# HVAC Systems¶

HEScore allows the definition of up to two HVAC systems which can each include a heating system, cooling system, and duct system. To determine which HPXML elements are associated, the DistributionSystem subelement of HeatingSystem, CoolingSystem, HeatPump is used to find the link to HVACDistributionSystem. Systems that share the same HVACDistributionSystem are determined to be the same HVAC system for HEScore.

Sometimes an HVAC system will not share ducts, for instance a central air conditioner and boiler. In that case, if each of those systems serve a fraction of the home’s load within 5% of each other they will be combined into the same HVAC system for HEScore. If a HeatingSystem and CoolingSystem that are associated with the same HVACDistributionSystem serve differing portions of the house’s heating and cooling load, that weight is averaged to find the combined system weight.

If either a heating or cooling system meets all of the load and two systems of the opposite (cooling or heating, respectively) are required to meet the same fraction of the load, the larger system is split into two for input into HEScore.

To determine the fraction of the home’s heating and cooling load each system serves, each HPXML heating and cooling system is required to have FloorAreaServed or, alternatively FracLoadServed. The two combined HVAC systems that serve the greatest portion of the house’s load are sent to HEScore.

For details about how each kind of HeatingSystem, CoolingSystem, HeatPump, and HVACDistributionSystem are translated into HEScore inputs, see the appropriate subsection: