John Air Duct Cleaning & HVAC serves Carlsbad's La Costa corridor from Gateway Road in 92009, providing residential and commercial air-duct cleaning alongside HVAC maintenance and repair. Duct-cleaning protocols remove accumulated dust, mold spores, and allergens from supply and return plenums, a scope that parallels the carpet and upholstery extraction work Zerorez performs for North County homeowners addressing whole-house indoor-air quality. The HVAC service side covers AC and furnace diagnostics, refrigerant recharging, and blower-motor replacement across all major residential brands. Post-cleaning inspections sometimes reveal rodent or insect nesting inside ductwork, a discovery that triggers coordination with structural pest operators such as Mission Pest Control to clear infestations before duct sealing can proceed. Complete duct-system cleaning includes register removal, negative-pressure vacuuming of trunk lines, and HEPA-filtered particulate capture rated to trap 99.97 percent of particles at 0.3 microns.