St. Louis, MO Noise from Specific Sources: HVAC & Mechanical Noise (2026)

City Code § 15.51.040(J) excludes 'all single- and multifamily residential air-conditioning units, HVAC systems, cooling towers and/or heating systems' from the stationary-noise-source limits set in § 15.51.030's Table I, so a neighbor's residential AC compressor can't be cited for exceeding the dB(A) table. The exemption doesn't erase liability entirely: the same subsection preserves the right of the City, or any other person, to pursue a nuisance claim over the same equipment under other law. HVAC equipment serving commercial, office or industrial buildings is not exempt: it must stay within the Table I limits for its zoning district, as low as 55 dB(A) daytime and 50 dB(A) nighttime in the 'A' through 'E' residential districts.