Equipment types
HVAC covers a wide range of hardware, and a symptom means different things depending on which of it you own. These pages define each category and link to the references that apply to it.
Ductless mini-splits
Wall-mounted, floor, and cassette indoor units paired with an outdoor condenser, with no duct network between them.
Open categoryHeat pumps
Air-source and hybrid systems that move heat in both directions, covering cooling in summer and heating in winter.
Open categoryMulti-zone systems
One outdoor unit serving several indoor heads, where a fault in one zone can present across the whole system.
Open categoryDucted and central air
Central split systems with an air handler or furnace coil distributing conditioned air through ductwork.
Open categoryControls and thermostats
Wall controllers, handheld remotes, smart thermostats, and the wiring that carries their signals.
Open categoryAir handlers and coils
Indoor blower assemblies, evaporator coils, drain pans, and the condensate path that leaves the building.
Open categoryFurnaces
Gas and electric heating appliances that supply warm air to a duct system.
Open categoryBoilers and hydronics
Wet heating systems that circulate hot water through radiators, cylinders, or underfloor loops.
Open categoryIndoor air quality
Filtration, ventilation, humidifiers, and dehumidifiers that condition air rather than temperature alone.
Open categoryLight commercial
Rooftop units, VRF and VRV systems, and cassette installations serving offices, retail, and small industrial spaces.
Open category