equipment pulls debris from the ductwork without releasing particulate into the living space, an especially critical process in pre-1980 La Mesa homes with original galvanized steel ductwork. Dryer vent cleaning is a complementary service addressing the lint-blockage fire risk identified in U.S. Fire Administration data, and duct-access work in older homes occasionally reveals condensate-line issues best handled by drain specialists such as E-Drains, Inc. Full-system remediation of both flex-duct and rigid-metal ductwork involves antimicrobial fogging of the complete HVAC distribution network after negative-pressure extraction of all supply, return, and trunk-line segments.