What Are The Main Parts Of An AC Unit?

Air Conditioner 101

When the Texas heat cranks up in Seguin and McQueeney, having a properly functioning air conditioner is more than a luxury — it’s a necessity. At Lonestar Air Services, we often hear from local homeowners wondering what exactly makes their AC system tick.

Understanding the parts of a central air conditioning system not only helps you spot issues early but also empowers you to make smarter decisions about maintenance and repairs.

Let’s break down the components of an air conditioner, explain their roles and answer common questions — like how does an air handler work and what part of the AC unit is in the attic?

1. Outdoor Unit (Condenser)

The large metal box outside your home is called the condenser unit. It plays a key role in heat exchange by releasing the heat collected from inside your home into the outdoor air. It houses three essential components:

• Compressor — Often considered the heart of the system, the compressor pumps refrigerant through the system and maintains the pressure levels required for heat exchange.
• Condenser coil — This coil dissipates heat carried by the refrigerant.
• Fan — Helps expel the hot air outside and cool the condenser coil.

Without a functioning condenser, your home would never cool down effectively during those 100-degree Texas summers.

2. Indoor Unit (Air Handler or Furnace)

This is the part of the AC unit that’s usually located in the attic, garage or a dedicated utility closet. In central Texas, attics are a common installation location to save indoor space. So if you’ve ever wondered, what part of the AC unit is in the attic? — this is it!

The air handler consists of:

• Evaporator coil — As warm air from your home is blown across this coil, the refrigerant inside absorbs the heat, cooling the air.
• Blower motor & fan — These push the newly cooled air through your ductwork and into each room.
• Filter slot — This is where you replace your air filter to keep dust and allergens from circulating.

Wondering how an air handler works? It’s essentially the indoor “engine” of your cooling system — drawing in warm air, running it across the cold evaporator coil and sending it back into your home as refreshing, cool air.

3. Ductwork & Vents

While not mechanical parts, your ducts and vents are crucial for air delivery. Cooled air travels from the air handler through the ducts and enters your rooms via ceiling, floor or wall vents. Poorly sealed or insulated ductwork can lead to energy waste — something we often help homeowners in Seguin and McQueeney diagnose and fix.

4. Thermostat

The thermostat is your AC system’s control panel. Whether it’s programmable or a smart thermostat, it tells your system when to turn on and off, based on your desired temperature. Newer smart thermostats can even learn your habits and adjust automatically for comfort and energy savings.

5. Refrigerant Lines

These insulated copper lines connect the indoor and outdoor units. The refrigerant inside is the medium that transfers heat from indoors to outdoors. Without it, the cooling cycle can’t happen.

Why This Matters For Seguin & McQueeney Homeowners

Whether you’re sweating through a hot summer in Seguin or trying to get ahead of repairs in McQueeney, knowing the components of an air conditioner gives you an edge. If something goes wrong — like warm air blowing out your vents or strange noises in your attic — you’ll have a better sense of what’s happening and how to explain it to your technician.

Trust Lonestar Air Services With Your AC Needs

At Lonestar Air Services, we’re proud to serve the hardworking homeowners of Seguin and McQueeney. Whether you need help understanding how your air handler works, replacing a faulty component of your central air conditioning system or just need a seasonal tune-up, our local HVAC pros are ready to help.

Need a service check or have questions? Contact us today to keep your system running cool, clean and efficient — all year long.