“The heat index in Indianapolis hit 110° last July—and your AC doesn’t get vacation days.”
When your AC is blowing warm air—or worse, nothing at all—it’s more than just an inconvenience. It’s uncomfortable, frustrating, and potentially expensive. As HVAC professionals serving Indianapolis, Indiana, we know how critical your cooling system is, especially during muggy Midwest summers.
Let’s break down the most common reasons your AC unit isn’t cooling, and what you can do about it before calling in the pros.
1. Dirty or Clogged Air Filters
A $10 Fix That Can Save You $1,000
We’re starting here for a reason. A clogged air filter is one of the most common AC problems we see in Indiana homes—and one of the easiest to fix.
When your air filter gets too dirty, it restricts airflow. This can make your system work harder, cause your evaporator coil to freeze, and prevent your AC from cooling your home effectively.
What to Do:
- Check your air filter every 30–60 days during cooling season.
- Replace it if it looks dirty or clogged.
- Use the correct size and MERV rating for your system (not sure? Give us a call!).
2. Low Refrigerant or a Leak
Refrigerant is what allows your AC to absorb and release heat. If levels are low or there’s a leak, the system might run constantly—but the house stays warm.
You might notice:
- Ice buildup on the outdoor unit or refrigerant lines
- A hissing sound (yep, that could be a leak)
- Rising humidity indoors
This isn’t a DIY fix. Refrigerant is a regulated substance and leaks require professional repair.
3. Frozen Evaporator Coils
Yes, This Can Happen Even in the Heat
It sounds counterintuitive—how can something freeze when it’s 90° outside? But this is one of the most frequent causes of an air conditioner not working properly.
Why it Happens:
- Low airflow due to dirty filters or blocked vents
- Low refrigerant levels
- Running the AC non-stop on high humidity days
What to Do:
- Turn off the system and let the coil thaw completely.
- Don’t turn it back on until a technician has checked the unit.
4. Thermostat Troubles
Sometimes it’s not your AC unit—it’s your thermostat. Whether it’s miscalibrated, has a dying battery, or isn’t communicating with your system, it can throw everything off.
Try this first:
- Replace the batteries
- Double-check your temperature settings
- Make sure it’s set to “cool,” not “fan” or “heat”
Still not working right? You might need a new thermostat, especially if yours is over 10 years old.
5. Blocked or Dirty Outdoor Unit
Your outdoor condenser coil is responsible for releasing heat your indoor unit absorbs. But when it’s coated in dirt, leaves, or mulch, it can’t do its job.
Check the outdoor unit:
- Is the area around the unit clear by at least 2 feet?
- Is the coil covered in debris, grass clippings, or grime?
- Are weeds growing up around it?
What to Do:
- Turn off the power and rinse the unit with a garden hose.
- Never use a pressure washer!
- For deeper buildup, schedule a professional cleaning.
6. Electrical or Breaker Issues
This one is often overlooked. If your AC won’t turn on at all—or only part of the system is working—a tripped breaker could be the culprit.
Try this:
- Check your electrical panel for a tripped breaker
- Flip it off and back on
- If it trips again, call an HVAC technician. You may have a short or overloaded circuit.
7. Leaky or Damaged Ductwork
If your AC is running but certain rooms still feel warm, you could have leaky or poorly insulated ducts. Cool air might be escaping into your attic, crawlspace, or walls.
Signs of duct issues:
- Uneven temperatures between rooms
- Weak airflow from vents
- Higher-than-normal energy bills
Duct problems aren’t easy to diagnose on your own. We offer professional duct inspections and sealing services to help your system run efficiently.
When to Call Hoosier Indoor Air
There’s a difference between troubleshooting and guessing. If you’ve tried the basics and your AC unit is still not cooling, it’s time to bring in the experts.
Call us if:
- You hear strange noises or smell something off
- There’s ice on your coils or refrigerant lines
- Your AC is 10+ years old and struggling
- You’ve already checked the filter and thermostat
Fast, Friendly Service for AC Problems in Indianapolis, Indiana
At Hoosier Indoor Air, we’ve helped thousands of Indiana families get their AC running again—quickly, affordably, and with no surprises. Our experienced team is here to help you stay cool and comfortable through the hottest days of summer.
If you’re stuck asking yourself, “Why is my AC unit not cooling?”, don’t wait. Schedule your service or call our team today—we’ll be there when you need us!
