How Do Home Air Conditioners Work?
Published 4/14/2025
Home air conditioners cool your home by removing heat from the indoor air and releasing it outside. An AC system accomplishes this by using a closed-loop refrigeration cycle. This is where a special fluid called refrigerant circulates through coils and changes from liquid to gas, then back to liquid. As it changes state, the refrigerant absorbs heat from inside your home and carries it to the outside unit to be expelled.
A home AC system consists of components such as a compressor, an evaporator coil, a condenser coil, and an expansion valve. The evaporator coil is cooled by the refrigerant, while the condenser coil releases the heat to the outside air. The compressor works as the heart of the AC system, pumping and pressurizing the refrigerant. In this article, we'll go over the air conditioning process, types of air conditioners, and detailed information about AC systems and home air conditioning services offered by Mr. Duct.
How Air Conditioning Works To Cool Your Home
Air conditioners cool your home by extracting heat from indoor air. The indoor air is pulled into the AC system through return ducts by a blower fan. This air passes through a filter to remove dust and then pushes over to the evaporator coil, which is filled with cold refrigerant. Once the air flows across the cold evaporator coil, the refrigerant inside absorbs the heat from the air and evaporates it into gas.
Now that the air has lost a lot of its heat, it is able to be cooled and returned back into the home through ducts and vents. This cycle repeats continuously until the indoor temperature reaches the thermostat setting. To keep this process efficient, home air conditioning services such as annual tune-ups are recommended to prevent dirt buildup and airflow issues.
What Is Central Air Conditioning?
Central air conditioning refers to a cooling system that is designed to cool an entire house from one central location. This is a common setup for Chicagoland homes and typically involves one indoor unit and one outdoor unit installed by a residential HVAC company like Mr. Duct. These AC units are connected by ductwork and refrigerant lines, which deliver cool air to each room.
According to Energy.gov, 66% of U.S. homes have central air conditioning systems as part of their HVAC setup. This can be partly due to the ability to control the climate of the entire house. Regular home air conditioning services help central AC systems continue operating efficiently throughout all seasons.
Understanding The AC Cooling Process
To better understand this cooling process, we'll break it down step-by-step. The four main stages in the cooling cycle are evaporation, compression, condensation, and expansion. This AC cooling process occurs continuously in a loop whenever your AC unit is running.
- Evaporation - This is where heat absorption occurs, where cold liquid refrigerant flows into the indoor evaporator coil and absorbs heat from the warm indoor air. As it absorbs, it evaporates into a low-pressure gas inside the coil. This happens in the indoor unit, where the air is cooled.
- Compression - The gaseous refrigerant now carries the absorbed heat out of the evaporator and into the compressor, which is located in the outdoor unit. The compressor's job is to pressurize the refrigerant gas, preparing it for the next step.
- Condensation - The hot pressurized refrigerant vapor flows into the condenser coil, which is also in the outdoor unit. The refrigerant releases the heat from your house to the outside environment. There's a fan that blows outdoor air across the condenser coil, cooling the refrigerant and causing it to give up its heat to the outside air. As the refrigerant loses heat, it condenses back into a liquid (hence the term condensation). You can actually feel this warm air near your outdoor unit when the AC is running.
- Expansion - After condensing into a high-pressure liquid, the refrigerant passes through an expansion valve, which meters the refrigerant flow and allows the liquid to expand, reducing its temperature. Now, the refrigeration is cold and ready to absorb heat from your home's air again, completing the cycle.
Different Types of Air Conditioners for Homes
Home air conditioning systems come in different configurations, such as split-system air conditioners, packaged air conditioning systems, and ductless mini-split systems. All of these have the same cooling cycle process but differ in how the components are arranged and how the air is delivered.
Split-System Air Conditioners
A split-system air conditioner is the most common type of central cooling system found in homes. This means the components are divided between two main units, one outdoor and one indoor. The outdoor AC units contain the compressor and condenser coil, and the indoor unit contains the evaporator coil. Home air conditioning services for split systems may include spring maintenance tasks like refrigerant checks, coil cleaning, and blower motor inspection. All components are typically serviced by a residential HVAC company like Mr. Duct.
Packaged AC Systems
A packaged air conditioning system combines all the cooling components into one single unit. The AC unit is installed outside the home and can be positioned on the roof or next to the house. Packaged AC systems are often used in situations where a traditional split system would be difficult to install. For example, in a home that does not have a basement, a residential HVAC company like Mr. Duct can confirm compatibility during an inspection. These systems still require routine home air conditioning services to ensure outdoor exposure doesn’t compromise the unit’s efficiency.
Ductless AC Systems
Also known as ductless mini-split systems, this type of AC system works without the need for central ductwork. This can be achieved because each indoor unit has a small air handler that directly cools the room in which it's installed. With this type of AC system, it's common to have multiple indoor AC units while only having one outdoor unit. Ductless systems offer high efficiency and zone-specific cooling, making them a possible recommendation by a residential HVAC company. Proper home air conditioning services for ductless systems include filter cleaning, fan checks, and drainage maintenance for each air handler.
Schedule Air Conditioner Cleaning Services in Chicagoland Areas
Now that you understand how an AC units work, it's important to schedule home air conditioning services regularly. Over time, an AC system's performance can decline due to dust, dirt, and wear. Specific examples of these issues include clogged air filters and buildup on coils.
This is why it's recommended to have annual AC cleaning from reputable companies like Mr. Duct Air Duct Cleaning, who specializes in home air conditioning services for the Chicagoland area including Naperville, Barrington, Chicago, Lisle, and surrounding cities. View our current coupons and contact one of our experts today!