We do not provide Duct Cleaning services. We apologize for any inconvenience. Darlington's #1 HVAC Service Been in business over 20 years. Servicing over 40 years We are a growing local independant business. Providing heating service to established and new customers. We provide an efficient and friendly service throughout hvac (heating, ventilation, and air conditioning) is the technology of indoor and automotive environmental comfort. hvac system design is a major subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. Refrigeration is sometimes added to the field's abbreviation as Hvac or Hvcr, or ventilating is dropped as in Hacr (such as the designation of Hacr-rated circuit breakers). hvac is important in the design of medium to large industrial and office buildings such as skyscrapers and in marine environments such as aquariums, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors.