HVAC
An umbrella term for the heating, ventilation and air conditioning systems of a building, treated as one interacting system rather than separate pieces of equipment.
What the term covers
HVAC covers the heating, ventilation and air conditioning of a building. The term takes in everything that governs temperature, air renewal and — depending on the installation — humidity: boilers and burners, hot water or steam distribution, air handling units, fans and ductwork, chillers, heat pumps, and the controls that coordinate them.
In French-language documents the equivalent acronyms are CVAC and CVCA, with CVC also in use. They describe the same field, with drafting conventions varying by region.
Three parts, one system
The value of the umbrella term is not linguistic: it is a reminder that the three parts interact. Outdoor air brought in by ventilation has to be heated in winter, which lands directly on the boiler plant’s load. An oversized hot water boiler short-cycles and heats unevenly, which occupants will readily blame on ventilation. Conversely, a fouled HRV drives heating consumption up without any heating equipment being at fault.
HVAC in Québec commercial buildings
The local climate imposes a swing few regions see: one installation has to handle ‑25 °C mornings and humid afternoons above 30 °C. Equipment is therefore worked hard in both directions, and shoulder seasons — when heating and cooling can end up fighting over the same zone — are when coordination failures cost the most.
Coordination and controls
That is exactly what building management systems are for: making equipment bought separately, often years apart and from different manufacturers, work together. An open control network such as BACnet serves that purpose — giving one common view of subsystems that otherwise coordinate only by accident of whatever settings were left in place.