COMCOR 31B.00.03. Control of Noise from Heat Pumps and Air Conditioners on Property in Residential Zones
COMCOR 31B.00.03 Control of Noise from Heat Pumps and Air Conditioners on Property in Residential ZonesLink
Montgomery County, Md., COMCOR § 31B.00.03.01 (2026)
31B.00.03.01 PurposeLinkCopy Citation
This regulation is established to control the noise from outdoor heat pumps and air conditioners which are installed on property in residential zones with lot areas less than 12,000 square feet, except as excluded by 31B.00.03.02 and 31B.00.03.05. It is created under authority conferred upon the County Executive by Subsection 31B-3(d) of the Noise Control Ordinance, Chapter 31B, Montgomery County Code 1984, as amended, and Subsection 17-2(a) of Chapter 17, “Electricity,” Montgomery County Code 1984, as amended.
Montgomery County, Md., COMCOR § 31B.00.03.02 (2026)
31B.00.03.02 Limitations on ScopeLinkCopy Citation
(a)
This regulation does not apply to outdoor heat pumps and air conditioners installed to serve:
(1)
Buildings on property in residential zones, or in mixed-zones, which are used in whole or in substantial part for purposes other than as dwelling units;
(2)
Apartment buildings more than 30 feet in height; or
(3)
Condominium or cooperative residential buildings where both the sound source and sound receiver are located on the same premises.
(b)
All heat pumps and air conditioners not covered by this regulation must comply with the maximum permissible sound levels at the property line which are in Section 31B-5, “Maximum Permissible Sound Levels Generally,” of the Noise Control Ordinance.
Montgomery County, Md., COMCOR § 31B.00.03.03 (2026)
31B.00.03.03 DefinitionsLinkCopy Citation
(a)
Tonal noise:
(1)
Is any sound that is composed of one or more pure tones. A pure tone means any sound that can be distinctly heard as a single pitch, and
(2)
In this regulation, a pure tone exists if the sound pressure level within the one-third octave band with the tone exceeds the arithmetic average of the sound pressure levels of the two contiguous one-third octave bands by —
(A)
5 dB for center frequencies of 500 hertz and above, or
(B)
8 dB for center frequencies between 160 and 500 hertz, or
(C)
15 dB for center frequencies less than or equal to 125 hertz.
(b)
dB: is the abbreviation for decibel.
(c)
dBA: is the abbreviation for decibels measured on the A scale of a sound level meter.
(d)
Director: is the Director of the Department of Environmental Protection or his designee.
Montgomery County, Md., COMCOR § 31B.00.03.04 (2026)
31B.00.03.04 StandardsLinkCopy Citation
(a)
The maximum permissible sound level at the property line for the outdoor unit of any heat pump or air conditioner located on residential lots less than 12,000 square feet in area must not exceed 60 dBA.
(b)
If the sound is determined to be a tonal noise as defined in 31B.00.03.03, the maximum permissible sound level at the nearest property line must not exceed 55 dBA.
(c)
As an exemption from 31B.00.04(a), the maximum permissible sound level at the property line for the outdoor unit of any heat pump or air conditioner manufactured before July 1, 1989, located on residential lots less than 12,000 square feet in area must not exceed 65 dBA. If the sound from an outdoor unit manufactured before July 1, 1989, is determined to be a tonal noise, the maximum permissible sound level at the property line must not exceed 60 dBA. This subsection 4(c) expires on July 1, 1999.
Montgomery County, Md., COMCOR § 31B.00.03.05 (2026)
31B.00.03.05 ExemptionLinkCopy Citation
If it is not practical to comply with 31B.00.03.04 of this regulation, the owner may apply for a Special Exemption in accordance with Section 31B-13 of the County Code:
(a)
The exemption application must be submitted at least twenty-eight days prior to starting the installation of the outdoor heat pump or air conditioner.
(b)
The Director must notify the owners and the occupants of the adjacent properties of this application by mail or hand delivery.
(c)
Notified owners and occupants will be given one week after receipt of this notice to reply in writing.
(d)
In approving any Special Exemption, the Director may either specify a period for its duration or make it permanent.
(e)
If the exemption is for a limited period, the owner of the building must notify the purchaser in writing of the expiration date of the exemption prior to executing any applicable sales agreement.
(f)
The Director may waive the fee required to be submitted with an application for a Special Exception, if the Director finds that the owner has made a good faith effort to mitigate noise from equipment installed before July 1, 1989, with the best technology available.
Montgomery County, Md., COMCOR § 31B.00.03.06 (2026)
31B.00.03.06 ResponsibilitiesLinkCopy Citation
(a)
Owner. After July 1, 1989, the owner of an existing or replacement outdoor unit is responsible for complying with the maximum permissible sound level requirements of 31B.00.03.04.
(b)
Director.
(1)
The Director may assign a designee to enforce this regulation.
(2)
The Director has the authority to :
(A)
issue notices and orders to remove equipment or install a sound barrier for any unit which is violating the property line sound levels cited in 31B.00.03.04.
(B)
require replacement, modification, redesign of the installation, or repairs to any outdoor heat pump or air conditioner system which is in violation of this regulation or associated exemption currently in effect.
(C)
grant exemptions as provided in See 31B.00.03.05.
(3)
The Director may issue notices of violation as well as civil or criminal citations.
Montgomery County, Md., COMCOR § 31B.00.03.07. (2026)
31B.00.03.07. PenaltiesLinkCopy Citation
(a)
It is unlawful for an owner, as specified in Subsection 6(a), not to comply with the maximum permissible sound levels described in 31B.00.03.04 of this regulation.
(b)
Such a failure is a violation of Subsection 31B-5(b)(2) of the County Code, 1984.
Montgomery County, Md., COMCOR § 31B.00.03.08 (2026)
31B.00.03.08 SeverabilityLinkCopy Citation
The provisions of this regulation are severable. If a court holds that a provision is invalid or inapplicable, the remainder of the regulation remains in effect.
Montgomery County, Md., COMCOR § 31B.00.03.09Sunset (2026)
31B.00.03.09Sunset Date for 31B.00.03.04(c)LinkCopy Citation
31B.00.03.04 expires on July 1, 1999.
Montgomery County, Md., COMCOR § 31B.00.03.10 (2026)
31B.00.03.10 Effective DateLinkCopy Citation
This regulation becomes effective on July 1, 1989.