How Central Air Conditioning Works

By Lyle Weischwill | Sep. 16, 2015 2:05 pm PST

How Central Air Conditioning Works

Most of us don’t really know how central air conditioning works. All we know is that in the heat of the summer we can rely on our central cooling systems to keep our homes comfortable no matter the outside temperature.

Unlike window units, which are only used to cool one room or area at a time, central air conditioning systems cool an entire house or building from one location. Central AC is the most convenient and effective way to get relief from hot, humid weather. Understanding how your air conditioning works will help with routine upkeep and offer insights about what to look for if you’re shopping for a new HVAC system.

Your AC works much like your refrigerator, with the walls of your home keeping the cold air in and the hot air out. This is why it’s important to keep the doors and windows closed while the AC is running. A typical central AC system is known as a “split system.” In this configuration, the “cold side,” an indoor coil, is separate from the “hot side,” an outdoor air conditioner, or compressor unit.

The cold side consists of an expansion valve and cold coil. It’s typically positioned in the furnace or air handler inside your home. The outdoor compressor unit consists of a long, hot coil with a fan, along with temperature control logic, giving the system the ability to compare the indoor temperature to the thermostat setting and adjust accordingly.

The cycle begins when the thermostat signals that the air temperature inside the home needs to be lowered.

  • Through the ductwork in your home, the compressor pulls heat and moisture from indoors and removes it from your home.
  • At the same time, warm air from outside is pulled in and blown over the indoor unit’s cold coil, thereby cooling the air, and preparing it to be blown into the house.
  • The heat that was transferred to the coil from the warm air is pumped back outside, and the cooled air is pushed back into the home through the ductwork and dispensed into the rooms via vents.

Heating and cooling costs account for around 40% of the average household’s energy bills. Purchasing an energy-efficient cooling system with a SEER above 14.5 can significantly reduce your monthly utility bill. Knowing the ins and outs of your central AC system can reduce future maintenance costs over the lifetime of your system and help increase the energy efficiency of your home, leaving you with more money in your pocket! If you have any questions about the best AC system for your home, the certified professionals at Sears Home Services will point you in the right direction.

Quick Answers: How Does Central Air Conditioning Work?

  • Your AC works much like your refrigerator

  • The compressor pulls heat and moisture from the air

  • The warm air is blown over cooling coils then sent back into the air

  • Heat from the coils is pumped back outside

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