⭐ Air Conditioning FAQs & Tips — Expert HVAC Answers for South Metro Atlanta Homeowners
When your air conditioner stops cooling, blows warm air, freezes up, or struggles during Georgia’s extreme summer heat, you need clear answers you can trust. At John’s Heating, Cooling, and Appliance Repair, we bring 28+ years of hands-on HVAC expertise to help homeowners in Fayetteville, Peachtree City, Newnan, Senoia, Tyrone, Sharpsburg, Griffin, and Zebulon understand the most common AC problems — and how to fix them quickly.
This AC FAQ page was created from real questions we hear every day on service calls across South Metro Atlanta. Whether your system is low on refrigerant, your evaporator coil is frozen, your vents aren’t blowing cold air, or your AC simply won’t keep up when temperatures rise above 95 degrees, the answers below will help you diagnose what’s happening and when to call a professional.
Our goal is to give you simple explanations, expert tips, and reliable guidance so you can protect your HVAC system, avoid costly repairs, and keep your home comfortable year-round. If you ever need fast, local help — including 24-hour emergency AC repair — our team is always just a phone call away.
Why did my AC stop cooling?
Several issues can cause your AC to stop cooling, including a clogged air filter, a frozen evaporator coil, low refrigerant, or a malfunctioning compressor. It’s best to call a professional HVAC company. John’s Heating, Cooling, and Appliance Repair can inspect the system and provide fast and accurate repairs.
Why is my AC not cooling when the outdoor temperature is above 95 degrees?
In extreme Georgia heat, AC units may struggle to keep up. Higher outdoor temperatures put more strain on the system, making it harder to dissipate heat. Regular maintenance, proper insulation, and ceiling fans can help boost performance during heat waves.
Should I have to add Freon to my AC unit every year?
No. If you need refrigerant added to your AC system every year, you have a leak somewhere in the system. Refrigerant doesn’t get "used up." Contact a licensed HVAC technician to locate and repair the leak and to recharge your system properly.
What are the most common HVAC problems?
Clogged filters, low refrigerant levels, faulty thermostats, and dirty coils are among the most common HVAC problems we encounter. Regular maintenance and tune-ups can help prevent many of these issues.
What does SEER stand for?
SEER stands for Seasonal Energy Efficiency Ratio. It measures how efficiently an air conditioner uses electricity to cool your home. A higher SEER rating means better efficiency and lower energy bills.
Why is the SEER rating different from what my salesperson quoted?
The SEER rating depends on both the outdoor and indoor components of the HVAC system. The final rating is based on the combination installed. Upgrading the indoor unit can increase total system efficiency.
How does an AC unit cool and dehumidify?
Warm air is drawn in through return ducts.
The air passes over cold evaporator coils that remove heat and moisture.
Water condenses and drains outside while the cool air is recirculated indoors.
What brand is the best?
Top-performing AC brands include Trane, Amana, Ruud, Carrier, Rheem, Lennox, and Goodman. The best choice depends on your home size, energy needs, and budget. We help you choose the right one.
What is the life expectancy of my AC unit?
Most AC units last 10-12 years with proper maintenance. Poor maintenance or frequent repairs may shorten that lifespan. Routine inspections can help extend the life of your AC unit.
Should I repair or replace my AC system?
If your system is over 10 years old and requires frequent or expensive repairs, replacing it may save you money over time. Newer units offer higher SEER ratings and energy savings.
What size filter should I get, and what type is best?
Use the size printed on your old filter or check your system manual. For better filtration, use pleated filters or media air cleaners. They remove more dust and allergens than standard filters.
Do my AC and heat pump need maintenance?
Yes. Maintenance prevents breakdowns and improves efficiency. Schedule service twice a year—once in spring for AC and once in fall for heating systems.
Should I have preventive maintenance, and how often?
Yes, we recommend biannual maintenance. Preventive care helps catch minor problems early and keeps your HVAC system running longer with fewer surprises.
What are the advantages of a programmable thermostat?
Programmable thermostats improve energy efficiency by automatically adjusting temperatures. You save money without sacrificing comfort by setting home schedules, away, and sleep hours.
What temperature should I set my thermostat to?
72°F is a good starting point for comfort. Adjust it slightly up or down depending on your preference. Keeping it steady helps save energy. Smart thermostats make temperature control easier.
I hear the blower running, but no air is coming from the vents. Why?
Check for a frozen evaporator coil or a dirty air filter. If airflow is blocked, the blower won’t be able to push cool air. Turn off the system and call for service if needed.
How cold should the air coming from my vents be?
The air from your supply vents should be at least 17 degrees colder than room temperature. If it isn’t, your system may be low on refrigerant or in need of service.
Is it essential to clean the condenser coil?
