Coils – HVAC Glossary
Coils are heat exchange components in HVAC systems that transfer thermal energy between refrigerant and air. The evaporator coil absorbs heat to cool indoor air, while the condenser coil releases heat outdoors.
Coils are metal heat exchange components found in air conditioning systems, heat pumps, and refrigeration equipment. These serpentine-shaped tubes allow refrigerant to absorb or release thermal energy as air passes over their surface. Every cooling system contains at least two types of coils working together to move heat from one location to another.
Types of HVAC Coils
The evaporator coil sits inside your home, typically mounted above the furnace or inside the air handler. As warm indoor air flows across this coil, the cold refrigerant inside absorbs heat and humidity, producing the cool, dry air that circulates through your ductwork. This process causes moisture to condense on the coil surface, which then drains away through the condensate line.
The condenser coil is located in the outdoor unit. After refrigerant collects heat from inside your home, it travels to this coil where fans blow outdoor air across the hot metal surface. This allows the refrigerant to release absorbed heat into the outside environment, completing the cooling cycle.
Why Coil Maintenance Matters
Over time, both coils accumulate dirt, dust, pollen, and other airborne particles. This buildup acts as insulation, preventing efficient heat transfer and forcing your system to run longer to achieve desired temperatures. Dirty coils increase energy consumption, reduce cooling capacity, and can lead to system breakdowns.
Professional HVAC technicians clean coils during routine maintenance visits using specialized solutions and tools. For evaporator coils, this prevents mold growth and maintains proper airflow. For condenser coils, removing debris like leaves, grass clippings, and cottonwood seeds keeps the outdoor unit operating at peak efficiency.
Signs Your Coils Need Attention
- Reduced cooling performance despite a functioning system
- Higher than normal energy bills
- Ice formation on the indoor coil
- Visible dirt or debris on the outdoor unit
- Musty odors when the AC runs
- Water leaks near the indoor unit
Regular filter changes help protect coils from excessive dirt accumulation. However, annual professional cleaning remains necessary to maintain system efficiency and prevent premature equipment failure. Clean coils improve air quality, lower operating costs, and extend the lifespan of your HVAC investment.
