❄️ Cooling & Heat Pumps

Central Air Conditioning Basics

The indoor coil, outdoor unit, refrigerant circuit, blower and ductwork explained.

Safety boundary: Refrigerant and high-voltage work require trained service. Never open service valves or electrical panels.

The cooling cycle

Refrigerant absorbs heat at the indoor evaporator coil and rejects it outdoors at the condenser. The furnace or air-handler blower moves household air across the indoor coil.

Humidity matters

A system must run long enough to remove moisture. Oversized equipment may cool quickly but control humidity poorly. Airflow that is too high or low can also reduce performance.

The drainage path

Water condensed from indoor air drains through a pan and pipe. Blockage can cause leakage or trigger a safety switch.

Useful owner checks

Confirm thermostat settings, clean filter, open registers, outdoor airflow and visible drain condition. Shut the system off if the indoor coil is iced or water is damaging the home.

Useful questions to record
  • Is airflow weak, warm, intermittent or normal?
  • Is the outdoor unit operating?
  • Is there ice or water around the indoor equipment?

Related guides