When Georgia Nights Get Cold, Your Home Shouldn’t Be.
Why Is My Furnace Blowing Cold Air?
- Why is the issue happening
- Whether you can fix it yourself
- When it’s time to call a professional HVAC technician
Just like homes in Planterra Ridge, White Oak, Summergrove, Avery Park, Sun City Peachtree, and Historic Downtown Newnan, every heating system is a little different — but the root causes of cold air problems are usually the same. Below are eight detailed reasons your furnace may be blowing cold air, along with step-by-step solutions.
1. Thermostat Setting Is Incorrect
Cause:
Fan setting is set to ON instead of AUTO
If your thermostat is set to ON, your blower fan runs continuously — even when the furnace isn’t heating. That means your vents will sometimes blow cool air between heating cycles.
Solution:
- Set thermostat to HEAT
- Set the fan to AUTO
- Raise the temperature a few degrees above room temperature.
Also check:
- If someone changed the setting (familiar in busy homes)
- If your scheduled program is overriding your manual setting
- If the thermostat screen is blank or flickering → go to Reason #2.
2. Thermostat Battery or Power Issue
Cause:
Low batteries or thermostat wiring issues
If the thermostat doesn’t have enough power, your furnace may not receive the correct heating signal.
Solution:
- Replace thermostat batteries (if applicable)
- Ensure thermostat breakers are ON
- Check for loose thermostat wires (tighten gently)
If you recently installed a new thermostat yourself and the furnace stopped heating → the thermostat may not be compatible with your HVAC system.
In that case, → professional evaluation is needed.
3. Dirty or Clogged Air Filter
Cause:
Restricted airflow causes overheating, triggering a safety shutdown
When the furnace overheats, the burners shut off — but the fan continues blowing, causing cold air to move through the vents.
Solution:
- Turn off the system
- Replace the air filter with a pleated, high-quality filter
- Restart furnace
Check filters every 1–3 months, especially in high-dust households or homes near golf courses/pollen corridors like White Oak or Planterra Ridge.
4. The Furnace Hasn’t Warmed Up Yet
Cause:
Normal furnace warm-up delay
Some furnaces have built-in delay timers to prevent blowing cold air before the burners fully ignite.
Solution:
Let the furnace run for 3–5 minutes before evaluating.
If the air stays cold → continue to the following reason.
5. Condensate Line Is Clogged
(High-Efficiency 90% - 96% Furnaces Only)
Cause:
Water from the exhaust vent pipe is building up in the vent pipe or furnace and is causing the safety switch to open and → shut off the gas going to the burners.
Solution:
Please call John's Heating, Cooling, and Appliance Repair to diagnose the problem and make the necessary repair.
(DIY)
- Locate condensate drain line (usually white PVC or clear plastic tubing - if system is in a basement)
- Flush with 50/50 vinegar + warm water
- Ensure the condensate drain line is not frozen or kinked
When to call a professional:
If water is pooling or the furnace is shutting off repeatedly.
6. Pilot Light or Ignition Failure
Cause:
Weak flame, dirty flame sensor, faulty ignition board, inducer motor is not pulling a substantial enough vacuum, pressure switch is defective, or gas supply disruption.
This is a widespread problem in older homes in:
- Historic Downtown Newnan
- Sun City Peachtree (Griffin)
- South Fayetteville ranch homes
Solution:
If your furnace has a pilot flame:
- Check if the flame is lit
- If out, follow the manufacturer’s relight instructions
- If the flame won’t stay lit → flame sensor needs cleaning or replacement
- If your furnace is newer, it may have an electronic hot-surface igniter, which must be professionally tested.
7. Leaking or Damaged Ductwork (Flex Duct)
Cause:
Warm air escapes before reaching the rooms. This is especially common in homes with:
- basements
- crawlspaces
- Homes with flex ductwork
Solution:
- Inspect accessible ducts for holes, loose joints, or disconnected runs
- Seal small gaps with UL-rated foil HVAC tape
- Avoid duct tape — it fails under heat
- For full-system duct leaks → schedule a pressure test and professional sealing.
