Lafayette, LA Noise from Specific Sources: HVAC & Mechanical Noise (2026)

Section 34-366(d) singles out 'steady pure tones', sound from a mechanical device that a noise control officer determines has a steady tonal quality, meaning it's dominated by a single frequency or a narrow cluster of frequencies (described in the code as a whine, hum, or buzz) and doesn't fluctuate by more than plus or minus three decibels. Heating, ventilating and air-conditioning units, refrigeration units, and transformers are named examples. Because tonal noise is more noticeable to the human ear than broadband sound at the same level, the code subtracts five dB(A) from whatever limit would otherwise apply under Table I of § 34-366(a), so a residential daytime ceiling of 60.00 dB(A) becomes 55.00 dB(A) for a whining condenser unit, and the residential nighttime ceiling of 50.00 dB(A) becomes 45.00 dB(A).

The code then adds a hard floor specific to housing: residential HVAC sound sources can't exceed 55 dB(A) at night no matter how the tonal-reduction math works out. Measurement is taken by a noise control officer with a sound level meter at or within the property line of the receiving property, per § 34-366(a) and § 34-367. A property owner running a noisy rooftop unit or window air conditioner that keeps a neighbor's residence above these thresholds after 10:00 p.m. is exposed to enforcement, and a repeat offense in the prior 12 months forecloses the minor-violation correction period under § 34-370(a)(2).