Yes. The outdoor condenser coil should be cleaned annually to ensure efficient heat release. A dirty coil can reduce cooling performance and cause higher energy bills.
What is the job of the AC contactor?
The contactor acts like a switch, controlling power to your air conditioner’s compressor and condenser fan motor. When your thermostat calls for cooling, the contactor engages and sends voltage to the outdoor unit. If the contactor fails, your AC won't turn on. Replacing a faulty contactor is a standard AC repair we perform across Fayetteville and the surrounding areas.
What is the AC capacitor for?
The capacitor stores and delivers a quick burst of electricity to start the compressor and fan motors. Without a working capacitor, your air conditioner may hum but not start. Bad capacitors are among the most common causes of AC failure, especially during Georgia's summer heat. If your system won’t kick on, it may be time to replace the capacitor.
What does the compressor do in an air conditioner?
The compressor is the heart of your AC system. It pressurizes the refrigerant and circulates it between the indoor evaporator coil and outdoor condenser coil. This process removes heat from your home. A damaged compressor can cause warm air to blow from your vents, strange noises, or total system failure. Compressor replacement is a major repair and sometimes signals it's time for a full system upgrade.
What is a heat exchanger, and what is it for?
The heat exchanger is a metal chamber inside your furnace that transfers heat from combustion gases to the air blowing through your ductwork. While it’s mostly associated with heating systems, it's vital for HVAC safety. A cracked heat exchanger can leak carbon monoxide and should be replaced immediately. We inspect heat exchangers during routine HVAC maintenance visits in Fayetteville, Peachtree City, and Newnan.
What is the job of the AC condenser coil?
The condenser coil is located in your outdoor unit. Its job is to release the heat that the refrigerant has absorbed from inside your home. A fan blows air over the coil to cool the refrigerant back into a liquid. When the condenser coil is dirty or damaged, your AC will run inefficiently or even shut down. Annual coil cleaning is part of our spring AC tune-up service.
How does the evaporator coil work?
The evaporator coil is inside your air handler or furnace. Warm air from your home is drawn in and blown over the cold evaporator coil. The coil absorbs heat and moisture, cooling and dehumidifying the air. The cooled air is then circulated back through your home. If the coil is frozen or dirty, your system may stop cooling properly and need professional attention.
What is a TXV (Thermostatic Expansion Valve) and how does it work?
The TXV controls how much refrigerant flows into the evaporator coil. It senses the refrigerant's temperature and pressure and adjusts the flow to optimize efficiency. A malfunctioning TXV can lead to poor cooling, high energy bills, or frozen coils. Diagnosing and replacing a faulty TXV requires a trained HVAC technician, like our licensed team at John’s Heating, Cooling, and Appliance Repair.
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How cold should the air be coming out of my supply vents if the house is 75 degrees?
If your home is 75°F, the air coming out of your supply vents should typically be between 55°F and 58°F—around 17 to 20 degrees cooler than the room temperature. This temperature drop, known as the “Delta T,” helps determine if your AC is cooling properly. If your system isn't reaching this range, it could indicate low refrigerant, a dirty coil, or poor airflow—common problems we repair across Fayetteville and Peachtree City.
What should the humidity level be in my house in July?
In Georgia’s hot and muggy July climate, your indoor humidity should stay between 40% and 55% for comfort and air quality. If it's higher, you may feel sticky or notice mold and mildew. Your AC helps dehumidify, but if it struggles, we can install whole-home dehumidifiers or inspect your evaporator coil and airflow for performance issues.
What is a condensate pump in an air conditioning system?
A condensate pump removes the excess moisture that collects when your air conditioner dehumidifies the air. It pumps the water from the drain pan to a nearby drain or outside the home. If the condensate pump fails, it can cause water leaks or shut down your AC system. We inspect and replace faulty pumps to prevent water damage and ensure safe operation.
What is an ambient thermostat?
An ambient thermostat (or ambient temperature sensor) measures the temperature of the air surrounding the HVAC equipment. It helps the system adjust performance based on real-time conditions, especially in systems with variable-speed or inverter-driven compressors. Faulty ambient sensors can lead to inaccurate readings, uneven cooling, or cycling problems—something our techs frequently diagnose during AC repairs in Newnan, Griffin, and Senoia.
What should my suction pressure be when using R-410A refrigerant?
For systems using R-410A, the typical suction (low-side) pressure should range from 110 to 145 psi, depending on indoor temperature and humidity. At an indoor temperature of 75°F, suction pressure should generally be around 125 psi under normal operating conditions. However, exact values vary by system type. Low or high suction pressure can signal a refrigerant issue, a restriction, or a failing compressor. Our EPA-certified HVAC team uses accurate gauges and superheat/subcooling readings to diagnose AC issues accurately.
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