Why is my air conditioner blowing warm air
Why Is My Air Conditioner Blowing Warm Air? Expert Advice from Spark Heating and Cooling, Sunnyvale, CA
There’s nothing worse than turning on your air conditioner during a hot day in Sunnyvale, CA, only to discover it’s blowing warm air instead of the refreshing cool breeze you expected. If your AC isn’t cooling properly, it’s not just uncomfortable—it can be a sign of a larger issue within your HVAC system.
At Spark Heating and Cooling, we often get calls from frustrated homeowners wondering why their air conditioners are running but not cooling. The good news? Many causes are easy to identify—and in some cases, simple to fix.
In this article, we’ll break down the most common reasons your AC is blowing warm air, how to troubleshoot the issue, and when it’s time to call in the professionals.
1. Incorrect Thermostat Settings Before assuming the worst, check the thermostat. It might sound obvious, but it’s one of the most common causes we see at Spark Heating and Cooling in Sunnyvale, CA.
What to check:
2. Dirty Air Filter: A clogged air filter restricts airflow to your AC system. When airflow is limited, your evaporator coil can freeze, and your system can no longer cool the air effectively—resulting in warm air blowing from your vents.
Solution:
3. Low Refrigerant Levels Your AC uses refrigerant (usually R-410A or R-22) to absorb heat and cool your home. If your system is low on refrigerant, it can’t absorb enough heat, and you’ll notice warm air coming from your vents.
What are the signs of low refrigerant:
If you suspect low refrigerant, contact Spark Heating and Cooling in Sunnyvale, CA to schedule a refrigerant leak test and recharge.
4. What causes Frozen Evaporator Coil: Your AC’s evaporator coil sits inside the air handler and is responsible for absorbing heat from your home’s air. If the coil gets too cold, it can freeze—literally forming a block of ice. When this happens, your AC can’t do its job.
Causes of frozen coils:
5. Outdoor Unit Isn’t Running Properly: Your AC has two main parts: the indoor unit (air handler) and the outdoor condenser unit. If the outdoor unit isn’t working correctly, your system can’t release heat—resulting in warm air indoors.
Things to check:
6. Tripped Circuit Breaker Sometimes the outdoor unit stops working because its breaker tripped. This means the indoor unit (blower) keeps running, but the condenser isn’t—which can make it feel like warm air is blowing.
How to fix it:
7. Leaky Ductwork Cool air travels through a network of ducts before it reaches your rooms. If there are holes, cracks, or disconnected ducts—especially in unconditioned spaces like attics or crawlspaces—cool air could be escaping, and warm air could be drawn in.
Leaky ducts are common in older homes in Sunnyvale, CA and should be professionally sealed or replaced.
8. Aging or Failing System If your AC is over 10–15 years old, warm air could simply be a sign that the system is at the end of its lifespan. Components like compressors, coils, and fans wear out over time, making the system less effective and more prone to problems.
If your system frequently needs repairs or can’t maintain temperature, it may be more cost-effective to replace it with a new, energy-efficient unit.
When to Call Spark Heating and Cooling – Sunnyvale, CA If you’ve tried the basic fixes—like changing your filter or resetting the thermostat—and your AC is still blowing warm air, it’s time to bring in the pros.
Spark Heating and Cooling offers:
✅ Fast, same-day diagnostics
✅ Licensed HVAC technicians
✅ Honest, affordable pricing
✅ Repairs, refrigerant services, and complete system replacements
✅ 5-star customer service across Sunnyvale, CA
Our experts will thoroughly inspect your system, identify the root cause, and get your home cool again—fast.
How to Prevent Future AC Problems Routine maintenance is the key to preventing AC breakdowns. Here’s what we recommend:
Don’t Sweat It- What to do when your air conditioner is blowing warm air, it’s more than an inconvenience—it’s a signal that something’s wrong. Whether it’s a simple filter change or a more serious mechanical issue, it’s always better to act fast and protect your system from further damage.
If you're in Sunnyvale, CA, trust Spark Heating and Cooling to get to the bottom of the problem. Our friendly, knowledgeable team is here to restore your comfort and peace of mind.
Need help with your AC?
📞 Call Spark Heating and Cooling Sunnyvale, CA (404)-458-8057
📍 Your trusted HVAC experts for repair, replacement, and maintenance
There’s nothing worse than turning on your air conditioner during a hot day in Sunnyvale, CA, only to discover it’s blowing warm air instead of the refreshing cool breeze you expected. If your AC isn’t cooling properly, it’s not just uncomfortable—it can be a sign of a larger issue within your HVAC system.
At Spark Heating and Cooling, we often get calls from frustrated homeowners wondering why their air conditioners are running but not cooling. The good news? Many causes are easy to identify—and in some cases, simple to fix.
