There’s nothing worse than walking into your home on a hot day, expecting a blast of cool air—only to realize your air conditioner isn’t working.
When your AC stops blowing cold air or won’t turn on at all, it can feel like a total emergency. Fortunately, many common issues are simple to fix and don’t require a professional visit.
In this blog, we’ll walk you through a few easy troubleshooting steps you can try before calling HVAC maintenance. These tips can help you get your AC back up and running—or at least give you a better idea of what’s going wrong.
1. Check the Thermostat
Before delving into complex diagnostics, start with the thermostat. This device serves as the command center for your HVAC system, and even minor issues here can disrupt your comfort.
Verify that the thermostat is set to "cool" mode. It's easy to overlook this setting, especially during seasonal transitions.
Next, confirm that the desired temperature is lower than the current room temperature.
A blank or unresponsive screen might also mean the thermostat isn’t getting power. If your thermostat uses batteries, try replacing them. If it doesn’t, check your home’s circuit breaker to make sure it’s receiving power.
2. Inspect the Circuit Breaker
If your AC isn’t turning on at all, the issue could be electrical. One of the simplest and most commonly overlooked steps to fix your AC in this case is checking your circuit breaker.
Start by locating your home’s breaker panel, usually found in a garage, basement, or utility area. Look for the switch labeled “AC,” “air conditioner,” or “HVAC.”
If the breaker for your AC system has tripped, it will be either in the middle position or fully switched off. Flip the breaker fully to the “off” position, then back to “on.” This can restore power to your AC system if the trip was caused by a one-time surge.
After resetting, give the system a few minutes to see if it powers back on.
If It Trips Again this could be a sign of a deeper electrical issue. If the breaker won’t stay on, don’t continue to reset it. Instead, have a professional evaluate the system to prevent further damage or safety risks.
3. Check the Air Filter
A dirty or clogged air filter is another common cause of poor AC performance. Luckily, replacing it is also an easy fix. If your system runs but doesn’t cool well or airflow feels weak, check your filter.
The filter traps dust, pollen, and debris to keep your air clean. When it gets clogged, this can put extra strain on your system and sometimes cause the evaporator coil to freeze.
Filters are usually behind a return air grille or inside the indoor unit. Slide it out and inspect it. If it looks gray or dusty, it’s time to replace it.
Generally, filters need to be replaced every 3 months, but that can change depending on usage, pets, and allergies. During heavy-use times like summer, checking it monthly is a good practice.
4. Examine the Outdoor Unit
If your thermostat is set correctly and the filter is clean, check the outdoor unit next. This part releases heat from your home, so any blockages can reduce efficiency.
If you find leaves, grass, weeds, and dirt around the condenser, remove them to create at least two feet of clearance.
Check for bent fins, loose wires, or oil spots that might indicate leaks or damage. These issues need professional attention, but catching them early helps avoid bigger problems.
5. Look for Ice Build-Up
Seeing ice on your AC system, especially during the middle of summer, is a clear sign something isn’t working properly. Ice can form on the refrigerant lines or evaporator coil, and it often leads to reduced or no cooling.
If you see ice, turn off your air conditioner completely and switch the fan setting to “on.” This will help the system thaw out.
It may take a few hours for all the ice to melt. Don’t try to scrape the ice off—it can damage the coil.
Once everything is melted and dry, try turning the system back on. If it freezes again or won’t cool properly, there could be a deeper issue like low refrigerant or a malfunctioning part. That’s a sign it’s time for a technician to take a closer look.
6. Check for Water Leaks or Clogged Drain Lines
Air conditioners don’t just cool your home, they also remove moisture from the air. That moisture usually drains away through a condensate line. If that line gets clogged or backed up, water can start to pool where it shouldn’t.
Signs of a Clogged Drain Line
- Water around the indoor unit or near the drain pan
- A full or overflowing drip pan
- A musty smell coming from the vents or unit
If you notice standing water or a backed-up drain, turn off the system to prevent further overflow. Sometimes, you can clear a shallow clog by carefully using a wet/dry vacuum.
If the water keeps coming back, or you're unsure where the clog is, it's best to have the line professionally cleared. Ignoring a drainage issue can lead to water damage, mold growth, or a complete system shutdown.
7. Listen for Strange Sounds or Smells
Sometimes your AC will give you clues it’s not working right through noises or odors. Paying attention to these signs can help you catch problems early.
Unusual noises to watch for include buzzing, humming, rattling, banging, or grinding. If you smell something burning or a musty, moldy odor, these are also indicators of bigger issues.
If you hear or smell anything unusual, it’s best to turn off your AC to avoid further damage or safety risks. Make note of what you’re experiencing, as this will help a technician diagnose the issue faster.
Final Note
When your air conditioner isn’t working, it’s easy to feel overwhelmed—especially on a hot day. By starting with these straightforward checks, you can identify or even resolve common issues quickly.
Remember, regular maintenance and simple care go a long way in preventing problems before they start.
If you’ve tried these steps and your AC still isn’t cooling, or if you notice any signs of electrical or mechanical trouble, it’s best to reach out to a qualified HVAC professional. Prompt attention helps protect your system and keeps your home comfortable all year round.
Commercial Service Is Ready To Help
At Commercial Service, we have dedicated over 75 years to helping Indiana's residents and businesses stay comfortable and satisfied with their heating, cooling, and plumbing. No matter the season, we’ll make sure your HVAC system operates efficiently and effectively.
Commercial Service is the partner you can trust with all of your heating, cooling, and plumbing needs. If you are looking for guidance on your heating system or need to schedule maintenance, please contact us!