8. Cracked Heat Exchanger (Serious Safety Alert)
Cause:
Metal fatigue over the years of heating cycles. Not changing the filters regularly.
A cracked heat exchanger can:
- Leak carbon monoxide
- Fail to transfer heat into the airflow
- Cause the furnace to blow cold air
- It can be deadly to people sleeping in the house
Solution:
This requires immediate professional service. Turn off the furnace and call a licensed HVAC provider.
5 Most Common Homeowner Questions About Cold Air from Furnaces
1. Can I keep running my furnace if it’s blowing cold air?
No — continuing to run it can cause compressor damage or heat exchanger failure.
2. How do I know if it’s a repair or replacement problem?
If repairs cost more than 30% of the system replacement cost → replacement makes more financial sense.
3. How long should a furnace last in Peachtree City?
10–15 years, but units in Georgia run longer and harder than in northern states → lifespan shortens.
4. Can a dirty filter really cause cold air?
Yes, and also heat exchanger damage if ignored in the long term.
5. Should I call for emergency service?
If you smell gas, burning odors, or your thermostat is unresponsive → YES.
Local Heating Service You Can Trust
If your furnace is blowing cold air, don’t wait until the temperature drops again.
We proudly serve:
Peachtree City (Planterra Ridge, White Oak areas, Aberdeen, Braelinn)
Fayetteville (Whitewater Greek, The Canoe Club, Lakemont)
Newnan (Summergrove, Avery Park, Historic Downtown)
Senoia (Keg Creek Landing, Grove Park, Historic Downtown Senoia)
Griffin (Sun City Peachtree)
Schedule Heating Service:
https://www.john-hc-appliance.com/heating-repair-peachtree-city
24/7 Emergency Heating Repair:
https://www.john-hc-appliance.com/emergency-hvac-repair
📞 Call Now: (678) 603-7775
Expert AC replacement in Peachtree City, GA. Learn 7 signs it’s time to replace your air conditioner. 24/7 HVAC service—call (678) 603-7775!
Is Your Furnace Making Strange Noise At Night?
BBB-accredited, family-owned, and factory-trained on Subzero & Wolf — John’s Heating, Cooling, and Appliance Repair is South Metro Atlanta’s most trusted HVAC expert.
Discover 8 major benefits of installing a Wi-Fi thermostat. Cut energy bills, improve comfort, and control your AC from anywhere in South Metro Atlanta.
Avoid costly AC failures in Fayetteville & Peachtree City. Learn 5 common problems and how preventive maintenance keeps your system running strong all summer.
Find out if heating or cooling costs more in Georgia homes. Learn how runtime, SEER2, AFUE, ducts, and thermostat habits impact Fayette & Peachtree City bills.
