Although HVAC is executed in individual buildings or other enclosed spaces (like NORAD's underground headquarters), the equipment involved is in some cases an extension of a larger district heating (DH) or district cooling (DC) network, or a combined DHC network. In such cases, the operating and maintenance aspects are simplified and metering becomes necessary to bill for the energy that is consumed, and in some cases energy that is returned to the larger system. For example, at a given time one building may be utilizing chilled water for air conditioning and the warm water it returns may be used in another building for heating, or for the overall heating-portion of the DHC network (likely with energy added to boost the temperature).
7) Schedule an annual tune-up with an HVAC professional. A trained HVAC technician can detect most problems before they become major ones. With a cost of around $100 for a routine maintenance call, the benefits will likely outweigh the costs by a considerable margin. A typical tune-up will include various tests to ensure your unit’s internal parts are functioning correctly, as well as a filter check, and a refrigerant charge if needed. Your technician will likely also clear the drain, and clean your unit thoroughly inside and out.