An HVAC split system is the most common type of heating and cooling system found in homes and buildings today. It gets its name from being an HVAC system that includes an indoor unit and an outdoor unit as two separate devices. Unlike older or less common types like packaged units or window units, which contain all components in a single piece of equipment, a split system divides the main functions between these two distinct parts.
Understanding the Two Main Parts
A split system consists primarily of these two components:
- The Outdoor Unit: This unit is typically placed on a concrete slab outside the building. It contains the system's compressor, condenser coil, and fan. During the cooling season, the compressor circulates refrigerant, and the fan helps dissipate heat from the condenser coil to the outside air.
- The Indoor Unit: Located inside the building, usually in a basement, attic, closet, or garage. This unit houses the evaporator coil and the blower fan. During cooling, the blower pulls warm indoor air over the cold evaporator coil, removing heat and humidity before circulating the cooled air back into the building via ductwork. For systems that also provide heating (a heat pump split system), the indoor unit also contains components that work in reverse to provide warm air.
These two units are connected by refrigerant lines (often copper tubing) and electrical wiring, allowing the refrigerant to circulate and exchange heat between the indoor and outdoor environments.
Why Choose a Split System?
Split systems offer several advantages that make them popular:
- Efficiency: Modern split systems, especially those with high SEER (Seasonal Energy Efficiency Ratio) and HSPF (Heating Seasonal Performance Factor) ratings, can be very energy efficient.
- Flexibility: They can be configured for cooling only (air conditioner) or both heating and cooling (heat pump). They also integrate well with furnaces for dual-fuel systems.
- Quiet Operation: The noisiest components (compressor and condenser fan) are located outside, leading to quieter operation inside the building compared to window units or some packaged systems.
- Zone Control Potential: While not inherent to all split systems, they can be adapted with zoning technology to control temperatures independently in different areas of a building.
Split System vs. Packaged Unit
Here's a quick comparison highlighting the key difference:
| Feature | Split System | Packaged Unit |
|---|---|---|
| Components | Separate Indoor & Outdoor Units | All components in one unit |
| Location | Indoor unit inside, Outdoor unit outside | Usually on a roof or beside the building |
| Installation | Requires running refrigerant lines and electrical connections between units | Simpler installation, often just duct connections |
| Common Use | Residential homes, small commercial buildings | Rooftops, areas with limited indoor space |
As the reference states, the defining characteristic is the division of the system into two separate components, unlike a packaged unit or a window unit where the complete HVAC system is contained as one single piece. This fundamental design influences everything from installation requirements to system performance and indoor comfort levels.
Examples of split systems include standard central air conditioning systems and residential heat pumps. They are typically connected to a network of air ducts that distribute conditioned air throughout the building, controlled by a central thermostat.