In this article, we’ll break down the most common reasons your AC is blowing warm air, how to troubleshoot the issue, and when it’s time to call in the professionals.
1. Incorrect Thermostat Settings Before assuming the worst, check the thermostat. It might sound obvious, but it’s one of the most common causes we see at Spark Heating and Cooling in Sunnyvale, CA.
What to check:
- Is the thermostat set to “COOL” and not “HEAT” or “FAN”?
- Is the temperature setting lower than the current room temperature?
- Are the batteries in the thermostat working?
2. Dirty Air Filter: A clogged air filter restricts airflow to your AC system. When airflow is limited, your evaporator coil can freeze, and your system can no longer cool the air effectively—resulting in warm air blowing from your vents.
Solution:
- Check your air filter. If it’s dirty, replace it.
- Spark Heating and Cooling Sunnyvale, CA recommends changing your air filter every 1–3 months, especially during high-use seasons.
3. Low Refrigerant Levels Your AC uses refrigerant (usually R-410A or R-22) to absorb heat and cool your home. If your system is low on refrigerant, it can’t absorb enough heat, and you’ll notice warm air coming from your vents.
What are the signs of low refrigerant:
- Warm air from vents
- Hissing or bubbling sounds near the unit
- Ice on the refrigerant line or evaporator coil
If you suspect low refrigerant, contact Spark Heating and Cooling in Sunnyvale, CA to schedule a refrigerant leak test and recharge.
4. What causes Frozen Evaporator Coil: Your AC’s evaporator coil sits inside the air handler and is responsible for absorbing heat from your home’s air. If the coil gets too cold, it can freeze—literally forming a block of ice. When this happens, your AC can’t do its job.
Causes of frozen coils:
- Dirty air filters
- Low refrigerant
- Poor airflow
- Blocked return vents
- Turn the AC off and let the ice melt (this may take a few hours).
- Check and replace your air filter.
- Make sure vents are clear and open.
5. Outdoor Unit Isn’t Running Properly: Your AC has two main parts: the indoor unit (air handler) and the outdoor condenser unit. If the outdoor unit isn’t working correctly, your system can’t release heat—resulting in warm air indoors.
Things to check:
- Is the outdoor unit receiving power?
- Are there leaves, debris, or dirt blocking the unit?
- Do you hear strange noises or notice the fan isn’t spinning?
6. Tripped Circuit Breaker Sometimes the outdoor unit stops working because its breaker tripped. This means the indoor unit (blower) keeps running, but the condenser isn’t—which can make it feel like warm air is blowing.
How to fix it:
- Go to your home’s electrical panel.
- Look for the AC condenser breaker.
- If it’s in the middle or OFF position, reset it.
- If it trips again, do not keep resetting it—call a professional.
7. Leaky Ductwork Cool air travels through a network of ducts before it reaches your rooms. If there are holes, cracks, or disconnected ducts—especially in unconditioned spaces like attics or crawlspaces—cool air could be escaping, and warm air could be drawn in.
Leaky ducts are common in older homes in Sunnyvale, CA and should be professionally sealed or replaced.
8. Aging or Failing System If your AC is over 10–15 years old, warm air could simply be a sign that the system is at the end of its lifespan. Components like compressors, coils, and fans wear out over time, making the system less effective and more prone to problems.
If your system frequently needs repairs or can’t maintain temperature, it may be more cost-effective to replace it with a new, energy-efficient unit.
When to Call Spark Heating and Cooling – Sunnyvale, CA If you’ve tried the basic fixes—like changing your filter or resetting the thermostat—and your AC is still blowing warm air, it’s time to bring in the pros.
Spark Heating and Cooling offers:
✅ Fast, same-day diagnostics
✅ Licensed HVAC technicians
✅ Honest, affordable pricing
✅ Repairs, refrigerant services, and complete system replacements
✅ 5-star customer service across Sunnyvale, CA
Our experts will thoroughly inspect your system, identify the root cause, and get your home cool again—fast.
How to Prevent Future AC Problems Routine maintenance is the key to preventing AC breakdowns. Here’s what we recommend:
- Change filters regularly (every 1–3 months)
- Schedule annual AC tune-ups
- Keep the outdoor unit clean
- Don’t block vents
- Fix small issues before they become big problems
Don’t Sweat It- What to do when your air conditioner is blowing warm air, it’s more than an inconvenience—it’s a signal that something’s wrong. Whether it’s a simple filter change or a more serious mechanical issue, it’s always better to act fast and protect your system from further damage.
If you're in Sunnyvale, CA, trust Spark Heating and Cooling to get to the bottom of the problem. Our friendly, knowledgeable team is here to restore your comfort and peace of mind.
Need help with your AC?
📞 Call Spark Heating and Cooling Sunnyvale, CA (404)-458-8057
📍 Your trusted HVAC experts for repair, replacement, and maintenance