Abstract: An antimicrobial lighting system is used to reduce microbial growth on surfaces in or on air conditioning and/or heating equipment. In some examples, antimicrobial light within one or more antimicrobial wavelength ranges is applied to inactivate one or more microorganisms on target surface(s) within or on a packaged terminal air conditioner (PTAC). The antimicrobial light may include light within a first antimicrobial wavelength range and/or light within a second antimicrobial wavelength range. The antimicrobial lighting system may include an array of individually controllable antimicrobial light segments. An array controller may individually control activation of the one or more antimicrobial light segments based on the status information or commands received from a PTAC controller or from an external computing device.