A central air conditioner moves heat from inside your home to the outdoors using refrigerant, an indoor coil, an outdoor compressor and a blower. A heat pump uses the same parts plus a reversing valve, so it can run the cycle backward in winter and bring heat inside instead.
What are the main parts of a central AC or heat pump?
Most homes have a split system: an outdoor unit with the compressor and condenser coil, an indoor air handler or furnace with the evaporator coil and blower, and copper lines connecting them.
The outdoor unit holds the compressor (the pump that moves refrigerant), the condenser coil (the large finned coil that wraps the cabinet) and a fan that pulls air across that coil. The indoor side holds the evaporator coil, which sits on top of a furnace or inside an air handler, and the blower that pushes air through your ductwork.
Two copper pipes, called the line set, carry refrigerant between the two halves. The thermostat on your wall is the brain that tells everything when to start and stop. Your ductwork, supply registers and return grilles finish the loop by delivering conditioned air to each room and pulling it back.
How does a central air conditioner actually cool your home?
It does not make cold. Refrigerant absorbs heat from your indoor air at the evaporator coil, then the compressor pumps that heat outside, where the condenser coil releases it.
Warm air from your rooms is pulled through the return and across the cold evaporator coil. The refrigerant inside the coil boils at a low temperature and soaks up heat. The compressor squeezes that warm refrigerant vapor into a hot, high-pressure gas and sends it outside. As the outdoor fan blows air over the condenser coil, the refrigerant gives up its heat and turns back into a liquid, ready for another trip.
Cooling is only half the job in Central Arkansas. As humid air crosses the cold coil, moisture condenses on it like water on a cold glass. That water drips into a pan and drains away through a condensate line. When a system is sized and running correctly, you feel both cooler and drier air.
How is a heat pump different from a central AC?
A heat pump is an air conditioner that can run in reverse. A reversing valve flips the refrigerant flow so the outdoor coil gathers heat from outside air and the indoor coil releases it.
Even cool winter air holds heat, and a heat pump moves that heat indoors rather than burning fuel to create it. In summer it cools exactly like a central AC. Because the outdoor coil gets cold in heating mode, frost can build on it, so the system runs short defrost cycles, and you may see steam rising from the outdoor unit. That is normal.
Most heat pumps have auxiliary heat, usually electric heat strips in the air handler, for very cold mornings or during defrost. Central Arkansas winters are usually mild enough that a heat pump carries most of the load, but a system leaning on auxiliary heat all the time is worth having checked because heat strips cost more to run.
What goes wrong, and what does it feel like at home?
Most problems show up as warm air, ice, water or noise. Each symptom points to a different part, which is why a technician tests the system instead of guessing.
- Ice on the indoor coil or the larger copper line: often a dirty filter, a weak blower or low refrigerant from a leak.
- Water around the indoor unit, or a system that shuts off on hot afternoons: a clogged condensate drain tripping a safety switch.
- Outdoor unit hums but the fan does not spin: commonly a failed capacitor or motor.
- Heat pump blowing cool air in winter: a reversing valve, defrost or thermostat setting issue.
- Short on-off cycles: an oversized system, a thermostat problem or restricted airflow.
- Rooms that stay sticky even when the temperature looks right: airflow, sizing or refrigerant charge problems that keep the coil from pulling out moisture.
What can you safely check before you call?
Start with the simple things: thermostat mode and batteries, the air filter, the breakers for both indoor and outdoor units, and clear space around the outdoor unit.
Make sure the thermostat is set to Cool or Heat, not Fan or Off, and that the set point is a few degrees past the room temperature. A clogged filter can shut a system down by freezing the coil, so check it. If a breaker tripped, reset it once. If it trips again, leave it off and call, because repeated tripping points to an electrical fault. Keep grass, leaves and stored items a couple of feet away from the outdoor unit so it can breathe.
Skip anything involving refrigerant, electrical panels inside the equipment or the gas valve. Those are jobs for a licensed technician.
How does CASC work on central AC and heat pump systems?
CASC repairs, maintains and replaces central air and heat pump systems across Central Arkansas. We install Rheem HVAC equipment as a Rheem Pro Partner and service major brands.
Our technicians are licensed and certified, and the company is fully insured and bonded. A repair visit starts with a $99 service call on weekdays or $149 on weekends and holidays. We offer same-day service when availability allows, seven days a week from 7:00 AM to 6:00 PM.
If you would rather stay ahead of breakdowns, our Residential HVAC Maintenance Plan includes two visits a year: a spring cooling tune-up and a fall heating tune-up. When a system reaches the end of its life, a replacement estimate is free.
What should you read next?
If you are weighing a new system, compare heat pumps with gas furnaces next. If something is not working now, see what happens when you book a repair visit.
Frequently asked questions
Is a heat pump the same thing as an air conditioner?
In cooling mode, yes. A heat pump has the same basic parts as a central AC, plus a reversing valve that lets it move heat into your home in winter. A standard central AC only cools and is usually paired with a furnace for heat.
Why is there water dripping near my indoor unit?
Your AC pulls moisture out of the air, and that water drains through a condensate line. If the line clogs, water backs up into the pan and can overflow or trip a safety switch that shuts the system off. A technician can clear the line and check the pan and switch.
Why does my heat pump outdoor unit steam in winter?
That is usually a normal defrost cycle. The system briefly reverses to melt frost off the outdoor coil, and the melting frost can look like steam. If the unit is covered in thick ice that never clears, have it checked.
Does CASC work on brands other than Rheem?
Yes. CASC installs Rheem HVAC equipment and services major brands, so you can call us for repairs or maintenance on the system you already have.
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Related guides
- Heat pump vs gas furnace in Central Arkansas A heat pump uses electricity to move heat and also cools your home. A gas furnace burns natural gas to make heat and pairs with a separate air conditioner. Both can work well in Central Arkansas. The right choice depends on gas service at your home, your ductwork, your utility rates and how you like your home to feel.
- SEER2, HSPF2 and AFUE explained SEER2 rates how efficiently an air conditioner or heat pump cools over a season. HSPF2 rates how efficiently a heat pump heats. AFUE rates how much of a gas furnace's fuel becomes heat in your home. Higher numbers use less energy, but only when the system is sized and installed correctly.
- How ductwork affects comfort and bills Yes, your ducts can be the reason some rooms stay hot, the house gets dusty or bills climb. Leaky ducts lose cooled air into attics and crawlspaces, undersized or crushed runs starve rooms of air, and missing returns choke the system. Sealing, airflow corrections or duct changes often fix it.
- Rheem heating and cooling systems Rheem builds central air conditioners, heat pumps, gas furnaces and air handlers in a range of efficiency and comfort levels. CASC is a Rheem Pro Partner and installs Rheem systems across Central Arkansas, with a 10-year parts and 2-year labor install warranty and manufacturer registration on every new system.
Is your AC or heat pump acting up?
Call 501-307-1310 or send a request. Same-day service when availability allows, 7:00 AM to 6:00 PM, seven days a week.
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