How Air Conditioners Work?

Learn how air conditioners work

How Air Conditioners Work?

(Last Updated On: September 27, 2018)

Every spring and summer, many homeowners rely on a critical appliance for their home comfort. Yes, many people rely on air conditioning for home cooling. However, what happens if an AC issue occurs? Do you know how air conditioners work?

Understanding basic home maintenance, which includes your air conditioning system, helps homeowners make informed decisions when issues arise. Therefore, the following provides a high level overview sharing how an air conditioner works and common warning signs of potential problems.

How Air Conditioners Work: AC System Components

how air conditioners work; critical ac components

Air conditioners help keep homes cool during hot and humid temperatures. Yes, air conditioners monitor and regulate home air, which means removing particles and humidity. For example, air conditioners contain drains (or drip water) because the AC removes moisture from the air, which helps reduce the temperature. However, the main role an AC plays remains the same; cool your home. And the major AC components accomplish this goal by moving air between the inside (cold side) and outside (hot side).

how air conditioners work; the ac cycle

The AC system works through a cooling cycle based on evaporation. The AC contains a liquid that evaporates inside of your home, which cools the house. To start, liquid inside the air conditioner evaporates (into a gas) over a set of coils making the coils extremely cold. Next, a fan blows air across the coils, which provides the cold air circulating throughout your home.

The cooling cycle continues by turning the gas back into a liquid. The compressors squeezes the gas, which produces a lot of heat. The fan blows the heat off the liquid (this is the fan blowing in the AC unit in the backyard), which then enters the home again. The cycle repeats as your AC runs and cools your home.

AC Components: Cold Side

The cold side of an air conditioner contains an evaporator and fan. Ultimately, the fan powers the cooling process by blowing the air over chilled coils and into the ductwork, which cools your home.

  • The evaporator receives the liquid (commonly known as the refrigerant).
  • The fan blows over the coils (and ultimately provides the cold air found inside your home).

AC Components: Hot Side

The hot side of an air conditioning system contains the compressor, condenser and fan. The hot side vents hot air from the compressed refrigerant to the outside.

  • The compressor provides pressure turning the gas (from the evaporated liquid) back into a liquid.
  • The condenser facilitates the heat transfer (providing the exchange from gas to liquid).
  • The fan blows the hot air off liquid (which is what we see and hear when the AC runs).

For a visual overview of how an air conditioner works, then How Stuff Works simplifies the process.

How Air Conditioners Work: Warning Signs

learn about AC warning signs

The old adage “an ounce of prevention is worth a pound of cure” remains true when it comes to your air condition system as well. For example, routine annual inspections and tune-ups not only prolong the life of your AC, but also ensure it runs efficiently throughout the summer. However, even with preventative maintenance, problems still occur. Fortunately, AC systems offer a few warning that foreshadow potential issues.

Additionally, homeowners should take a few minutes every month (during the summer) and ask yourself a few questions about your AC unit.

  • Did you check the thermostat?

Sometimes the problem is simple, your thermostat might just need a fresh set of batteries. Look for the battery symbol or light on your thermostat indicating the batteries need to be changed.

  • Did you check the air filter?

Check the air filter because an AC might run continually, but your home temperature may not cool down if you have a dirty filter. Fortunately, replacing a dirty air filter is simple and inexpensive.

  • What is the temperature?

During the AC installation process, technicians complete load measurements optimizes for the standard summer temperatures in your area. Unfortunately, summer brings some unbearably hot days. This means the outdoor temperature could be too intense for older systems to function at maximum efficiency. If this is case, it could be time to upgrade.

  • Is the AC noisy?

A noisy AC indicates a potential problem. A loud or noisy AC If this is the case, there could be an issue with the compressor motor or condenser fan, which can compromise the system’s efficiency.

  • Did you check the drain line?

Is water surrounding the indoor unit that couldn’t have come from another source? If so, your drain line is likely plugged and you need to have a professional AC technician out to inspect the system.

How Air Conditioners Work: Routine Maintenance

how air conditioners work; routine maintenance

Many homeowners rely on professionals for routine heating and cooling inspections. Energy Star explains why routine professionals inspections help save money (and energy).

“Maintain your equipment to prevent future problems and unwanted costs. Keep your cooling and heating system at peak performance by having a contractor do annual pre-season check-ups. Contractors get busy once summer and winter come, so it’s best to check the cooling system in the spring and the heating system in the fall. To remember, you might plan the check-ups around the time changes in the spring and fall.”

However, for some homeowners with sufficient knowledge, an initial inspection helps identify issues. Plus, every homeowner should understand how their home operates and the specific checks any contractor conducts during a visit. Therefore, please find the general heating and cooling inspection items.

  • Checks controls of the system ensuring proper and safe operation during every cycle of run time.
  • Checks thermostat settings ensuring home comfort during various seasons
  • Tightens electrical connections measuring voltage and current on motors looking for any faulty connections that potentially causes safety issues.
  • Lubricates all moving parts reducing friction in motors and increasing efficiency.
  • Inspects condensate drain for multiple appliances, such as central air conditioner, furnace and/or heat pump (when in cooling mode) because plugged drain potentially causes water damage.

Finally, Energy Star recommends all homeowners complete a monthly check themselves as well.

“Inspect, clean, or change air filters once a month in your central air conditioner, furnace, and/or heat pump. Your contractor can show you how to do this. A dirty filter can increase energy costs and damage your equipment, leading to early failure.”

How Air Conditioners Work: Types of ACs

learn about various types of central air conditioners

Although the general operations of any air conditioner remains the same, every family and home may have different cooling needs. Plus, not everyone lives in the Northeast with hot, humid conditions during the summer. Cooling needs vary by location, such as the desert, which needs home cooling year round. Therefore, please find some common central air conditioning systems that ideally help identify the right AC for your needs.

Split Systems

Typically, when someone thinks about a central air system, they think about a split system. This is the most common type of central air in the US. Plus, traditional split systems are the most cost effective for homes with a central furnace because they share the same ductwork throughout the home.

Heat Pumps

Heat pumps work well in mild climates. There are two main types of heat pumps: air-source and air-to-water. The most common air-source heat pumps (air-to-air) move heat into your home during the colder months and push heat out during the summer. Secondly, air-to-water (ground-source) heat pumps are not as common, but work in a similar fashion. These pumps use a hydronic distribution system to heat and cool. Additionally ground-source heat pumps use the earth or groundwater to heat and cool. These pumps are also known as geothermal, earth-energy, or geoexchange pumps.

Mini-Split

For homes without existing ductwork, then mini-split systems work well. In a mini-split system, there is still an outdoor compressor and condenser, along with an indoor unit. Typically, the indoor unit is mounted high on a wall and connects to the outdoor unit via tubing. However, mini-splits only cool the room or space where they are mounted. Fortunately, for smaller homes or ranch-style houses, mini-splits may provide sufficient cooling needs. Conversely, for larger homes, multiple mini-splits make them expensive compared to a standard split system.


SolvIt provides homeowners throughout Connecticut with exceptional technicians offering AC repair, installation and service 24/7. If anything goes wrong with your current system, the experienced team of SolvIt HVAC technicians diagnose, explain, and fix any problem with a minimum delay, a maximum of professional skill and customer courtesy.

SolvIt Home Services offers all of our air conditioning repair and maintenance services to all of Connecticut. Find all of our CT services areas here or schedule your service today.

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