❄️ Does Freon Wear Out? The Complete Guide to AC Refrigerant Myths & Leaks For more than 28 years, John’s Heating, Cooling, and Appliance Repair has been the trusted choice for homeowners and businesses across Fayetteville, Peachtree City , Newnan , Griffin , Sharpsburg , Senoia , Tyrone , Zebulon , and South Metro Atlanta . One of the most common questions we hear is: 👉 “Does Freon wear out in my air conditioner like motor oil in a car?” The short answer: No. Refrigerant doesn’t wear out — it leaks. In this guide, we’ll bust the myths, explain the science, and show you why leaks are the real problem — plus how our team fixes them the right way. 🔍 Part 1: Why People Think Freon “Wears Out” When an air conditioner stops cooling, it’s easy to assume the refrigerant (often called Freon) just “ran out.” The logic makes sense — cars need oil changes and fluid top-offs. But refrigerant doesn’t work that way. How Refrigerant Really Works Closed-Loop System – Refrigerant runs in a sealed cycle, absorbing and releasing heat. It isn’t consumed. No Combustion – Unlike fuel or oil, refrigerant doesn’t burn or break down. Constant Cycle – The same refrigerant circulates through compression and expansion, year after year. 👉 If your AC is low on refrigerant, it’s not because it wore out — it’s because it escaped through a leak. ❄️ Part 2: Why Leaks, Not Wear, Cause Problems Refrigerant leaks are the real issue. Once refrigerant escapes, your AC loses efficiency and struggles to keep up with the summer heat in Georgia. Common Signs of a Refrigerant Leak Warm air blowing from vents Ice buildup on coils or refrigerant lines Hissing or bubbling noises near the unit Higher electric bills despite poor cooling The Cost of Ignoring a Leak Burned-out compressor – one of the most expensive AC repairs Energy bills up 30–50% – wasted money every month Poor indoor air quality – sticky, uncomfortable air System breakdowns – failure right when you need it most 👉 Just “topping off” Freon doesn’t solve the problem. It’s a temporary band-aid that guarantees you’ll be calling again. 🔬 Part 3: The Science of Refrigerant Refrigerant is designed to last the entire lifespan of your AC system. It circulates through indoor and outdoor coils, absorbing and releasing heat. It doesn’t get used up or burned. It simply changes state — liquid to gas and back again. If levels are low, the system is leaking. Period. 👉 Learn more about our Air Conditioning Repair in Peachtree City page. ❄️ Part 4: Why Honest Repairs Beat “Top-Offs” Unfortunately, some HVAC companies keep homeowners stuck in the Freon myth. They’ll top off refrigerant year after year without fixing the actual leak. The Wrong Way: Refrigerant Top-Offs Quick cooling, but only temporary Repeated service calls = higher costs Worsening leaks that damage your compressor The Right Way: Leak Detection & Permanent Repair At John’s Heating, Cooling, and Appliance Repair, we: Use advanced tools to locate leaks. Repair the source of the problem. Recharge your system correctly. ✅ Results: Better cooling, lower bills, longer system life, and peace of mind. 👉 Check out our Air Conditioning Repair Fayetteville page to see how we do it right. 🌟 Why Experience Matters With over 28 years of hands-on HVAC and refrigeration expertise, John has solved every issue imaginable — from frozen coils and failed compressors to cracked heat exchangers and ductless installations. That’s why homeowners and businesses across South Metro Atlanta keep calling us back. We don’t believe in shortcuts. We believe in education, honesty, and lasting solutions. 👉 Explore more on our Air Conditioning Repair Newnan page. 📞 Call the Local Experts for Honest AC Repair Don’t let refrigerant myths drain your wallet or leave you sweating through another Georgia summer. Trust the team that’s been keeping families and businesses comfortable for nearly three decades. 📍 Serving Fayetteville , Peachtree City , Newnan , Sharpsburg , Senoia , Griffin , Tyrone , Zebulon, and South Metro Atlanta 📞 Call (678) 603-7775 today or schedule service online. ❓ FAQ: Freon, Leaks & AC Repair Does Freon wear out? No. If refrigerant levels are low, it means there’s a leak. How long does refrigerant last? The entire life of your system — unless it escapes. Can I add more refrigerant? Not without sealing the leak. Otherwise, it will just leak out again. What happens if I ignore a leak? Expect higher bills, poor cooling, and eventual compressor failure. ✅ Final Takeaway Refrigerant doesn’t wear out. If your AC is low, it’s leaking — and leaks require professional repair. At John’s Heating, Cooling, and Appliance Repair, we offer honest, long-lasting solutions that keep your system running efficiently and your family comfortable. 📞 Call (678) 603-7775 today — and put an end to the Freon myth once and for all.
Why Your Furnace Keeps Turning Off in Fayetteville or Peachtree City (and How to Fix It)
Subzero refrigerator and freezer temperature tips to keep food fresh, prevent spoilage, and improve cooling performance
Commercial Cooler Troubleshooting Tips:
