Longmont does not have a dedicated HVAC noise ordinance. Air conditioners, heat pumps, and pool equipment are regulated as fixed noise sources under the general decibel limits in LMC § 10.20.110: 50 dB(A) residential at night and 55 dB(A) residential during the day, measured 25 feet from the unit.
Title 10, Chapter 10.20 contains no HVAC- or mechanical-equipment-specific section. Instead, condensers, heat pumps, mini-split outdoor units, and pool-equipment pumps fall under the general 'fixed source' decibel ceilings in LMC § 10.20.110 Tables A and B: Residential 50 dB(A) night / 55 dB(A) day; Commercial 55 dB(A) night / 65 dB(A) day; Industrial 75 dB(A) day and night — measured at least 25 feet from the source using an A-weighted sound level meter. § 10.20.110(E) applies the most restrictive zone limit when the equipment can be measured from more than one zone (e.g., a rooftop unit on a commercial building near residences must meet the residential limit at the residential property line). § 10.20.100(B) also makes 'nonvehicular engines' audible 25 feet away between 10:00 p.m. and 7:00 a.m. prima facie unreasonable, which can apply to gas-powered backup generators. Installations also need a mechanical permit through Longmont Building Services, but the building code itself does not set a separate decibel cap.
General penalty: up to $999.00 fine and/or up to 180 days jail per LMC violation.
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