How Air Conditioners Work | The Cool Science

How Air Conditioners Work

The fascinating physics that keeps you cool on hot summer days

The Basic Principle

Air conditioners don't actually "create" cold air. They work by transferring heat from inside your home to the outside, using some clever physics and a special chemical called refrigerant.

This process relies on two fundamental scientific principles:

  • When a liquid evaporates, it absorbs heat from its surroundings
  • When a gas condenses, it releases heat to its surroundings

Heat Transfer Machine

Moving heat from inside to outside

Key Components

Compressor

The "heart" that pumps refrigerant through the system

Condenser Coil

Releases heat to the outside air

Expansion Valve

Controls refrigerant flow into evaporator

Evaporator Coil

Absorbs heat from indoor air

The Cooling Cycle

1. Compression

Refrigerant gas is compressed, increasing its temperature and pressure.

2. Condensation

Hot gas flows through condenser coils, releasing heat to outside air and condensing into liquid.

3. Expansion

Liquid refrigerant passes through expansion valve, dropping pressure and temperature.

4. Evaporation

Cold refrigerant absorbs heat from indoor air, evaporating back into gas.

Types of Air Conditioners

Window Units

All components in one box that fits in a window. Affordable but only cools one room.

Best for single rooms

Split Systems

Separate indoor and outdoor units. Quieter and more efficient than window units.

Best for whole-home cooling

Central AC

Uses ductwork to distribute cooled air throughout entire home. Most powerful option.

Best for large homes

Cooling Efficiency Tips

Maximize Your AC's Performance

  • Keep filters clean - check monthly during peak usage
  • Seal leaks in ductwork to prevent cooled air loss
  • Use ceiling fans to help distribute cool air

Energy Saving Strategies

  • Set thermostat to 78°F (26°C) when home, higher when away
  • Close blinds/curtains during hottest parts of day
  • Consider a programmable or smart thermostat